log interpretation charts
TRANSCRIPT
8/21/2019 Log Interpretation Charts
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LogInterpretationCharts
2009 Edition REm
RInd
RLl
NMR
Neu
Dens
SP
GR
Gen
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8/21/2019 Log Interpretation Charts
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8/21/2019 Log Interpretation Charts
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Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Genera
l
Symbols Used in Log Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-1 . . . . . . . . . . . . . . . . . . . . . . 1
Estimation of Formation Temperature with Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-2 . . . . . . . . . . . . . . . . . . . . . . 3
Estimation of Rmf and Rmc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-3 . . . . . . . . . . . . . . . . . . . . . . 4
Equivalent NaCl Salinity of Salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-
4 . . . . . . . . . . . . . . . . . . . . . . 5
Concentration of NaCl Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-5 . . . . . . . . . . . . . . . . . . . . . . 6
Resistivity of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-6 . . . . . . . . . . . . . . . . . . . . . . 8
Density of Water and Hydrogen Index of Water and Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-7 . . . . . . . . . . . . . . . . . . . . . . 9
Density and Hydrogen Index of Natural Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-8 . . . . . . . . . . . . . . . . . . . . . 10
Sound Velocity of Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-9 . . . . . . . . . . . . . . . . . . . . . 11
Gas Effect on Compressional Slowness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-9a . . . . . . . . . . . . . . . . . . . 12
Gas Effect on Acoustic Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen
-9b . . . . . . . . . . . . . . . . . . . 13
Nuclear Magnetic Resonance Relaxation Times of Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-10 . . . . . . . . . . . . . . . . . . . 14
Nuclear Magnetic Resonance Relaxation Times of Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-11a . . . . . . . . . . . . . . . . . . 15
Nuclear Magnetic Resonance Relaxation Times of Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-11b . . . . . . . . . . . . . . . . . . 16
Capture Cross Section of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-12 . . . . . . . . . . . . . . . . . . . 18
Capture Cross Section of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-13 . . . . . . . . . . . . . . . . . . . 19
Capture Cross Section of Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-14 . . . . . . . . . . . . . . . . . . . 21
EPT* Propagation Time of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-15 . . . . . . . . . . . . . . . . . . . 22
EPT Attenuation of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-16 . . . . . . . . . . . . . . . . . . . 23EPT Propagation Time–Attenuation Crossplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-16
a . . . . . . . . . . . . . . . . . . 24
Gamma Ray
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arcVISION675* Gamma Ray—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-20 . . . . . . . . . . . . . . . . . . . . 39arcVISION825* Gamma Ray—8.25-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-21 . . . . . . . . . . . . . . . . . . . . 40
arcVISION900* Gamma Ray—9-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-22 . . . . . . . . . . . . . . . . . . . . 41
arcVISION475 Gamma Ray—4.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-23 . . . . . . . . . . . . . . . . . . . . 42
arcVISION675 Gamma Ray—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-24 . . . . . . . . . . . . . . . . . . . . 43
arcVISION825 Gamma Ray—8.25-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-25 . . . . . . . . . . . . . . . . . . . . 44
arcVISION900 Gamma Ray—9-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-26 . . . . . . . . . . . . . . . . . . . . 45
EcoScope* Integrated LWD Gamma Ray—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-27 . . . . . . . . . . . . . . . . . . . . 46
EcoScope Integrated LWD Gamma Ray—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-28 . . . . . . . . . . . . . . . . . . . . 47
Spontaneous Potent
ial
R weq Determination from ESSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-1 . . . . . . . . . . . . . . . . . . . . . . 49
R weq versus R w and Formation Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-2 . . . . . . . . . . . . . . . . . . . . . . 50
R weq versus R w and Formation Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-3 . . . . . . . . . . . . . . . . . . . . . . 51
Bed Thickness Correction—Open Hole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-
4 . . . . . . . . . . . . . . . . . . . . . . 53Bed Thickness Correction—Open Hole (Empirical) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-5 . . . . . . . . . . . . . . . . . . . . . . 54
Bed Thickness Correction—Open Hole (Empirical) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-6 . . . . . . . . . . . . . . . . . . . . . . 55
Densit
y
Porosity Effect on Photoelectric Cross Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dens-1. . . . . . . . . . . . . . . . . . . . 56
Apparent Log Density to True Bulk Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dens-2. . . . . . . . . . . . . . . . . . . . 57
Neutron
Dual-Spacing Compensated Neutron Tool Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-1 . . . . . . . . . . . . . . . . . . . . . 60
Contents
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Contents
adnVISION675* Azimuthal Density Neutron—6.75-in. Tool and 8-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-35 . . . . . . . . . . . . . . . . . . . 84adnVISION675 BIP Neutron—6.75-in. Tool and 8-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-36 . . . . . . . . . . . . . . . . . . . 85
adnVISION675 Azimuthal Density Neutron—6.75-in. Tool and 10-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-37 . . . . . . . . . . . . . . . . . . . 86
adnVISION675 BIP Neutron—6.75-in. Tool and 10-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-38 . . . . . . . . . . . . . . . . . . . 87
adnVISION825* Azimuthal Density Neutron—8.25-in. Tool and 12.25-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-39 . . . . . . . . . . . . . . . . . . . 88
CDN Compensated Density Neutron and adnVISION825s* Azimuthal Density Neutron—
8-in. Tool and 12-in. Borehole. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-40 . . . . . . . . . . . . . . . . . . . 89
CDN Compensated Density Neutron and adnVISION825s Azimuthal Density Neutron—8-in. Tool and 14-in. Borehole. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-41 . . . . . . . . . . . . . . . . . . . 90
CDN Compensated Density Neutron and adnVISION825s Azimuthal Density Neutron—
8-in. Tool and 16-in. Borehole. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-42 . . . . . . . . . . . . . . . . . . . 91
EcoScope* Integrated LWD BPHI Porosity—6.75-in. Tool and 8.5-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-43 . . . . . . . . . . . . . . . . . . . 93
EcoScope Integrated LWD BPHI Porosity—6.75-in. Tool and 9.5-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-44 . . . . . . . . . . . . . . . . . . . 94
EcoScope Integrated LWD TNPH Porosity—6.75-in. Tool and 8.5-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-45 . . . . . . . . . . . . . . . . . . . 95
EcoScope Integrated LWD TNPH Porosity—6.75-in. Tool and 9.5-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-46 . . . . . . . . . . . . . . . . . . . 96EcoScope Integrated LWD—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-47 . . . . . . . . . . . . . . . . . . . 98
Nuclear Magnetic Resonance
CMR* Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CM
R-1 . . . . . . . . . . . . . . . . . . . . 99
Resist
iv
ity L
aterolog
ARI* Azimuthal Resistivity Imager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-1 . . . . . . . . . . . . . . . . . . . . 101
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-2 . . . . . . . . . . . . . . . . . . . . 102High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-3 . . . . . . . . . . . . . . . . . . . . 103
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-
4 . . . . . . . . . . . . . . . . . . . . 104
Hi h R l ti A i th l L t l S d (HALS) RLl 5 105
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CHFR* Cased Hole Formation Resistivity Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-50. . . . . . . . . . . . . . . . . . . 121CHFR Cased Hole Formation Resistivity Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-51. . . . . . . . . . . . . . . . . . . 122
CHFR Cased Hole Formation Resistivity Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-52. . . . . . . . . . . . . . . . . . . 123
Resistiv ity Induction
AIT* Array Induction Imager Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RInd-1 . . . . . . . . . . . . . . . . . . 125
AIT Array Induction Imager Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Resistiv ity Electromagnetic
arcVISION475 and ImPulse 43 ⁄ 4-in. Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-11 . . . . . . . . . . . . . . . . . 131
arcVISION475 and ImPulse 43 ⁄ 4-in. Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-12 . . . . . . . . . . . . . . . . . 132
arcVISION475 and ImPulse 43 ⁄ 4-in. Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-13 . . . . . . . . . . . . . . . . . 133
arcVISION475 and ImPulse 43 ⁄ 4-in. Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-14 . . . . . . . . . . . . . . . . . 134
arcVISION675 63 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-15 . . . . . . . . . . . . . . . . . 135
arcVISION675 63 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-16 . . . . . . . . . . . . . . . . . 136
arcVISION675 63 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-17 . . . . . . . . . . . . . . . . . 137
arcVISION675 63 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-18 . . . . . . . . . . . . . . . . . 138
arcVISION675 63 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-19 . . . . . . . . . . . . . . . . . 139
arcVISION675 63 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-20 . . . . . . . . . . . . . . . . . 140
arcVISION675 63 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-21 . . . . . . . . . . . . . . . . . 141
arcVISION675 63 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-22 . . . . . . . . . . . . . . . . . 142
arcVISION825 81 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-23 . . . . . . . . . . . . . . . . . 143
arcVISION825 81 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-24 . . . . . . . . . . . . . . . . . 144
arcVISION825 81 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-25 . . . . . . . . . . . . . . . . . 145
arcVISION825 81⁄4-in Array Resistivity Compensated Tool—400 kHz REm-26 146
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arcVISION900 9-in. Array Resistivity Compensated Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-38 . . . . . . . . . . . . . . . . . 158arcVISION675, arcVISION825, and arcVISION900 Array Resistivity Compensated Tools—400 kHz . . . . . . . . . . . . . . . . REm-55 . . . . . . . . . . . . . . . . . 160
arcVISION and ImPulse Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-56 . . . . . . . . . . . . . . . . . 161
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 16-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-58 . . . . . . . . . . . . . . . . . 162
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 22-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-59 . . . . . . . . . . . . . . . . . 163
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 28-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-60 . . . . . . . . . . . . . . . . . 164
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 34-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-61 . . . . . . . . . . . . . . . . . 165
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 40-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-62 . . . . . . . . . . . . . . . . . 166
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz with Dielectric Assumption . . . . . . . . . . . REm-63 . . . . . . . . . . . . . . . . . 167
Formation Resistiv ity
Resistivity Galvanic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-1 . . . . . . . . . . . . . . . . . . . . . 168
High-Resolution Azimuthal Laterlog Sonde (HALS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-2 . . . . . . . . . . . . . . . . . . . . . 169
High-Resolution Azimuthal Laterlog Sonde (HALS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-3 . . . . . . . . . . . . . . . . . . . . . 170
geoVISION675* Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-10 . . . . . . . . . . . . . . . . . . . . 171geoVISION675 Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-11 . . . . . . . . . . . . . . . . . . . . 172
geoVISION675 Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-12 . . . . . . . . . . . . . . . . . . . . 173
geoVISION675 Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-13 . . . . . . . . . . . . . . . . . . . . 174
geoVISION825* 81 ⁄ 4-in. Resistivity-at-the-Bit Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-14 . . . . . . . . . . . . . . . . . . . . 175
geoVISION825 81 ⁄ 4-in. Resistivity-at-the-Bit Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-15 . . . . . . . . . . . . . . . . . . . . 176
geoVISION825 81 ⁄ 4-in. Resistivity-at-the-Bit Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-16 . . . . . . . . . . . . . . . . . . . . 177
geoVISION825 81 ⁄ 4-in. Resistivity-at-the-Bit Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-17 . . . . . . . . . . . . . . . . . . . . 178
arcVISION Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-31 . . . . . . . . . . . . . . . . . . . . 179
arcVISION and ImPulse Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-32 . . . . . . . . . . . . . . . . . . . . 180
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Litholog yDensity and NGS* Natural Gamma Ray Spectrometry Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-1 . . . . . . . . . . . . . . . . . . . 193
NGS Natural Gamma Ray Spectrometry Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-2 . . . . . . . . . . . . . . . . . . . 194
Platform Express* Three-Detector Lithology Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-3 . . . . . . . . . . . . . . . . . . . 196
Platform Express Three-Detector Lithology Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-4 . . . . . . . . . . . . . . . . . . . 197
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-5 . . . . . . . . . . . . . . . . . . . 198
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-6 . . . . . . . . . . . . . . . . . . . 200
Environmentally Corrected Neutron Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-7 . . . . . . . . . . . . . . . . . . . 202
Environmentally Corrected APS Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-8 . . . . . . . . . . . . . . . . . . . 204
Bulk Density or Interval Transit Time and Apparent Total Porosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-9 . . . . . . . . . . . . . . . . . . . 206
Bulk Density or Interval Transit Time and Apparent Total Porosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-10 . . . . . . . . . . . . . . . . . . 207
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-11 . . . . . . . . . . . . . . . . . . 209
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-12 . . . . . . . . . . . . . . . . . . 210
Porosity Sonic Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-1 . . . . . . . . . . . . . . . . . . . . 212
Sonic Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-2 . . . . . . . . . . . . . . . . . . . . 213
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-3 . . . . . . . . . . . . . . . . . . . . 214
APS Near-to-Array (APLC) and Near-to-Far (FPLC) Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-4 . . . . . . . . . . . . . . . . . . . . 216
Thermal Neutron Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-5 . . . . . . . . . . . . . . . . . . . . 217
Thermal Neutron Tool—CNT-D and CNT-S 21 ⁄ 2-in. Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-6 . . . . . . . . . . . . . . . . . . . . 218
adnVISION475 4.75-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-7 . . . . . . . . . . . . . . . . . . . . 219
adnVISION675 6.75-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-8 . . . . . . . . . . . . . . . . . . . . 220
adnVISION825 8.25-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-9 . . . . . . . . . . . . . . . . . . . . 221
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Density and APS Epithermal Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-25. . . . . . . . . . . . . . . . . . . 243Density, Neutron, and R xo Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-26. . . . . . . . . . . . . . . . . . . 245
Hydrocarbon Density Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-27. . . . . . . . . . . . . . . . . . . 246
Saturation
Porosity Versus Formation Resistivity Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-1. . . . . . . . . . . . . . . . . 247
Spherical and Fracture Porosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-2. . . . . . . . . . . . . . . . . 248
Saturation Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-3. . . . . . . . . . . . . . . . . 250
Saturation Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-4. . . . . . . . . . . . . . . . . 252
Graphical Determination of S w from S wt and S wb. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-5. . . . . . . . . . . . . . . . . 253
Porosity and Gas Saturation in Empty Hole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-6. . . . . . . . . . . . . . . . . 254
EPT Propagation Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-7. . . . . . . . . . . . . . . . . 255
EPT Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-8. . . . . . . . . . . . . . . . . 256
Capture Cross Section Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatCH-1 . . . . . . . . . . . . . . . . . 258
Capture Cross Section Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatCH-2 . . . . . . . . . . . . . . . . . 260RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 6.125-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatCH-3 . . . . . . . . . . . . . . . . . 262
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 9.875-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatCH-4 . . . . . . . . . . . . . . . . . 263
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 8.125-in. Borehole with 4.5-in. Casing at 11.6 lbm/ft . . . . SatCH-5 . . . . . . . . . . . . . . . . . 264
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 7.875-in. Borehole with 5.5-in. Casing at 17 lbm/ft . . . . . . SatCH-6 . . . . . . . . . . . . . . . . . 265
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 8.5-in. Borehole with 7-in. Casing at 29 lbm/ft . . . . . . . . . . . SatCH-7 . . . . . . . . . . . . . . . . . 266
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 9.875-in. Borehole with 7-in. Casing at 29 lbm/ft . . . . . . . . SatCH-8 . . . . . . . . . . . . . . . . . 267
Permeability
Permeability from Porosity and Water Saturation Perm-1 269
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PorosityForeword
This edition of the Schlumberger “chartbook” presents severalinnovations.
First, the charts were developed to achieve two purposes:
Correct raw measurements to account for environmental effects
Early downhole measurements were performed in rather uniform
conditions (vertical wells drilled through quasi-horizontal thick
beds, muds made of water with a narrow selection of additives,
and limited range of hole sizes), but today wells can be highly
deviated or horizontal, mud contents are diverse, and hole sizes
range from 2 to 40 in. Environmental effects may be large. In
addition, they compound. It is essential to correct for these effects
before the measurements are used.
Use environmentally corrected measurements for interpretation
Charts related to measurements that are no longer performedare not included in this chartbook. However, because many oil and
gas companies use logs acquired years or even decades ago, the
second chartbook, Historical Log Interpretation Charts, contains
these old charts.
Why publish charts on paper in our electronic age? It is true that
software may be more effective than pencil to derive results. Even
more so, this chartbook cannot cope with the complex well situations
that are encountered. Using software is the only way to proceed.
Thus, the chartbook has two primary functions: Training
The chartbook is essential for educating junior petrophysicists
about the different effects on the measurements. In the interpre-
tation process, the chartbook unveils the relationships between
the different parameters.
Sensitivity analysis
A chart gives the user a graphical idea of the sensitivity of an out-
put to the various inputs (see Chart Gen-1). The visual presenta-
tion is helpful for determining if an input parameter is critical.
The user can then focus on the most sensitive inputs.
Foreword
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Gen
General
Symbols Used in Log InterpretationGen-1
(former Gen-3)
di
dj
h
Adjacent bed
Zone of transition
orannulus
Flushedzone
Adjacent bed
(Bed thickness)
Mud
hmc
dh
Rm
Rs
Rs
Resistivity of the zone
Resistivity of the water in the zone
Water saturation in the zone
Rmc
Mudcake
Rmf
Sxo
Rxo
Rw
Sw
R t
Ri
Uninvadedzone
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General
Gen
Estimation of Formation Temperature with Depth
PurposeThis chart has a twofold purpose. First, a geothermal gradient can
be assumed by entering the depth and a recorded temperature at
that depth. Second, for an assumed geothermal gradient, if the tem-
perature is known at one depth in the well, the temperature at
another depth in the well can be determined.
Description
Depth is on the y-axis and has the shallowest at the top and the
deepest at the bottom. Both feet and meters are used, on the left
and right axes, respectively. Temperature is plotted on the x-axis,
with Fahrenheit on the bottom and Celsius on the top of the chart.
The annual mean surface temperature is also presented in
Fahrenheit and Celsius.
ExampleGiven: Bottomhole depth = 11,000 ft and bottomhole tempera-
ture = 200°F (annual mean surface temperature = 80°F).
Find: Temperature at 8,000 ft.
Answer: The intersection of 11,000 ft on the y-axis and 200°F
on the x-axis is a geothermal gradient of approximately
1.1°F/100 ft (Point A on the chart).
Move upward along an imaginary line parallel to the con-
structed gradient lines until the depth line for 8,000 ft isintersected. This is Point B, for which the temperature
on the x-axis is approximately 167°F.
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General
Gen
General
Estimation of Formation Temperature with DepthGen-2
(former Gen-6)
27 50 75 100 125 150 175
16 25 50 75 100 125 150 175
Temperature (°C)
Temperature gradient conversions: 1°F/100 ft = 1.823°C/100 m 1°C/100 m = 0.5486°F/100 ft
Depth
(thousands
of feet)
Depth(thousandsof meters)
Annual meansurface temperature
5
10
15
20
1
2
3
4
5
6
0.6 0.8 1.0 1.2 1.4 1.6°F/100 ft
1.09 1.46 1.82 2.19 2.55 2.92°C/100 m
B
A
Geothermal gradient
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General
Gen
Estimation of Rmf and Rmc
Fluid Properties Gen-3
(former Gen-7)
PurposeDirect measurements of filtrate and mudcake samples are preferred.
When these are not available, the mud filtrate resistivity (Rmf ) and
mudcake resistivity (Rmc) can be estimated with the following
methods.
Description
Method 1: Lowe and Dunlap
For freshwater muds with measured values of mud resistivity (R m)
between 0.1 and 2.0 ohm-m at 75°F [24°C] and measured values of mud density (ρm) (also called mud weight) in pounds per gallon:
Method 2: Overton and Lipson
For drilling muds with measured values of Rm between 0.1 and
10.0 ohm-m at 75°F [24°C] and the coefficient of mud (K m) given
as a function of mud weight from the table:
ExampleGiven: Rm = 3.5 ohm-m at 75°F and mud weight = 12 lbm/gal
[1,440 kg/m3].
Find: Estimated values of Rmf and Rmc.
Answer: From the table, K m = 0.584.
Rmf = (0.584)(3.5)1.07 = 2.23 ohm-m at 75°F.
Rmc = 0.69(2.23)(3.5/2.23)2.65 = 5.07 ohm-m at 75°F.
log .= . .R
Rmf
mm
− ×( )0 396 0 0475 ρ
R K R
R RR
R
mf m m
mc mf m
mf
= ( )
= ( )
1 07
2 65
0 69
.
.
. .
Mud Weight
lbm/gal kg/m3 Km
10 1,200 0.847
11 1,320 0.708
12 1,440 0.584
13 1,560 0.488
14 1,680 0.412
16 1,920 0.380
18 2,160 0.350
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10 20 50 100 200 500 1,000 2,000 5,000 10,000 20,000 50,000 100,000 300,000
2.0
1.5
1.0
0.5
0
–0.5
2.0
1.0
0
Total solids concentration (ppm or mg/kg)
Multiplier
† Multipliers that do not vary appreciably for low concentrations
Li (2.5)†
NH4 (1.9)†
Na and CI (1.0)
NO3 (0.55)†
Br (0.44)†
I (0.28)†
OH (5.5)†
Mg
Mg
K
K
Ca
Ca
CO3
CO3
SO4
SO4
HCO3
HCO3
General
Gen
Equivalent NaCl Salinity of SaltsGen-4
(former Gen-8)
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Gen
General
Concentration of NaCl SolutionsGen-5
g/L at
77°F
ppm grains/gal
at 77°F °F/100 ft °C/100 ft °API
Oil GravityConcentrations of NaCl Solutions
Temperature Gradient
Conversion
Specific
gravity (sg) at 60°F
Density of NaCl
solution at
77°F [25°C]
0.15 150
200
300
400
500
600
800
1,000
1,500
2,000
3,000
4,000
5,000
6,000
8,000
10,000
101.00
1.005
2.0
2.5
3.0
0.60
0.62
0.64
0.66
0.68
0.70
0.72
0.74
0.76
0.78
0.80
0.82
0.84
0.860.88
0.900.920.940.960.98
3.5
1.1
1.2
1.3
1.4
1.5
1.6
1.7
100
90
80
70
60
50
40
30
20
1.8
1.9
2.0
12.5
15
20
25
30
40
50
60708090100
125
150
200
250
300
400
500
600
0.2
0.3
0.4
0.5
0.6
0.8
1.0
1.5
2
3
4
5
6
8
10
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Gen
General
Resistivity of NaCl Water Solutions
PurposeThis chart has a twofold purpose. The first is to determine the resis-
tivity of an equivalent NaCl concentration (from Chart Gen-4) at a
specific temperature. The second is to provide a transition of resis-
tivity at a specific temperature to another temperature. The solution
resistivity value and temperature at which the value was determined
are used to approximate the NaCl ppm concentration.
Description
The two-cycle log scale on the x-axis presents two temperature
scales for Fahrenheit and Celsius. Resistivity values are on the left
four-cycle log scale y-axis. The NaCl concentration in ppm and
grains/gal at 75°F [24°C] is on the right y-axis. The conversion
approximation equation for the temperature (T) effect on the
resistivity (R) value at the top of the chart is valid only for the
temperature range of 68° to 212°F [20° to 100°C].
Example OneGiven: NaCl equivalent concentration = 20,000 ppm.
Temperature of concentration = 75°F.
Find: Resistivity of the solution.
Answer: Enter the ppm concentration on the y-axis and the tem-
perature on the x-axis to locate their point of intersec-
tion on the chart. The value of this point on the left
y-axis is 0.3 ohm-m at 75°F.
Example TwoGiven: Solution resistivity = 0.3 ohm-m at 75°F.
Find: Solution resistivity at 200°F [93°C].
Answer 1: Enter 0.3 ohm-m and 75°F and find their intersection
on the 20,000-ppm concentration line. Follow the line to
the right to intersect the 200°F vertical line (interpolate
between existing lines if necessary). The resistivity value
for this point on the left y-axis is 0.115 ohm-m.
Answer 2: Resistivity at 200°F = resistivity at 75°F×
[(75 + 6.77)/
(200 + 6.77)] = 0.3 × (81.77/206.77) = 0.1186 ohm-m.
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General
Gen
Resistivity of NaCl Water SolutionsGen-6
(former Gen-9)
Resistivity
of solution
(ohm-m)
ppm
10
8
6
5
4
3
2
1
0.8
0.6
0.5
0.4
0.3
0.2
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0 7 0 0 8 0 0
1 , 0 0 0 1 , 2 0 0 1 , 4 0 0 1 , 7 0 0 2 , 0 0 0
3 , 0 0 0
4 , 0 0 0
5 , 0 0 0 6 , 0 0 0 7 , 0 0 0 8 0
Conversion approximated by R2 = R1 [(T1 + 6.77)/(T2 + 6.77)]°F or R2 = R1 [(T1 + 21.5)/(T2 + 21.5)]°C
NaClconcentration
(ppm or
grains/gal)
grains/galat 75°F
10
15
20
25
30
4050
100
150
200250
300
400
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General
Gen
Density of Water and Hydrogen Index of Water and HydrocarbonsGen-7
1.20
Pressure NaCl
14.7 psi1,000 psi7,000 psi
25 50 100
Temperature (°C)
Temperature (°F)
Hydrogen Index of Salt Water
Hydrogen Index of Live Hydrocarbons and Gas
Salinity (kppm or g/kg)
150 200
0.8544040030020010040
Hydrocarbons
Water
0.90
0.95
1.00
1.05
1.10
1.15
1.05
1.2
1.0
0.6
0.8
1.00
0.95
0.90
0.850 50 100 150 200 250
Waterdensity(g/cm3)
Hydrogenindex
Hydrogenindex
2 5 0 , 0 0 0 p p m
2 0 0 , 0 0 0 p p m
1 5 0 , 0 0 0 p p m
1 0 0 ,0 0 0 p p m
5 0 ,0 0 0 p p m
D i s t i l l e d w a t e r
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General
Gen
Density and Hydrogen Index of Natural GasGen-8
0.3
0.4
0.5
17,500
15,00012,500
10,000
7,500
Pressure (psi)
Gas gravity = 0.65
Gas
density
Gas pressure × 1,000 (psia)
0
0.1
0.2
0.3
0.7
Hgas
Gas tempera ture
(°F)
Gas gravity = 0.6(Air = 1.0)
0.6100
150
200250300350
0.5
0.4
0.3
0.2
0.1
0
0 2 4 6 8 10
Gas
density(g/cm3)
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General
Gen
General
Sound Velocity of HydrocarbonsGen-9
Gas gravity = 0.65
Natural Gas
50 100 150 200 250 300 3500
1,000
2,000
3,000
4,000
5,000 200
250
30017,500
15,000
12,500
10,000
7,500
5,000
2,500
14.7
400
500
1,000
2,000
Temperature (°C)
Pressure (psi)
Tempera ture (°F)
Soundvelocity
(ft /s)
Soundslowness
(µs /ft)
0 50 100 150 200
© Schlumberger
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Gas Effect on Compressional Slowness
General
Gen-9a
Gen
1000
200
100
200 µs/ft
110 µs/ft
90 µs/ft
70 µs/ft
50
∆ tc(µs/ft)
We tsand
Sandstone
80604020
Wood’s law (e = 5) Power law (e = 3)
Liquid saturation (%)
© Schlumberger
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General
Gas Effect on Acoustic VelocitySandstone and Limestone
Gen-9b
Limestone
Sandstone
25
00
5
10
10
15
20
20
25
30 40
20
15
Porosi ty (p.u.)
Velocity(1,000 × ft/s)
Vp
Vs
No gasGas bearing
No gasGas bearing
Gen
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General
Gen
PurposeLongitudinal (Bulk) Relaxation Time of Pure Water
This chart provides an approximation of the bulk relaxation time
(T1) of pure water depending on the temperature of the water
DescriptionLongitudinal Relaxation Time
The chart relation is for pure water—the additives in drilling fluids
reduce the relaxation time (T1) of water in the invaded zone The
Nuclear Magnetic Resonance Relaxation Times of WaterGen-10
Longitudinal (Bulk) RelaxationTime of Water
Temperature (°C)
Relaxation time (s)
100
10
1.0
0.1
0.0120 60 100 140 180
T1
Transverse (Bulk and Diffusion)Relaxation Time of Water
Temperature (°C)
Relaxation time (s)
100
10
1.0
0.1
0.0120 60 100 140 180
T2
(TE = 0.2 ms)
T2 (TE = 0.32 ms)
T2 (TE = 1 ms)
T2 (TE = 2 ms)
© Schlumberger
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General
Gen
Nuclear Magnetic Resonance Relaxation Times of HydrocarbonsGen-11a
Transverse (Bulk and Diffusion) Relaxation Time of Crude Oil
T1
(s)
Longitudinal (Bulk) RelaxationTime of Crude Oil
Viscosity (cp)
0.1 1 10 100 1,000 10,000 100,000
0.001
0.01
0.1
1
10
0.0001
T2 (s)
Viscosity (cp)
0.1 1 10 100 1,000 10,000 100,000
0.001
0.01
0.1
1
10
0.0001
Diffusion(cm2 /s)
Hydrocarbon Diffusion Coefficient10–3
10–4
10–5
0
Oil (9° at 20°C)
Oil (40° at 20°C)
Diffusion(10–5 cm2 /s)
Water Diffusion Coefficient
10
15
20
Light oil: 45°–60° API 0.65–0.75 g/cm3
Medium oil: 25°–40° API 0.75–0.85 g/cm3
Heavy oil: 10°–20° API 0.85–0.95 g/cm3
TE = 0.2 msTE = 0.32 msTE = 1 msTE = 2 ms
T1
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General
Nuclear Magnetic Resonance Relaxation Times of HydrocarbonsGen-11b
0.6
0.8
1.0
1.2
Hydrogenindex
Hydrogen Index of Live Hydrocarbons and Gas
0
2
4
6
0 6,000 9,000
25°C75°C125°C175°C
Longitudinal (Bulk) RelaxationTime of Methane
Pressure (psi)
3,000 12,000
10
8
Transverse (Bulk and Diffusion)Relaxation Time of Methane
100
1
10
T2 (s)TE 0 32
TE = 0.2 ms
T1 (s)
10
15
20
25
30
35
50 100 150 200
Methane Diffusion Coefficient
Diffusion(10–4 cm2 /s)
Temperature (°C)
1,600 psi
3,000
0
0
5
8,300
15,500
22,800
3,900
4,500
Gen
General
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General
Capture Cross Section of NaCl Water Solutions
GenPurposeThe sigma value (Σ w ) of a saltwater solution can be determined from
this chart. The sigma water value is used to calculate the water satu-
ration of a formation.
Description
Charts Gen-12 and Gen-13 define sigma water for pressure condi-
tions of ambient through 20,000 psi [138 MPa] and temperatures
from 68° to 500°F [20° to 260°C]. Enter the appropriate chart for
the pressure value with the known water salinity on the y-axis andmove horizontally to intersect the formation temperature. The sigma
of the formation water for the intersection point is on the x-axis.
ExampleGiven: Water salinity = 125,000 ppm, temperature = 68°F at
ambient pressure, and formation temperature = 190°F
at 5,000 psi.
Find: Σ w at ambient conditions and Σ w of the formation.
Answer: Σ w = 69 c.u. and Σ w of the formation = 67 c.u.
If the sigma water apparent (Σ wa ) is known from a clean water
sand, then the salinity of the formation can be determined by enter-
ing the chart from the sigma water value on the x-axis to intersectthe pressure and temperature values.
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General
Gen
A m b i e
n t
2 0 0 °
F [ 9 3
° C ]
6 8 ° F
[ 2 0 °
C ]
4 0 0 °
F [ 2 0 5 °
C ]
3 0 0 °
F [ 1 5
0 ° C ]
2 0 0 °
F [ 9 3
° C ]
6 8 ° F
[ 2 0 °
C ]
4 0 0 °
F [ 2 0 5 °
C ]
3 0 0 °
F [ 1 5
0 ° C ]
2 0 0 °
F [ 9 3
° C ]
6 8 ° F
[ 2 0 °
C ]
1 , 0 0 0
p s i [ 6 . 9 M P a ]
0 p s i [ 3
4 M P a ]
300
275
250
225
200
175
150
125
100
75
50
25
0
100
75
50
300
275
250
225
200
300
275
250
225
200
300
275
250
225
200
125
150
175175
150
125
Equivalent water salinity(1,000 × ppm NaCl)
Capture Cross Section of NaCl Water SolutionsGen-12
(former Tcor-2a)
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General
Capture Cross Section of NaCl Water SolutionsGen-13
(former Tcor-2b)
Gen
1 0 , 0 0 0 p s i
[ 6 9 M P a ]
5 0 0 ° F [
2 6 0 ° C ]
4 0 0 ° F [
2 0 5 ° C ]
3 0 0 ° F [
1 5 0 ° C ]
2 0 0 ° F [
9 3 ° C
]
6 8 ° F
[ 2 0 ° C ]
4 0 0 ° F [
2 0 5 ° C ]
3 0 0 ° F [
1 5 0 ° C ]
2 0 0 ° F [
9 3 ° C
]
6 8 ° F
[ 2 0 ° C ]
4 0 0 ° F [
2 0 5 ° C ]
3 0 0 ° F [
1 5 0 ° C ]
2 0 0 ° F [
9 3 ° C
]
6 8 ° F
[ 2 0 ° C ]
1 5 , 0 0 0 p
s i [ 1 0 3
M P a ]
ps i [ 1
3 8 M P a ]
300
275
250
225
200
175
150
125
100
75
50
25
0
100
75
50
300
275
250
225
200
300
275
250
225
200
300
275
250
225
200
Equivalent water salinity(1,000 × ppm NaCl)
125
150
175175
150
125
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PurposeSigma hydrocarbon (Σh) for gas or oil can be determined by using
this chart. Sigma hydrocarbon is used to calculate the water satura-
tion of a formation.
DescriptionOne set of charts is for measurement in metric units and the other
is for measurements in “customary” oilfield units.
For gas, enter the background chart of a chart set with the reser-
voir pressure and temperature. At that intersection point move left
to the y-axis and read the sigma of methane gas.For oil, use the foreground chart and enter the solution gas/oil
ratio (GOR) of the oil on the x-axis. Move upward to intersect the
appropriate API gravity curve for the oil. From this intersection
point, move horizontally left and read the sigma of the oil on
the y-axis.
ExampleGiven: Reservoir pressure = 8,000 psi, reservoir temperature =
300°F, gravity of reservoir oil = 30°API, and solution
GOR = 200.
Find: Sigma gas and sigma oil.
Answer: Sigma gas = 10 c.u. and sigma oil = 21.6 c.u.
General
Gen
Capture Cross Section of Hydrocarbons
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General
Gen
Capture Cross Section of HydrocarbonsGen-14
(former Tcor-1)
20.0
17.5
15.0
12.5
10.0
7.5
5.0
2.5
0
6 8
1 2 5
2 0 0
3 0 0
4 0 0
5 0 0
Reservoir pressure (psia)
0 4,000 8,000 12,000 16,000 20,000
Methane
Temperature (°F)
Σh (c.u.)
Customary
10 100 1,000 10,000
Solution GOR (ft3 /bbl)
Liquid hydrocarbons
C o n d e n s a t e
30°, 40°, and 50°API
20° and 60°API
16
18
20
22
Σh (c.u.)
20.0
Reservoir pressure (mPa)
0 14 28 41 55 69 83 97 110 124 138
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General
EPT* Propagation Time of NaCl Water SolutionsGen-15
(former EPTcor-1)
90
80
70
60
50
40
30
tpw (ns/m)
120°C250°F
100°C200°F
80°C175°F
40°C100°F
150°F 60°C
75°F 20°C
125°F
Gen
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General
Gen
EPT* Attenuation of NaCl Water SolutionsGen-16
(former EPTcor-2)
0 50 100 150 200 250
Equivalent water salinity (kppm or g/kg NaCl)
–40
–60
–80
120°C250°F100°C200°F 80°C175°F
40°C100°F
150°F 60°C
75°F 20°C
125°F
5,000
4,000
3,000
2,000
1,000
0
Attenuation,Aw
(dB/m)
EPT-D Spreading Loss
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General
Gen
EPT* Propagation Time–Attenuation CrossplotSandstone Formation at 150°F [60°C]
Gen-16a
1,000
900
800
700
600
500
400
300
200
100
0
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
1.0
40 50302010
2.0
5.010.0
50.0
Attenuation(dB/m)
tpl (ns/m)
Sandstone at 150°F [60°C]
Rmfa from EPT log (ohm-m)
E P T
p o r o
s i t y
( φ E P T )
0.02 0.05
0.1
0.2
0.5
*Mark of Schlumberger
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Gamma Ray—Wireline
Scintillation Gamma Ray—33 ⁄ 8- and 111 ⁄ 16-in. ToolsGamma Ray Correction for Hole Size and Barite Mud Weight
GR–1(former GR-1)
10.0
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
Correctionfactor
t (g/cm2)
0 5 10 15 20 25 30 35 40
Scintillation Gamma Ray
33 ⁄ 8-in. tool, centered
111 ⁄ 16-in. tool, centered
33 ⁄ 8-in. tool, eccentered
111 ⁄ 16-in. tool, eccentered
GR
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Gamma Ray—Wireline
Scintillation Gamma Ray—33 ⁄ 8- and 111 ⁄ 16-in. ToolsGamma Ray Correction for Barite Mud in Various-Size Boreholes
GR-2(former GR-2)
1.2
1.0
0.8
0.6
0.4
0.2
0
Mud weight (lbm/gal)
7 8 9 10 11 12 13 14 15 16 17 18 19 20
1.2
1.0
0.8
0.6
0.4
0.2
0
Fbh
Bmud
33 ⁄ 8-in. tool, centered
111 ⁄ 16-in. tool, centered
33 ⁄ 8-in. tool, eccentered
111 ⁄ 16-in. tool, eccentered
33 ⁄ 8-in. tool
111 ⁄ 16-in. tool
GR
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Gamma Ray—Wireline
Scintillation Gamma Ray—33 ⁄ 8- and 111 ⁄ 16-in. ToolsBorehole Correction for Cased Hole
GR-3(former GR-3)
10.0
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
Correctionfactor
0 5 10 15 20 25 30 35 40
Scintillation Gamma Ray
33 ⁄ 8-in. tool
111 ⁄ 16-in. tool
GR
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Gamma Ray—LWD
SlimPulse* and E-Pulse* Gamma Ray ToolsBorehole Correction for Open Hole
GR-6
11
10
9
8
7
6
5
4
3
2
1
0
Correctionfactor
6-in. bit7-in. bit
8.5-in. bit
9.875-in. bit
12.25-in. bit
13.5-in. bit
17.5-in. bit
GR
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Gamma Ray—LWD
ImPulse* Gamma Ray— 4.75-in. ToolBorehole Correction for Open Hole
GR-7
1.75
1.50
1.25
1.00
0.75
Correctionfactor
8.5-in. bit
7-in. bit
6-in. bit
GR
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Gamma Ray—LWD
PowerPulse* and TeleScope* Gamma Ray—6.75-in. ToolsBorehole Correction for Open Hole
GR-9
3.00
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1 00
Correc tionfac tor
PowerPulse and TeleScope Gamma Ray
8.5-in. bit
8.75-in. bit
10.625-in. bit
9.875-in. bit
12.25-in. bit
GR
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Gamma Ray—LWD
PowerPulse* Gamma Ray—8.25-in. Normal-Flow ToolBorehole Correction for Open Hole
GR-10
5.00
4.75
4.50
4.25
4.00
3.75
3.50
3.25
3.00
2.75
2 50
Correction
factor
9.875-in. bit
12.25-in. bit
13.5-in. bit
17.5-in. bit
10.625-in. bit
14.75-in. bit
GR
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Gamma Ray—LWD
PowerPulse* Gamma Ray—8.25-in. High-Flow ToolBorehole Correction for Open Hole
GR-11
4.25
4.00
3.75
3.50
3.25
3.00
2.75
2.50
2.25
2.00
1.75
Correctionfactor
17.5-in. bit
14.75-in. bi t
13.5-in. bit
12.25-in. bit
10.625-in. bit
9.875-in. bit
GR
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Gamma Ray—LWD
PowerPulse* Gamma Ray—9-in. ToolBorehole Correction for Open Hole
GR-12
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
2.50
Correctionfactor 17.5-in. bit
14.75-in. bit
13.5-in. bit
12.25-in. bit
10.625-in. bit
22-in. bit
GR
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Gamma Ray—LWD
PowerPulse* Gamma Ray—9.5-in. Normal-Flow ToolBorehole Correction for Open Hole
GR-13
8.00
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
Correctionfactor
17.5-in. bit
14.75-in. bit
13.5-in. bit
12.25-in. bit
10.625-in. bit
22-in. bi t
GR
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Gamma Ray—LWD
PowerPulse* Gamma Ray—9.5-in. High-Flow ToolBorehole Correction for Open Hole
GR-14
8.00
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
2.50
2.00
Correctionfactor
10.625-in. bit
12.25-in. bit
13.5-in. bit
14.75-in. bit
17.5-in. bit
22-in. bit
GR
G R LWD
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Gamma Ray—LWD
geoVISION675* GVR* Gamma Ray—6.75-in. ToolBorehole Correction for Open Hole
GR-15
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
Correctionfactor
8.5-in. bit8.75-in. bit
9.875-in. bit
10.625-in. bit
12.25-in. bit
GR
G R LWD
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Gamma Ray—LWD
RAB* Gamma Ray—8.25-in. ToolBorehole Correction for Open Hole
GR-16
3.00
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
Correctionfactor
9.875-in. bit
10.625-in. bit
12.25-in. bit
13.5-in. bit
14.75-in. bit
17.5-in. bit
GR
G R LWD
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Gamma Ray—LWD
arcVISION475* Gamma Ray—4.75-in. ToolBorehole Correction for Open Hole
GR-19
1.75
1.50
1.25
1.00
0.75
Correctionfactor
8.5-in. bit
7-in. bit
6-in. bit
GR
G R LWD
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Gamma Ray—LWD
arcVISION675* Gamma Ray—6.75-in. ToolBorehole Correction for Open Hole
GR-20
3.50
3.25
3.00
2.75
2.50
2.25
1.75
2.00
1.50
1.25
1.00
0.75
0.50
Correctionfactor
8.5-in. bit
8.75-in. bit
9.875-in. bit
10.625-in. bit
12.25-in. bit
GR
Gamma Ray LWD
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Gamma Ray—LWD
arcVISION825* Gamma Ray—8.25-in. ToolBorehole Correction for Open Hole
GR-21
3.00
2.75
2.50
2.25
2.00
1.50
1.75
1.25
1.00
0.75
0.50
Correctionfactor
9.875-in. bit
10.625-in. bit
12.25-in. bit
13.5-in. bit
14.75-in. bit
17.5-in. bit
GR
Gamma Ray LWD
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Gamma Ray—LWD
arcVISION900* Gamma Ray—9-in. ToolBorehole Correction for Open Hole
GR-22
5.5
5.0
4.5
4.0
3.5
2.5
3.0
2.0
1.5
1.0
0.5
Correctionfactor
10.625-in. bit
12.25-in. bit
13.5-in. bit
14.75-in. bit
17.5-in. bit
22-in. bit
GR
Gamma Ray LWD
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Gamma Ray—LWD
arcVISION475* Gamma Ray—4.75-in. ToolPotassium Correction for Open Hole
GR-23
100
90
80
70
60
40
50
30
20
10
0
Correctionsubtracted for 5-wt%potassium
(gAPI)
8.3 ppg
9 ppg10 ppg
12 ppg14 ppg
16 ppg18 ppg
20 ppg
GR
Gamma Ray—LWD
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Gamma Ray—LWD
arcVISION675* Gamma Ray—6.75-in. ToolPotassium Correction for Open Hole
GR-24
50
45
40
35
30
20
25
15
10
5
0
Correctionsubtractedfor 5-wt%potassium
(gAPI)
9 ppg
8.3 ppg
10 ppg
12 ppg
14 ppg
16 ppg
18 ppg
20 ppg
GR
Gamma Ray—LWD
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Gamma Ray LWD
arcVISION825* Gamma Ray—8.25-in. ToolPotassium Correction for Open Hole
GR-25
100
90
80
70
60
40
50
30
20
10
0
Correctionsubtractedfor 5-wt%potassium
(gAPI)
10 ppg
9 ppg
8.3 ppg
12 ppg
14 ppg
16 ppg
18 ppg
20 ppg
GR
Gamma Ray—LWD
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Gamma Ray LWD
arcVISION900* Gamma Ray—9-in. toolPotassium Correction for Open Hole
GR-26
120
100
80
60
40
20
0
Correctionsubtractedfor 5-wt%potassium
(gAPI)
10 ppg
9 ppg
8.3 ppg
12 ppg
14 ppg
16 ppg
18 ppg
20 ppg
GR
Gamma Ray—LWD
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Gamma Ray LWD
EcoScope* Integrated LWD Gamma Ray—6.75-in. ToolBorehole Correction for Open Hole
GR-27
3.00
2.75
2.50
2.25
2.00
1.50
1.75
1.25
1.00
0.75
0.50
Correctionfactor
9.875-in. bit
10.625-in. bit
12.25-in. bit
8.5-in. bit
8.75-in. bit
GR
Gamma Ray–Wireline
Gamma Ray—LWD
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50
45
40
35
30
20
25
15
10
5
0
Correc tionsubtrac tedfor 5-wt%potassium
(gAPI)
9 ppg
8.3 ppg
10 ppg
12 ppg
14 ppg
16 ppg
18 ppg
20 ppg
Gamma Ray Wireline
GR
Gamma Ray LWD
EcoScope* Integrated LWD Gamma Ray—6.75-in. ToolPotassium Correction for Open Hole
GR-28
Spontaneous Potential—Wireline
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p
SP
Rweq Determination from ESSP
Purpose
This chart and nomograph are used to calculate the equivalent for-mation water resistivity (R weq) from the static spontaneous potential
(ESSP) measured in clean formations. The value of R weq is used in
Chart SP-2 to determine the resistivity of the formation water (R w ).
R w is used in Archie’s water saturation equation.
DescriptionEnter the chart with ESSP in millivolts on the x-axis and move
upward to intersect the appropriate temperature line. From the
intersection point move horizontally to intersect the right y-axis forRmfeq /R weq. From this point, draw a straight line through the equiva-
lent mud filtrate resistivity (Rmfeq) point on the Rmfeq nomograph to
intersect the value of R weq on the far-right nomograph.
The spontaneous potential (SP) reading corrected for the effect
of bed thickness (ESPcor) from Chart SP-4 can be substituted for ESSP.
Example
First determine the value of Rmfeq:
If Rmf at 75°F is greater than 0.1 ohm-m, correct Rmf
to the formation temperature by using Chart Gen-6,
and use Rmfeq = 0.85Rmf .
If Rmf at 75°F is less than 0.1 ohm-m, use Chart SP-2
to derive a value of Rmfeq at formation temperature.
Given: ESSP = –100 mV at 250°F and resistivity of the mud
filtrate (Rmf ) = 0.7 ohm-m at 100°F, converted to 0.33
at 250°F.
Find: R weq at 250°F.
Answer: Rmfeq = 0.85Rmf = 0.85 × 0.33 = 0.28 ohm-m.
Draw a straight line from the point on the Rmfeq /R weq line
that corresponds to the intersection of ESSP = –100 mV
and the interpolated 250°F temperature curve through
the value of 0.28 ohm-m on the Rmfeq line to the R weq line
to determine that the value of R weq is 0.025 ohm-m.
The value of Rmfeq /R weq can also be determined from theequation
ESSP = K c log(Rmfeq /R weq),
where K c is the electrochemical spontaneous potential
coefficient:
K c = 61 + (0.133 × Temp°F)
K c = 65 + (0.24 × Temp°C).
Spontaneous Potential—Wireline
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p
SP
Rweq Determination from ESSPSP-1
(former SP-1)
0.01
0.02
0.04
0.06
0.1
0.2
0.4
0.001
0.005
0.01
0.02
0.05
Rmfeq
(ohm-m)
Rmfeq /Rweq
Rmf /Rw
Rweq
(ohm-m)
0.3
0.4
0.6
0.8
1
2
4
0.3
0.4
0.5
0.6
0.8
1
2
3
4
Spontaneous Potential—Wireline
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Rweq versus Rw and Formation TemperatureSP-2
(customary, former SP-2)
0.001
0.002
0.005
0.01
0.02
0.05
0.1
0.2
Rweq or Rmfeq
(ohm-m)
500°F400°F
300°F
200°F
150°F
100°F
75°F
Saturation
4 0 0 ° F
5 0 0 ° F
p
SP
Spontaneous Potential—Wireline
Spontaneous Potential—Wireline
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pp
SP
Rweq versus Rw and Formation TemperatureSP-3
(metric, former SP-2m)
0.001
0.002
0.005
0.01
0.02
0.05
0.1
0.2
Rweq or Rmfeq
(ohm-m)
250°C200°C
150°C
100°C
75°C
50°C
25°C
Saturation
2 0 0°C
2 5 0 ° C
Spontaneous Potential—Wireline
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Bed Thickness Correction—Open Hole
SP
Purpose
Chart SP-4 is used to correct the SP reading from the well log forthe effect of bed thickness. Generally, water sands greater than
20 ft in thickness require no or only a small correction.
DescriptionChart SP-4 incorporates correction factors for a number of condi-
tions that can affect the value of the SP in water sands.
The appropriate chart is selected on the basis of resistivity, inva-
sion, hole diameter, and bed thickness. First, select the row of charts with the most appropriate value of the ratio of the resistivity of shale
(Rs) to the resistivity of mud (Rm). On that row, select a chart for no
invasion or for invasion for which the ratio of the diameter of invasion
to the diameter of the wellbore (d i /dh) is 5. Enter the x-axis with
the value of the ratio of bed thickness to wellbore diameter (h/dh).
Move upward to intersect the appropriate curve of the ratio of the
true formation resistivity to the resistivity of the mud (R t /Rm) for
no invasion or the ratio of the resistivity of the flushed zone to the
resistivity of the mud (R xo /Rm) for invaded zones, interpolatingbetween the curves as necessary. Read the ratio of the SP read from
the log to the corrected SP (ESP /ESPcor) on the y-axis for the point of
intersection. Calculate ESPcor = ESP /(ESP /ESPcor). The value of ESPcor
can be used in Chart SP-1 for ESSP.
Spontaneous Potential-Wireline
Spontaneous Potential—Wireline
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SP
Bed Thickness Correction—Open HoleSP-4
(former SP-3)
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
ESP /ESPcor
ESP /ESPcor
Rs
Rm
= 1
Rs
Rm
= 5
Rxo = 0.2R t Rxo = R t
h/dh h/dh
Rxo = 5R t
Invasion, di /dh = 5No Invasion
10
52
20
50
100
200
500
10
5
21
0.5
20
50
100
200500
10
52
1
20
50
100200
500
10
5
2
10.5
20
50
100
200
10
52 1
0.5
20
50
100
200
Rxo /Rm Rxo /Rm Rxo /Rm
Rxo /RmRxo /Rm Rxo /Rm
R t /Rm
R t /Rm
21
1
2
50
10
20
5
0.5
0.2
0.1
100
10
20
50
100
200
5
10
5
2
1
0.5
0.2
20
50
100200
h/dh h/dh
Spontaneous Potential—Wireline
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Bed Thickness Correction—Open Hole (Empirical)SP-5
(customary, former SP-4)
ESSP
(%)
Correctionfactor
1.0
1.5
2.0
2.5
3.0
3.5
4.0
5.0
5
20
50
100
200
di (in.)
3 0
3
5 3 5
4 0
4 0
3 0
3 0
3 0
3 0
2 0
8-in. Hole; 33 ⁄ 8-in. Tool, Centered
Ri
Rm
100
90
80
70
60
50
40
30
20
SP
Spontaneous Potential—Wireline
Spontaneous Potential—Wireline
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SP
Bed Thickness Correction—Open Hole (Empirical)SP-6
(metric, former SP-4m)
0 .5
200-mm Hole; 86-mm Tool, Centered
ESSP
(%)
Correctionfactor
100
90
80
70
60
50
40
30
20
1.0
1.5
2.020
5
50
100
200
2.5
3.0
3.5
4.0
5.0
di (m)
Ri
Rm
0 . 7 5
0 . 7 5 0 . 7 5
0 . 7 5 0 . 7 5
0 . 8
0 . 8 8 1 . 0
1 . 0
General
Density—Wireline, LWD
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1 2 3
Quar tz Dolomite Calci te
GasWa ter
4 5 0.5 0.4 0.3 0.2 0.1 06
Pe φ tPorosity Effect on Pe
Matrix φ t 100% H2O 100% CH4
Quartz0.00 1.81 1.81
0.35 1.54 1.76
Calcite0.00 5.08 5.08
0.35 4.23 4.96
Dolomite0.00 3.14 3.14
0.35 2.66 3.07
Specific — 1.00 0.10gravity
Porosity Effect on Photoelectric Cross SectionDens-1
Purpose
This chart and accompanying table illustrate the effect that porosity,matrix, formation water, and methane (CH4) have on the recorded
photoelectric cross section (Pe).
Enter the chart with the total porosity (φt) from the log and move
downward to intersect the angled line. From this point moveto the left and intersect the line representing the appropriate matrix
material: quartz, dolomite, or calcite minerals. From this intersection
move upward to read the correct Pe.
Dens
© Schlumberger
Density—Wireline, LWD
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Dens
Apparent Log Density to True Bulk DensityDens-2
Magnesium
Dolomite
Sandstone + water
Low-pressure gasor air in pores
Sands tone
Sylvite (KCI)
Aluminum
Salt (NaCI)
Add correc tion
from y-axis to ρlog
to obtain true
bulk density, ρb
0.14
0.12
0.10
0.08
0.06
0.04
0.02
–0.02
–0.04
0
ρb – ρlog
(g/cm3)
φ = 40%
φ = 0
φ = 40%
Limes tone
A n t h r a c i t e C o a l B i t u m
i n o u s
Gypsum
Limestone + water
Dolomite + wa ter
Neutron—Wireline
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Neu
Dual-Spacing Compensated Neutron Tool Charts
This section contains interpretation charts to cover developments in
compensated neutron tool (CNT) porosity transforms, environmentalcorrections, and porosity and lithology determination.
CSU* software (versions CP-30 and later) and MAXIS* software
compute three thermal porosities: NPHI, TNPH, and NPOR.
NPHI is the “classic NPHI,” computed from instantaneous near
and far count rates, using “Mod-8” ratio-to-porosity transform with
a caliper correction.
TNPH is computed from deadtime-corrected, depth- and
resolution-matched count rates, using an improved ratio-to-porosity
transform and performing a complete set of environmental correctionsin real time. These corrections may be turned on or off by the field
engineer at the wellsite. For more information see Reference 32.
NPOR is computed from the near-detector count rate and TNPH
to give an enhanced resolution porosity. The accuracy of NPOR is
equivalent to the accuracy of TNPH if the environmental effects on
the near detector change less rapidly than the formation porosity.
For more information on enhanced resolution processing, see
Reference 35.
Cased hole CNT logs are recorded on NPHI, computed frominstantaneous near and far count rates, with a cased hole ratio-to-
porosity transform.
Using the Neutron Correction Charts
For logs labeled NPHI:1. Enter Chart Neu-5 with NPHI and caliper reading to convert to
uncorrected neutron porosity.
2. Enter Charts Neu-1 and Neu-3 to obtain corrections for each
environmental effect. Corrections are summed with the uncor-
rected porosity to give a corrected value.
3. Use crossplot Charts Por-11 and Por-12 for porosity and lithology
determination.
For logs labeled TNPH or NPOR, the CSU wellsite surface instru-mentation and MAXIS software have applied environmental correc-
tions as indicated on the log heading. If the CSU and MAXIS
software has applied all corrections, TNPH or NPOR can be used
directly with the crossplot charts. In this case:
1. Use crossplot Charts Por-11 and Por-12 to determine porosity
and lithology.
Neutron—Wireline
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Neu
Compensated Neutron ToolEnvironmental Correction—Open Hole
Purpose
Chart Neu-1 is used to correct the compensated neutron log porosity index if the caliper correction was not applied. If the caliper correc-
tion is applied, it must be “backed out” to use this chart.
DescriptionThis chart is used only if the caliper correction was not applied
to the logged data. The parameter section of the log heading lists
whether correction was applied.
Example 1: Backed-Out Correction of TNPH Porosity
Given: Thermal neutron porosity (TNPH) from the log = 32 p.u.
(apparent limestone units) and borehole size = 12 in.
Find: Uncorrected TNPH with the correction backed out.
Answer: Enter the top chart for actual borehole size at the inter-
section point of the standard conditions 8-in. horizontal
line and 32 p.u. on the scale above the chart.
From this point, follow the closest trend line to intersect
the 12-in. line for the borehole size.
The intersection is the uncorrected TNPH value of 34 p.u.
To use the uncorrected value on Chart Neu-1, draw a ver-
tical line from this intersection through the remainder of
the charts, as shown by the red line.
Example 2: Environmentally Corrected THPH
Given: Neutron porosity of 32 p.u. (apparent limestone units), without environmental correction, 12-in. borehole, 1 ⁄ 4-in.
thick mudcake, 100,000-ppm borehole salinity, 11-lbm/gal
natural mud weight (water-base mud [WBM]), 150°F
borehole temperature, 5,000-psi pressure (WBM), and
100,000-ppm formation salinity.
Find: Environmentally corrected TNPH porosity.
Answer: If there is standoff (which is not uncommon), use Chart
Neu-3. Then use Chart Neu-1 by drawing a vertical linethrough the charts for the previously determined
backed-out (uncorrected) 34-p.u. neutron porosity
value.
On each environmental correction chart, enter the y-axis
at the given value and move horizontally left to intersect
the porosity value vertical line.
For example, on the mudcake thickness chart the line
extends from 1 ⁄ 4 in. on the y-axis.
At the intersection point, move parallel to the closest
blue trend line to intersect the standard conditions, as
indicated by the bullet.
The point of intersection with the standard conditions
for the chart is the value of porosity corrected for the
particular environment. The change in porosity value
(either positive or negative) is summed for the charts
and referred to as delta porosity (∆φ).
The ∆φ net correction applied to the uncorrected log neutronporosity is listed in the table for the two examples.
Neutron—Wireline
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Compensated Neutron ToolEnvironmental Correction—Open Hole
Neu-1(customary, former Por-14c)
0 10 20 30 40 50
Actual borehole size(in.)
1.0
0.5
0
Mudcake thickness(in.)
250
0
Borehole salinity(1,000 × ppm)
Mud weight(lbm/gal)
Natural
300
B h l t t
18161412
108
Barite
Neutron log porosity index (apparent limestone porosity in p.u.)
2420161284
•
•
•
•
•
1312111098
Neu
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Neu
Compensated Neutron ToolEnvironmental Correction—Open Hole
Neu-2(metric, former Por-14cm)
0 10 20 30 40 50
600500400300200100
Actual borehole size(mm)
25
12.5
0
Mudcake thickness(mm)
250
0
Borehole salinity(g/kg)
149121
1.5
1.0Mud density(g/cm3)
N a t u r a l
2.0
1.0 B
a r i t e
Neutron log porosity index (apparent limestone porosity)
•
•
•
•
•
Neutron—Wireline
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Neu
Purpose
Chart Neu-3 is used to determine the porosity change caused by standoff to the uncorrected thermal neutron porosity TNPH from
Chart Neu-1.
DescriptionEnter the appropriate borehole size chart at the estimated neutron
tool standoff on the y-axis. Move horizontally to intersect the uncor-
rected porosity. At the intersection point, move along the closest
trend line to the standard conditions line defined by the bullet to
the right of the chart. This point is the porosity value corrected fortool standoff. The difference between the standoff-corrected porosity
and the uncorrected porosity is the correction itself.
Example
Given: TNPH = 34 p.u., borehole size = 12 in., andstandoff = 0.5 in.
Find: Porosity corrected for standoff.
Answer: Draw a vertical line from the uncorrected neutron log
porosity of 34 p.u. Enter the 12-in. borehole chart at
0.5-in. standoff and move horizontally right to intersect
the vertical porosity line. From the point of intersection
move parallel to the closest trend line to intersect the
standard conditions line (standoff = 0 in.). The standoff-corrected porosity is 32 p.u. The correction is –2 p.u.
Compensated Neutron ToolStandoff Correction—Open Hole
Neutron—Wireline
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Neu
Compensated Neutron ToolStandoff Correction—Open Hole
Neu-3(customary, former Por-14d)
0 10 20 30 40 50
7
6
5
4
3
2
1
4
3
2
1
0
3
2
1
0
2
1
0
1
0
Actualborehole size
6 in.
8 in.
10 in.
12 in.
18 in.
Standoff(in.)
Neutron log porosity index (apparent limestone porosity in p.u.)
•
•
•
•
Neutron—Wireline
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Neu
Compensated Neutron ToolStandoff Correction—Open Hole
Neu-4(metric, former Por-14dm)
0 10 20 30 40 50
175
150
125
100
75
50
25
100
75
50
25
0
75
50
25
0
50
25
0
25
0
Actualborehole size
150 mm
200 mm
250 mm
300 mm
450 mm
Standoff(mm)
Neutron log porosity index (apparent limestone porosity)
•
•
•
•
Neutron—Wireline
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Neu
Compensated Neutron ToolConversion of NPHI to TNPH—Open Hole
Neu-5(former Por-14e)
Purpose
This chart is used to determine the porosity change caused by the
borehole size to the neutron porosity NPHI and convert the porosity
to thermal neutron porosity (TNPH). This chart corrects NPHI only
for the borehole sizes that differ from the standard condition of 8 in.
Refer to Chart Neu-1 to complete the environmental corrections for
the TPNH value obtained.
Description
Enter the scale at the top of the chart with the NPHI porosity.
Example
At the point of intersection of the vertical line and the
standard conditions line, move parallel to the closest
trend line to intersect the actual borehole size line.
At that intersection point move vertically down to the
bottom scale to determine the TNPH porosity corrected
only for borehole size. This value is also used to deter-
mine the change in porosity as a result of tool standoff.
TNPH = 12.5 + 5 = 17.5 p.u.
TNPH porosity index (apparent limestone porosity in p.u.)
242016128
4
Borehole size(in.)
–5 0 10 20 30 40 50
0 10 20 30 40 50
NPHI porosity index (apparent limestone porosity in p.u.)
•
• Standard conditions
© Schlumberger
Neutron—Wireline
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Neu
Compensated Neutron ToolFormation Σ Correction for Environmentally Corrected TNPH—Open Hole
Purpose
This chart is used to further correct the environmentally correctedTNPH porosity from Chart Neu-1 for the effect of the total forma-
tion capture cross section, or sigma (Σ), of the formation of inter-
est. This correction is applied after all environmental corrections
determined with Chart Neu-1 have been applied.
DescriptionEnter the chart with Σ for the appropriate formation along the y-axis
and the corrected TNPH porosity along the x-axis. Where the lines
drawn from these points intersect, move parallel to the closest trendline to intersect the appropriate fresh- or saltwater line to read the
corrected porosity.
The chart at the bottom of the page is used to correct the Σ-
corrected porosity for salt displacement if the formation Σ is due to
salinity. However, this correction is not made if the borehole salinity
correction from Chart Neu-1 has been applied.
Example
Given: Corrected TNPH from Chart Neu-1 = 38 p.u., Σ of thesandstone formation = 33 c.u., and formation salinity =
150,000 ppm (indicating a freshwater formation).
Find: TNPH porosity corrected with Chart Neu-1 and for Σ of
the formation.
Answer: Enter the appropriate chart with the Σ value on the y-axis
and the corrected TNPH value on the x-axis. At the inter-
section of the sigma and porosity lines, parallel the clos-
est trend line to intersect the freshwater line. (If the water in the formation is salty, the 250,000-ppm line
should be used.)
Move straight down from the intersection point to the
formation salinity chart at the bottom.
From the point where the straight line intersects the top
of the salinity correction chart, parallel the closest trend
line to intersect the formation salinity line.
Draw a vertical line to the bottom scale to read the cor-
rected formation sigma TNPH porosity, which is 35 p.u.
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Neu
0 10 20 30 40 50
70
60
70
60
50
40
30
20
10
0
Neutron log porosity index
Sandstone formation
Formation Σ (c.u.)
Fresh water
250,000-ppm water
Limestone formationFormation Σ (c.u.)
Fresh water
250,000-ppm water
70
60
5040
30
20
10
0
Compensated Neutron ToolFormation Σ Correction for Environmentally Corrected TNPH—Open Hole
Neu-6(former Por-16)
Neutron—Wireline
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Neu
Compensated Neutron ToolMineral Σ Correction for Environmentally Corrected TNPH—Open Hole
Purpose
This chart is used to further correct the environmentally correctedTNPH porosity from Chart Neu-1 for the effect of the mineral sigma
(Σ). This correction is applied after all environmental corrections
determined with Chart Neu-1 have been applied.
Description
Enter the chart for the formation type with the mineral Σ value along
the y-axis and the Chart Neu-1 corrected TNPH porosity along the
x-axis. Where lines drawn from these points intersect, move parallel to
the closest trend line to intersect the freshwater line to read thecorrected porosity on the scale at the bottom. The choice of chart
depends on the type of mineral in the formation.
Example
Given: Corrected TNPH from Chart Neu-1 = 38 p.u., sandstoneformation Σ = 35 c.u., and formation salinity =
150,000 ppm (indicating a freshwater formation).
Find: TNPH porosity corrected with Chart Neu-1 and for the
mineral Σ.
Answer: At the intersection of theΣ and porosity value lines
move parallel to the closest trend line to intersect the
freshwater line. Move straight down to intersect the bot-
tom prosity scale to read the TNPH porosity correctedfor mineral Σ, which is 33 p.u.
Neutron—Wireline
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Neu
Compensated Neutron ToolMineral Σ Correction for Environmentally Corrected TNPH—Open Hole
0 10 20 30 40 50
Neutron log porosity index
Sandstone formationMineral Σ (c.u.)
Fresh water
Fresh water
70
60
50
40
30
20
10
0
Limestone formationMineral Σ (c.u.)
70
60
50
40
30
20
10
0
Neu-7(former Por-17)
General
Neutron—Wireline
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Neu
Compensated Neutron ToolFluid Σ Correction for Environmentally Corrected TNPH—Open Hole
Purpose
This chart is used to correct the environmentally corrected TNPHporosity from Chart Neu-1 for the effect of the fluid sigma (Σ) in
the formation. This correction is applied after all environmental
corrections determined with Chart Neu-1 have been applied.
Description
Enter the appropriate formation chart with the formation fluid Σ
value on the y-axis and the Chart Neu-1 corrected TNPH porosity on
the x-axis. Where the lines drawn from these points intersect, move
parallel to the closest trend line to intersect the appropriate fresh-or saltwater line. If the borehole salinity correction from Chart Neu-1
has not been applied, from this point extend a line down to intersect
the formation salinity chart at the bottom. Move parallel to the
closest trend line to intersect the formation salinity line. Move
straight down to read the corrected porosity on the scale below
the chart.
Example
Given: Corrected TNPH from Chart Neu-1 = 30 p.u. (withoutborehole salinity correction), fluid Σ = 80 c.u., fluid
salinity = 150,000 ppm, and sandstone formation.
Find: TNPH corrected with Chart Neu-1 and for fluid Σ.
Answer: At the intersection of the fluid Σ and Chart Neu-1
corrected TNPH porosity (30-p.u.) line, move parallel
to the closest trend line to intersect the freshwater line.
From that point go straight down to the formation salinity
correction chart at the bottom.Move parallel to the closest trend line to intersect the
formation salinity line (150,000 ppm), and then draw a
vertical line to the bottom scale to read the corrected
TNPH value (26 p.u.).
Neutron—Wireline
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Neu
0 10 20 30 40 50
Neutron log porosity index
Sandstone formationFluid Σ (c.u.)
Limestone formationFluidΣ (c.u.)
160
140
120
100
80
60
40
20
160
140
120
100
80
60
40
20
160
Fresh water
250,000-ppm water
Fresh water
250,000-ppm water
Compensated Neutron ToolFluid Σ Correction for Environmentally Corrected TNPH—Open Hole
Neu-8(former Por-18)
Neutron—Wireline
C d N T l
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Neu
Compensated Neutron ToolEnvironmental Correction—Cased Hole
Purpose
This chart is used to obtain the correct porosity from the neutronporosity index logged with the compensated neutron tool in casing,
where the effects of the borehole size, casing thickness, and cement
sheath thickness influence the true value of formation porosity.
Description
Enter the scale at the top of the chart with a whole-number (not
fractional) porosity value. Draw a straight line vertically through
the three charts representing borehole size, casing thickness, and
cement thickness. Draw a horizontal line on each chart from theappropriate value on the y-axis. At the intersection point of the verti-
cal line and the horizontal line on each chart proceed to the blue
dashed horizontal line by following the slope of the blue solid lines
on each chart. At that point read the change in porosity index. The
cumulative change in porosity is added to the logged porosity to obtain
the corrected value. As can be seen, the major influences to the casing-
derived porosity are the borehole size and the cement thickness. The
same procedure applies to the metric chart.
The blue dashed lines represent the standard conditions from which the charts were developed: 83 ⁄ 4-in. open hole, 51 ⁄ 2-in. 17-lbm
casing, and 1.62-in. annular cement thickness.
The neutron porosity equivalence nomographs at the bottom are
used to convert from the log standard of limestone porosity to poros-
ity for other matrix materials.
The porosity value corrected with Chart Neu-9 is entered into
Chart Neu-1 to provide environmental corrections necessary for
determining the correct cased hole porosity value.
Example
Given: Log porosity index = 27%, borehole diameter = 11 in.,casing thickness = 0.304 in., and cement thickness =
1.62 in.
Cement thickness is defined as the annular space
between the outside wall of the casing and the borehole
wall. The value is determined by subtracting the casing
outside diameter from the borehole diameter and divid-
ing by 2.
Find: Porosity corrected for borehole size, casing thickness,and cement thickness.
Answer: Draw a vertical line (shown in red) though the three
charts at 27 p.u.
Borehole-diameter correction chart: From the intersec-
tion of the vertical line and the 11-in. borehole-diameter
line (shown in red dashes) move upward along the
curved blue line as shown on the chart.
The porosity is reduced to 26% by –1 p.u.
Casing thickness chart: The porosity index is changed
by 0.3 p.u.
Cement thickness chart: The porosity index is changed
by 0.5 p.u.
The resulting corrected porosity for borehole, casing,
and cement is 27 – 1 + 0.3 + 0.5 = 26.8 p.u.
Neutron—Wireline
C d N T l
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Neu
Compensated Neutron ToolEnvironmental Correction—Cased Hole
0 10 20 30 40 50
468
10121416
0.2
0.3
0.4
0.5
0
1
2
3
+0.3
+0.5
Borehole, casing, and cement correction = –1.0 + 0.3 + 0.5
–1.0
1.62 in.
0.304 in.
83 ⁄ 4 in.
Neutron log porosity index(p.u.)
Diameter of boreholebefore running casing
(in.)
Cement thickness(in.)
Casing thickness (in.)9.5
11.613.515.1
14
17
20
23
20
26
32
29
40
47
41 ⁄ 2 51 ⁄ 2 7 95 ⁄ 8
OD (in.)
Casingweight(lbm/ft)
Customary
•
•
•
0 10 20 30 40 50
100
200
300222 mm
Neutron log porosity index(p.u.)
Diameter of boreholebefore running casing
(mm)
Metric
•
Neu-9(former Por-14a)
Neutron—Wireline
APS* A l t P it S d
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Neu
APS* Accelerator Porosity SondeEnvironmental Correction—Open Hole
Purpose
The Neu-10 charts pair is used to correct the APS Accelerator Porosity Sonde apparent limestone porosity for mud weight and actual bore-
hole size. The charts are for the near-to-array and near-to-far poros-
ity measurements. The design of the APS sonde resulted in a
significant reduction in environmental correction. The answer deter-
mined with this chart is used in conjunction with the correction
from Chart Neu-11.
Description
Enter the appropriate chart pair (mud weight and actual boreholesize) for the APS near-to-array apparent limestone porosity (APLU)
or APS near-to-far apparent limestone porosity (FPLU) with the
uncorrected porosity from the APS log by drawing a straight vertical
line (shown in red) through both of the charts. At the intersection
with the mud weight value, move parallel to the closest trend line to
intersect the standard conditions line. This point represents a change
in porosity resulting from the correction for mud weight. Follow the
same procedure for the borehole size chart to determine that correc-
tion change. Because the borehole size correction has a dependency on mud weight, even with natural muds, there are two sets of curves
on the borehole size chart—solid for light muds (8.345 lbm/gal) and
dashed for heavy muds (16 lbm/gal). Intermediate mud weights are
interpolated. The two differences are summed for the total correc-
tion to the APS log value.
This answer is used in Chart Neu-11 to complete the environ-
mental corrections for corrected APLU or FPLU porosity.
Example
Given: APS neutron APLU uncorrected porosity = 34 p.u.,mud weight = 10 lbm/gal, and borehole size = 12 in.
Find: Corrected APLU porosity.
Answer: Draw a vertical line on the APLU mud weight chart from
34 p.u. on the scale above. At the intersection with the
10-lbm/gal mud weight line, move parallel to the trend
line to intersect the standard conditions line. This point
represents a change in porosity of –0.75 p.u.
On the actual borehole size chart, move parallel to theclosest trend line from the intersection of the 34-p.u.
line and the actual borehole size (12 in.) to intersect
the 8-in. standard conditions line. This point represents
a change in porosity of –1.0 p.u.
The total correction is –0.75 + –1.0 = –1.75 p.u.,
which results in a corrected APLU porosity of
34 – 1.75 = 32.25 p.u.
Neutron—Wireline
APS* A l t P it S d
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Neu
APS near-to-far apparent limestone porosity uncorrected, FPLU (p.u.)
Mud weight(lbm/gal)
Actualborehole size
(in.)
18
16
14
12
10
8
16
14
12
10
8
2.01.81.61.41.21.0
400
350
300
250
200
(g/cm3)
(mm)
•
•
APS near-to-array apparent limestone porosity uncorrected, APLU (p.u.)
0 10 20 30 40 50
Mud weight(lbm/gal)
Actualborehole size
(in.)
18
16
1412
10
8
16
14
12
10
8
6
2.01.8
1.61.41.21.0
400
350
300
250
200
(g/cm3)
(mm)
•
•
APS* Accelerator Porosity SondeEnvironmental Correction—Open Hole
Neu-10(former Por-23a)
Neutron—Wireline
APS* A l t P it S d With t E i t l C ti
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Neu
Purpose
This chart is used to complete the environmental correction for APLU and FPLU porosities from the APS log.
Description
Example
Given: APLU or FPLU porosity = 34 p.u., formation tempera-ture = 150°F, formation pressure = 5,000 psi, and for-
mation salinity = 150,000 ppm.
50 100 150 200 250 300 35010 38 66 93 121 149 177
50 150 250
Formation salinity(ppt or g/kg)
Formation porosity(p.u.)
50 30 10 0
Formation temperature
(°F)(°C)
12
11
10
9
8
7
6
5
4
3
2
1
0
–1
Apparentporositycorrection
(p.u.)
(psi) (MPa)
0 0
2,500
5,000 34
7,500
10,000 69
12,500
15,000 103
17,500 20,000 138
Pressure
APS* Accelerator Porosity Sonde Without Environmental CorrectionsEnvironmental Correction—Open Hole
Neu-11(former Por-23b)
*Mark of Schlumberger© Schlumberger
Neutron—LWD
CDN* Compensated Density Neutron adnVISION* Azimuthal Density
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Neu
Purpose
This chart is used to determine one of several environmentalcorrections for neutron porosity values recorded with the CDN
Compensated Density Neutron, adnVISION Azimuthal Density
Neutron, and EcoScope Integrated LWD tools. The value of hydrogen
index (Hm) is used in the following porosity correction charts.
Description
To determine the Hm of the drilling mud, the mud weight, tempera-
ture, and hydrostatic mud pressure at the zone of interest must
be known.
Example
Given: Barite mud weight = 14 lbm/gal, mud temperature = 150°F,and hydrostatic mud pressure = 5,000 psi.
Find: Hydrogen index of the drilling mud.
Answer: Enter the bottom chart for mud weight at 14 lbm/gal on
the y-axis. Move horizontally to intersect the barite line.
Move vertically to the bottom of the mud temperature
chart and move upward parallel to the closest trend line
to intersect the formation temperature. From the inter-
section point move vertically to the bottom of the mudpressure chart.
Move parallel to the closest trend line to intersect the
formation pressure. Draw a line vertically to intersect
the mud hydrogen index scale and read the result.
Mud hydrogen index = 0.78.
CDN* Compensated Density Neutron, adnVISION* Azimuthal DensityNeutron, and EcoScope* Integrated LWD ToolsMud Hydrogen Index Determination
Neutron—LWD
CDN* Compensated Density Neutron adnVISION* Azimuthal Density
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Neu
CDN* Compensated Density Neutron, adnVISION* Azimuthal DensityNeutron, and EcoScope* Integrated LWD ToolsMud Hydrogen Index Determination
Neu-30(former Por-19)
0.70 0.75 0.80 0.85 0.90 0.95 1
25
20
10
0
Mudpressure
(1,000 × psi)
300
200
100
50
Mud temperature
(°F)
Mud hydrogen index, Hm
Neutron—LWD
adnVISION475* Azimuthal Density Neutron 4 75 in Tool and 6 in Borehole
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Neu
Purpose
This is one of a series of charts used to correct adnVISION4754.75-in. Azimuthal Density Neutron tool porosity for several environ-
mental effects by using the mud hydrogen index (Hm) determined
from Chart Neu-30 in conjunction with the parameters on the chart.
DescriptionThis chart incorporates the parameters of borehole size, mud tem-
perature, mud hydrogen index (from Chart Neu-30), mud salinity,
and formation salinity for the correction of adnVISION475 porosity.
The following charts are used with the same interpretationprocedure as Chart Neu-31. The charts differ for tool size and
borehole size.
Example
Given: adnVISION475 uncorrected porosity = 34 p.u., boreholesize = 10 in., mud temperature = 150°F, hydrogen
index = 0.78, borehole salinity = 100,000 ppm, and forma-
tion salinity = 100,000 ppm.
Find: Corrected adnVISION475 porosity.
Answer: From the adnVISION475 porosity of 34 p.u. on the top
scale, enter the borehole size chart to intersect the bore-
hole size of 10 in. From the point of intersection move
parallel to the closest trend line to intersect the stan-
dard conditions line.
From this intersection point move straight down to
enter the mud temperature chart and intersect the mud
temperature of 150°F. From the point of intersection
move parallel to the closest trend line to intersect the
standard conditions line.
Continue this pattern through the charts to read the
corrected porosity from the scale at the bottom of the
charts.The corrected adnVISION475 porosity is 17 p.u.
adnVISION475* Azimuthal Density Neutron—4.75-in. Tool and 6-in. BoreholeEnvironmental Correction—Open Hole
Neutron—LWD
adnVISION475* Azimuthal Density Neutron 4 75 in Tool and 6 in Borehole
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Neu
adnVISION475 Azimuthal Density Neutron—4.75-in. Tool and 6-in. BoreholeEnvironmental Correction—Open Hole
Neu-31
Boreholesize(in.)
0 10 20 30 40 50
Mudhydrogenindex, Hm
Mudsalinity
(1,000 × ppm)
Mud temperature
(°F)
•
•
•
•
6
8
10
100
0.7
0.8
0.9
1.0
200
300
0
100
200
adnVISION475 neutron porosity index (apparent limestone porosity) in 6-in. borehole
200
Neutron—LWD
adnVISION475* BIP Neutron 4 75 in Tool and 6 in Borehole
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Neu
adnVISION475 BIP Neutron—4.75-in. Tool and 6-in. BoreholeEnvironmental Correction—Open Hole
Neu-32
0 10 20 30 40 50
Mudhydrogenindex, Hm
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
Mud temperature
(°F)
adnVISION475 neutron porosity index (apparent limestone porosity) in 6-in. borehole
100
0.7
0.8
0.9
1.0
200
300
100
200
0
100
200
Neutron—LWD
adnVISION475* Azimuthal Density Neutron—4 75-in Tool
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Neu
adnVISION475 Azimuthal Density Neutron—4.75-in. Tooland 8-in. BoreholeEnvironmental Correction—Open Hole
Neu-33
Boreholesize(in.)
0 10 20 30 40 50
Mudhydrogenindex, Hm
Mudsalinity
(1,000 × ppm)
Mud temperature
(°F)
•
•
•
•
6
8
10
100
0.7
0.8
0.9
1.0
200
300
0
100
200
adnVISION475 neutron porosity index (apparent limestone porosity) in 8-in. borehole
200
Neutron—LWD
adnVISION475* BIP Neutron—4 75-in Tool and 8-in Borehole
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Neu
adnVISION475 BIP Neutron 4.75-in. Tool and 8-in. BoreholeEnvironmental Correction—Open Hole
Neu-34
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 0 20 30 0 0
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
Mud temperature
(°F)
adnVISION475 neutron porosity index (apparent limestone porosity) in 8-in. borehole
100
0.7
0.8
0.9
1.0
200
300
100
200
0
0
100
200
Neutron—LWD
adnVISION675* Azimuthal Density Neutron—6 75-in Tool and 8-in Borehole
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Neu
250
200
300
200
100
50
Mud temperature
(°F)
•
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
•
adnVISION675 neutron porosity index (apparent limestone porosity in p.u.)
0 10 20 30 40 50
16
14
12
10
8
Boreholesize(in.)
•
adnVISION675 Azimuthal Density Neutron 6.75 in. Tool and 8 in. BoreholeEnvironmental Correction—Open Hole
Neu-35(former Por-26a)
adnVISION675* BIP Neutron—6 75-in Tool and 8-in Borehole
Neutron—LWD
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adnVISION675 BIP Neutron 6.75 in. Tool and 8 in. BoreholeEnvironmental Correction—Open Hole
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 10 20 30 40 50
Mudsalinity(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
Mud temperature
(°F)
adnVISION475 neutron porosity index (apparent limestone porosity) in 8-in. borehole
100
0.7
0.8
0.9
1.0
200
300
100
200
0
0
100
200
Neu
Neu-36
Neutron—LWD
adnVISION675* Azimuthal Density Neutron—6 75-in Tool and 10-in Borehole
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Neu
adnVISION675 Azimuthal Density Neutron 6.75 in. Tool and 10 in. BoreholeEnvironmental Correction—Open Hole
Neu-37(former Por-26b)
250
200
300
200
100
50
Mud temperature
(°F)
•
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
•
adnVISION675 neutron porosity index (apparent limestone porosity in p.u.)
0 10 20 30 40 50
16
14
12
10
8
Boreholesize(in.)
•
Neutron—LWD
adnVISION675* BIP Neutron—6.75-in. Tool and 10-in. Borehole
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Neu
adnVISION675 BIP Neutron 6.75 in. Tool and 10 in. BoreholeEnvironmental Correction—Open Hole
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 10 20 30 40 50
Mudsalinity(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
Mud temperature
(°F)
adnVISION675 neutron porosity index (apparent limestone porosity) in 10-in. borehole
100
0.7
0.8
0.9
1.0
200
300
100
200
0
0
100
200
Neu-38
Neutron—LWD
adnVISION825* Azimuthal Density Neutron—8.25-in. Tool
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Neu
adnVISION825 Azimuthal Density Neutron 8.25 in. Tooland 12.25-in. BoreholeEnvironmental Correction—Open Hole
Neu-39
Standoff(in.)
0 10 20 30 40 50
Mud temperature
(°F)
Mudhydrogenindex, Hm
Pressure
Boreholesize(°F)
1.5
0.5
0
1.0
12
10
300
200
100
14
16
1
0.7
0.8
0.9
adnVISION825 neutron porosity index (apparent limestone porosity) in 12.25-in. borehole
Standoff = 0.25 in.
10
20
•
•
•
•
Neutron—LWD
CDN* Compensated Density Neutron and adnVISION825s*
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Neu
p s s y sAzimuthal Density Neutron—8-in. Tool and 12-in. BoreholeEnvironmental Correction—Open Hole
Neu-40(former Por-24c)
18
16
14
12
Boreholesize(in.)
Neutron porosity index (apparent limestone porosity) in 12-in. borehole
0 10 20 30 40 50
Mud
•
•
•
250
200
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
350
300
200
100
50
Mud temperature
(°F)
Neutron—LWD
CDN* Compensated Density Neutron and adnVISION825s*
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Neu
p yAzimuthal Density Neutron—8-in. Tool and 14-in. BoreholeEnvironmental Correction—Open Hole
Neu-41(former Por-24d)
350
300
200
100
50
Mud temperature
(°F)
18
16
14
12
Boreholesize(in.)
Neutron porosity index (apparent limestone porosity) in 14-in. borehole 0 10 20 30 40 50
•
•
•
A
B
C
0.7
0.8
0.9
1 0
Mudhydrogenindex, H
m
D
E
F
Neutron—LWD
CDN* Compensated Density Neutron and adnVISION825s*N 42
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Neu
p yAzimuthal Density Neutron—8-in. Tool and 16-in. BoreholeEnvironmental Correction—Open Hole
18
16
14
12
Boreholesize(in.)
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
Neutron porosity index (apparent limestone porosity) in 16-in. borehole
0 10 20 30 40 50
•
•
•
350
300
200
100
50
Mud temperature
(°F)
Neu-42(former Por-24e)
Neutron—LWD
EcoScope* Integrated LWD Neutron Porosity—6.75-in. Tool
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Purpose
Charts Neu-43 through Neu-46 show the environmental correctionsthat are applied to EcoScope 6.75-in. Integrated LWD Tool neutron
porosity measurements. These charts can be used to estimate the
correction that is normally already applied to the field logs.
Description
The charts incorporate the parameters of borehole size, mud tem-
perature, mud hydrogen index (from Chart Neu-30), mud salinity,
and formation salinity for the correction of EcoScope 6.75-in.
neutron porosity.
Select the appropriate chart based on both the hole size and
the measurement type: thermal neutron porosity (TNPH) or best
thermal neutron porosity (BPHI).
Enter the charts with the uncorrected neutron porosity data.
Charts Neu-43 and Neu-44 are for use with BPHI_UNC, and ChartsNeu-45 and Neu-46 are for use with TNPH_UNC. Because the bore-
hole size correction is applied to the field logs, including the _UNC
channels, do not include the borehole size correction, which is in the
charts for illustrative purposes only.
A correction for eccentricity effects is normally also applied to
the field BPHI measurement. Because this correction is not included
in these charts, there may be a small difference between the correc-
tion estimated from the charts and that actually applied to the field
data, depending on the tool position in the borehole.The charts are used with a similar procedure to that described
for Chart Neu-31.
p g yEnvironmental Correction—Open Hole
Neu
Neutron—LWD
EcoScope* Integrated LWD BPHI Porosity—6.75-in. Tool and 8.5-in. BoreholeN 43
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p g yEnvironmental Correction—Open Hole
Neu-43
14
13
12
11
10
9
8
Boreholesize(in.)
0.70
0.75
0.80
0.85
0.90
0.95
1.00
Mudhydrogenindex, Hm
EcoScope uncorrec ted BPHI porosity (apparent limestone porosity in p.u.) in 8.5-in. borehole
0 10 20 30 40 50
Mud
•
•
• 250
200
150
260
210
160
110
60
Temperature(°F)
Neu
Neutron—LWD
EcoScope* Integrated LWD BPHI Porosity—6.75-in. Tool and 9.5-in. BoreholeNeu 44
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Environmental Correction—Open Hole Neu-44
14
13
12
11
10
9
8
Boreholesize(in.)
0.70
0.75
0.80
0.85
0.90
0.95
1.00
Mudhydrogenindex, Hm
EcoScope uncorrec ted BPHI porosity (apparent limestone porosity in p.u.) in 9.5-in. borehole
0 10 20 30 40 50
Mud
•
•
• 250
200
150
260
210
160
110
60
Temperature(°F)
Neu
Neutron—LWD
EcoScope* Integrated LWD TNPH Porosity—6.75-in. Tool and 8.5-in. BoreholeNeu 45
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Environmental Correction—Open Hole Neu-45
14
13
12
11
10
9
8
Boreholesize(in.)
0.70
0.75
0.80
0.85
0.90
0.95
1.00
Mudhydrogenindex, Hm
EcoScope uncorrec ted TNPH porosity (apparent limestone porosity in p.u.) in 8.5-in. borehole
0 10 20 30 40 50
Mud
•
•
• 250
200
150
260
210
160
110
60
Temperature(°F)
Neu
Neutron—LWD
EcoScope* Integrated LWD TNPH Porosity—6.75-in. Tool and 9.5-in. BoreholeNeu 46
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Environmental Correction—Open Hole Neu-46
14
13
12
11
10
9
8
Boreholesize(in.)
0.70
0.75
0.80
0.85
0.90
0.95
1.00
Mudhydrogenindex, Hm
EcoScope uncorrec ted TNPH porosity (apparent limestone porosity in p.u.) in 9.5-in. borehole
0 10 20 30 40 50
Mud
•
•
• 250
200
150
260
210
160
110
60
Temperature(°F)
Neu
Neutron—LWD
EcoScope* Integrated LWD—6.75-in. Tool
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Formation Sigma Environmental Correction—Open Hole
Purpose
This chart is used to environmentally correct the raw sigma (RFSA)measurement for porosity, borehole size, and mud salinity. The fully
corrected sigma (SIFA) measurement is normally presented on the
logs.
Description
Chart Neu-47 includes (from top to bottom) the moments sigma
transform, diffusion correction based on porosity, and borehole
correction.
ExampleGiven: Raw sigma (24 c.u.), porosity (30 p.u.), borehole size
(10 in.), and mud salinity (200,000 ppm).
Find: Corrected sigma (SIFA).
Answer: Enter the chart from the scale at the top with the raw
sigma value of 24 c.u.
Moments Sigma Transform
Move parallel to the closest trend line to intersect the x-axis of the
moments sigma transform chart. The difference between the x-axis value and the raw sigma value is the moments sigma transform
correction (19.8 – 24 = –4.2 c.u.).
Diffusion Correction
Move down vertically from the scale at the top to intersect the30-p.u. line on the porosity chart. At the intersection point, move
parallel to the closest trend line to intersect the x-axis of the
porosity chart.
The difference between the x-axis value and the raw sigma value
is the diffusion correction (25.3 – 24 = +1.3 c.u.).
Borehole Correction
Move down vertically from the scale at the top to intersect the 10-in.
borehole size line. At the intersection point, move parallel to theclosest trend line corresponding to the mud salinity to intersect
the x-axis of the borehole correction chart.
The difference between the x-axis value and the raw sigma value
is the borehole correction (22.8 – 24 = –1.2 c.u.).
Net Correction
The net correction to apply to the raw sigma value is the sum the
three corrections (–4.2 + 1.3 + –1.2 = –4.1 c.u.). The environmentally
corrected sigma is the sum of the net correction and the raw sigma value (24 + –4.1 = 19.9 c.u.).
Neu
EcoScope Sigma Correction Example
Correction
Raw sigma 24 c.u.
Porosity 30 p.u.Borehole size 10 in.
Mud salinity 200,000 ppm
Neutron—LWD
EcoScope* Integrated LWD—6.75-in. ToolNeu-47
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Formation Sigma Environmental Correction—Open Hole Neu-47
11
10
9
50
40
30
20
10
0
0 10 20 30 40 50 60
Mud salinity 0 ppm
50 000 ppm
Raw sigma (c
.u.)
Momentssigma
transform
Porosity(p.u.)
Borehole
size (in.)
Neu
General
Nuclear Magnetic Resonance–—Wireline
CMR* ToolCMR-1
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NMR
Hydrocarbon Effect on NMR/Density Porosity Ratio CMR 1
1.0
1.0
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.8
0.4
0.4
0.2
0.2
0
0
0.6
0.61 – Sxo
1.4
1.6
1.8
2 0Gas Gas
30 p u 30 p u
40 p.u. 40 p.u.
0%
20%40%
60%80%
0%
20%40%
60%80%
Porosity = 50 p.u. Porosi ty = 50 p.u.
1.4
1.6
1.8
2 0
ρma = 2.65, ρf = 1, If = 1, ρgas = 0.25,PT = 4, T1 gas = 4, IH = 0.5
Fresh Mud and Dry Gas at 700 psi Fresh Mud and Dry Gas at 700 psi
ρma = 2.71, ρf = 1, If = 1, ρgas = 0.25,PT = 4, T1 gas = 4, Igas = 0.5
φ tCMR
φD
ρh = 0.8
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Resistivity Laterolog—Wireline
ARI* Azimuthal Resistivity ImagerE i l C i O H l
RLl-1
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Environmental Correction—Open Hole RLl 1
(former Rcor-14)
PurposeThis chart is used to environmentally correct the ARI Azimuthal
Resistivity Imager high-resolution resistivity (LLhr) curve for theeffect of borehole size.
Description
ExampleGiven: ARI LLhr resistivity (Ra ) = 20 ohm-m, mud resistivity
(Rm) = 0.02 ohm-m, and borehole size at the zone of interest = 10 in.
Find: True resistivity (Rt).
1 10 100 1,000 10,000
1.5
1.0
0.5
Ra /Rm
R t /Ra
35 ⁄ 8-in. Tool Centered, Active Mode, Thick Beds
68
10
12
Hole diameter (in.)
RLl*Mark of Schlumberger© Schlumberger
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HLLD B h l C ti O H l
RLl-2
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RLl
HLLD Borehole Correction—Open Hole RLl 2
10–1 100 101 102 103 104 105
0.6
0.7
0.8
0.9
1.0
1.1
1.2
HLLD/Rm
R t /HLLD
HLLD Tool Centered (Rm = 0.1 ohm-m)
1.1
1.3
1.5
Borehole Effect, HLLD Tool Centered (Rm = 0.1 ohm-m)
dh
5 in.6 in.8 in.10 in.12 in.14 in.16 in.
dh
6 in.8 in.10 in.12 in.14 in.16 in.18 in.
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HLLS B h l C ti O H l
RLl-3
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RLl
HLLS Borehole Correction—Open Hole
Borehole Effect, HLLS Tool Centered (Rm = 0.1 ohm-m)
dh
6 in.8 in.10 in.
12 in.14 in.16 in.18 in
10–1 100 101 102 103 104 105
0
0.5
1.0
1.5
2.0
2.5
3.0
HLLS/Rm
R t /HLLS
HLLS Tool Centered (Rm = 0.1 ohm-m)
2.0
2.5
3.0
dh
5 in.6 in.8 in.10 in.12 in.14 in.
16 in.
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HRLD Borehole Correction Open Hole
RLl-4
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RLl
HRLD Borehole Correction—Open Hole
HRLD Tool Centered (R m = 0.1 ohm-m)
dh
5 in.6 in.8 in.10 in.12 in.14 in.16 in.
Borehole Effect, HRLD Tool Centered (Rm = 0.1 ohm-m)
10–1 100 101 102 103 104 105
0.4
0.5
0.6
0.7
0.8
1.0
0.9
1.1
R t /HRLD
HRLD/Rm
1.0
1.2
1.4
dh
6 in.8 in.10 in.
12 in.14 in.16 in.18 in
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HRLS Borehole Correction Open Hole
RLl-5
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RLl
HRLS Borehole Correction—Open Hole
HRLS Tool Centered (Rm = 0.1 ohm-m)
dh
5 in.6 in.8 in.10 in.12 in.14 in.16 in.
Borehole Effect, HRLS Tool Centered (Rm = 0.1 ohm-m)
10–1 100 101 102 103 104 105
0
0.5
1.0
1.5
2.0
2.5
3.0
HRLS/Rm
R t /HRLS
2.0
2.5
3.0
R /HRLS
dh
6 in.8 in.10 in.
12 in.14 in.16 in.18 in.
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HLLD Borehole Correction Eccentered in Open Hole
RLl-6
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RLl
HLLD Borehole Correction—Eccentered in Open Hole
dh
5 in.6 in.8 in.10 in.12 in.14 in.16 in.
HLLD Tool Eccentered at Standoff = 0.5 in. (R m = 0.1 ohm-m)
HLLD Tool Eccentered at Standoff = 1.5 in. (R m = 0.1 ohm-m)
1.0
1.1
1.2
R /HLLD
10–1 100 101 102 103 104 105
0.6
0.7
0.8
0.9
1.0
1.1
1.2
HLLD/Rm
R t /HLLD
dh
8 in.10 in.12 in.
14 in.16 in.
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HLLS Borehole Correction—Eccentered in Open Hole
RLl-7
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RLl
HLLS Borehole Correction—Eccentered in Open Hole
0
0.5
1.0
1.5
2.0
2.5
3.0
R t /HLLS
2.0
2.5
3.0
10–1 100 101 102 103 104 105
HLLS/Rm
dh
5 in.6 in.8 in.10 in.12 in.14 in.16 in.
HLLS Tool Eccentered at Standoff = 0.5 in. (R m = 0.1 ohm-m)
dh
8 in.10 in.12 in.
14 in.16 in.
HLLS Tool Eccentered at Standoff = 1.5 in. (R m = 0.1 ohm-m)
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HRLD Borehole Correction—Eccentered in Open Hole
RLl-8
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RLl
HRLD Borehole Correction Eccentered in Open Hole
dh
5 in.6 in.8 in.10 in.12 in.14 in.16 in.
HRLD Tool Eccentered at Standoff = 0.5 in. (R m = 0.1 ohm-m)
0.9
0.8
1.0
1.1
R /HRLD
10–1 100 101 102 103 104 105
0.4
0.6
0.5
0.7
0.8
0.9
1.0
1.1
HRLD/Rm
R t /HRLD
dh
8 in.10 in.12 in.
14 in.16 in.
HRLD Tool Eccentered at Standoff = 1.5 in. (R m = 0.1 ohm-m)
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HRLS Borehole Correction—Eccentered in Open Hole
RLl-9
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RLl
HRLS Borehole Correction Eccentered in Open Hole
0
0.5
1.0
1.5
2.0
2.5
3.0
R t /HRLS
10–1 100 101 102 103 104 105
HRLS/Rm
2.0
2.5
3.0
R /HRLS
HRLS Tool Eccentered Standoff = 0.5 in. (Rm = 0.1 ohm-m)
HRLS Tool Eccentered Standoff = 1.5 in. (Rm = 0.1 ohm-m)
dh
5 in.6 in.8 in.10 in.12 in.14 in.16 in.
dh
8 in.10 in.12 in.
14 in.16 in.
Resistivity Laterolog—Wireline
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole
RLl-10
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RLl
Borehole Correction Open Hole
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA1
Tool Centered
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA1
Standoff = 0.5 in.
RLA1/Rm
General
Resistivity Laterolog—Wireline
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole
RLl-11
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RLl
Borehole Correction Open Hole
dh
5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.
22 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA2
Tool Centered
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA2
Standoff = 0.5 in.
RLA2/Rm
Resistivity Laterolog—Wireline
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole
RLl-12
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RLl
Borehole Correction Open Hole
dh 5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.
22 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA3
Tool Centered
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA3
Standoff = 0.5 in.
RLA3/Rm
Resistivity Laterolog—Wireline
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole
RLl-13
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RLl
p
dh 5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.
22 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA4
Tool Centered
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA4
Standoff = 0.5 in.
RLA4/Rm
Resistivity Laterolog—Wireline
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole
RLl-14
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RLl
p
dh
5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.
22 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA5
Tool Centered
2.0
2.5
3.0
1.5
1.0
0.5
0
R t /RLA5
Standoff = 0.5 in.
RLA5/Rm
Resistivity Laterolog—LWD
GeoSteering* Bit Resistivity—6.75-in. ToolBorehole Correction—Open Hole
RLl-20
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RLl
p
0
0.5
0.7
0.8
0.9
1.1
1.2
1.0
10–2 10–1 100 101 102 103 104 105
Ra /Rm
24-in. bit
18-in. bit
12-in. bit
0 9
1.2
1.0
1.1
R t /Ra
Resistivity Galvanic—Drillpipe
Resistivity Laterolog–LWD
GeoSteering* arcVISION675* Resistivity—6.75-in. ToolBorehole Correction—Open Hole
RLl-21
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RLl
10–2 10–1 100 101 102 103 104 105
Ra /Rm
0
0.5
0.7
0.8
0.9
1.1
1.2
1.0
0 9
1.2
1.0
1.1
R t /Ra
24-in. bit
18-in. bit
12-in. bit
Resistivity Laterolog—LWD
GeoSteering* Bit Resistivity in Reaming Mode—6.75-in. ToolBorehole Correction—Open Hole
RLl-22
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RLl
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
10–2 10–1 100 101 102 103 104 105
R t /Ra
Ra /Rm
arcVISION* tool
Bit
*Mark of Schlumberger© Schlumberger
Resistivity Laterolog—LWD
geoVISION* Resistivity Sub—6.75-in. ToolBorehole Correction—Open Hole
RLl-23
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RLl
2
1
R t /Ra
100 101 102 103 104 105
Ra /Rm
Ring Resistivity (with 81 ⁄ 2-in. bit)2
1
R t /Ra
100 101 102 103 104 105
Ra /Rm
Deep Button Resistivity (with 81 ⁄ 2-in. bit)
2
1
R t /Ra
100 101 102 103 104 105
Medium Button Resistivity (with 81 ⁄ 2-in. bit)2
1
R t /Ra
100 101 102 103 104 105
Shallow Button Resistivity (with 81 ⁄ 2-in. bit)
Borehole diameter (in.)
12
16
18
15
8.510
14
13
8.51011
12
13
14
15
Borehole diameter (in.)
8.5
9.5
10.5
11
12
13
10
9.5
9.25
9
8.5
Borehole diameter (in.)Borehole diameter (in.)
Resistivity Laterolog—LWD
geoVISION* Resistivity Sub—8.25-in. ToolBorehole Correction—Open Hole
RLl-24
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RLl
2
1
R t /Ra
100 100
100 100
101 102 103 104 105
Ra /Rm
Ring Resistivity (with 121
⁄ 4
-in. bit) 2
1
R t /Ra
101 102 103 104 105
Ra /Rm
Deep Button Resistivity (with 121
⁄ 4-in. bit)
2
1
R t /Ra
101 102 103 104 105
Medium Button Resistivity (with 121 ⁄ 4-in. bit)2
1
R t /Ra
101 102 103 104 105
Shallow Button Resistivity (with 121 ⁄ 4-in. bit)
22
12.2516
17
18
19
20
12.2514
15
16
17
18
2019
12.25
13.514
15
16
17
12.25
12.75
13
13.5
14
Borehole diameter (in.) Borehole diameter (in.)
Borehole diameter (in.)Borehole diameter (in.)
Resistivity Laterlog—LWD
GeoSteering* Bit Resistivity—6.75-in. ToolDistance Out of Formation—Open Hole
RLl-25
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RLl
10 ohm-m/4° BUR
100 ohm-m/4° BUR
10 ohm-m/5° BUR
100 ohm-m/5° BUR
10 ohm-m/10° BUR
600
500
400
300
200
100
0
0 2 4 6 8 10 12
Dip angle (°)
Distance (ft)
*Mark of Schlumberger© Schl mberger
General
Resistivity Laterolog—Wireline
CHFR* Cased Hole Formation Resistivity ToolCement Correction—Cased Hole
RLl-50
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RLl
No cement
0.5 in.
0.75 in.
1.5 in.
3 in.
5 in.
0.2
0.4
0.6
0.8
1.2
1.4
1.6
1.0
CHFR Cement Correction Chart (4.5-in.-OD casing)
R t /Rchfr
General
Resistivity Laterolog—Wireline
CHFR* Cased Hole Formation Resistivity ToolCement Correction—Cased Hole
RLl-51
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RLl
0.2
0.4
0.6
0.8
1.2
1.4
1.6
1.0
CHFR Cement Correction Chart (7-in.-OD casing)
R t /Rchfr
No cement
0.5 in.
0.75 in.
1.5 in.
3 in.
5 in.
Resistivity Laterolog—Wireline
CHFR* Cased Hole Formation Resistivity ToolCement Correction—Cased Hole
RLl-52
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RLl
No cement
0.5 in.
0.75 in.
1.5 in.
3 in.
5 in.
0.2
0.4
0.6
0.8
1.2
1.4
1.6
1.0
CHFR Cement Correction Chart (9.625-in.-OD casing)
R t /Rchfr
Resistivity Galvanic—Wireline
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolOperating Range—Open Hole
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RInd
PurposeThis chart is used to determine the limit of application for the AIT
Array Induction Imager Tool measurement in a salt-saturated borehole.
Description When the AIT tool logs a large salt-saturated borehole, the 10- and
20-in. induction curves may well be unusable because of the large
conductive borehole. In a borehole with a diameter (dh) of 8 in.,
the 10- and 20-in. curve data are usable if R t < 300Rm. The ratio
of the true resistivity to the mud resistivity (Rt /Rm) is proportional
to (dh /8)2.
A general rule is that a 12-in. borehole must have a ratio of Rt /Rm
≤ 133 to have usable shallow log data. Additional requirements are
that the borehole must be round and the AIT tool standoff is 2.5 in.
The value of Rt /Rm is further reduced if the borehole is irregular or
the standoff requirement is not met.
Chart RInd-1 summarizes these requirements. The expected
values of Rt, Rm, borehole size, and standoff size are entered to
accurately determine the usable resolution in a smooth hole. The
lower chart summarizes which AIT resistivity tools typically provide
the most accurate deep resistivity data.
Example: Salt-Saturated BoreholeGiven: Borehole size = 10 in., Rt = 5 ohm-m, Rm =
0.0135 ohm-m, and standoff (so) = 2.5 in.
Find: Which, if any, of the AIT curves are valid.
Answer: From the x-axis equation:
Enter the chart on the x-axis at 346 and move upward
to intersect Rt = 5 ohm-m on the y-axis. The intersection
point is in an error zone for which the shallow induction
curves are not valid even in a round borehole. The
deeper induction curves are valid only with a 2-ft or
larger vertical resolution.
The limits for the 1-, 2-, and 4-ft curves are integral to the chart.
As illustrated, a 1-ft 90-in. curve is not usable in a large salt-saturated
borehole. Also, under these conditions, the 1-, 2-, and 4-ft curves can-
not have the same resistivity response.
Example: Freshwater Mud BoreholeGiven: Borehole size = 10 in., Rt = 5 ohm-m, Rm = 0.135 ohm-m,
and standoff (so) = 1.5 in.
Find: Which, if any, of the AIT curves are valid.
Answer: Rt /Rm = 37.0, (dh /8)2 = (10/8)2 = 1.5625, and (1.5/so) =
1.5/1.5 = 1. The resulting value from the x-axis equation
is 37.0 × 1.5625 × 1 = 57.9.
Enter the chart at 57.9 on the x-axis and intersect
Rt = 5 ohm-m on the y-axis. The intersection point is within the limit of the 1-ft vertical resolution boundary.
All the AIT induction curves are usable.
RR
dso
t
m
h
=8
1 5
2
.
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolOperating Range—Open Hole
RInd-1
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RInd
1,000
100
10
1
0.01 0.1 1 10 100 1,000 10,000 100,000
Limit of 4-ft logs
Possible large errorson all logs
Limit of 1-ft logs
Possible large errors on shallow logs and 2-ft limit
Recommended AIT operatingrange (compute standoff
method for smooth holes)
RR
dh t
m
81 5
2
.so
R t
(ohm-m)
R t(ohm-m)
Salt-saturatedboreholeexample
Freshwatermud example
10,000
1,000
100
AIT 2-ft limit
AIT 4-ft limit
AIT 1-ft limit
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolBorehole Correction—Open Hole
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RInd
IntroductionThe AIT tools (AIT-B, AIT-C, AIT-H, AIT-M, Slim Array Induction
Imager Tool [SAIT], Hostile Environment Induction Imager Tool
[HIT], and SlimXtreme* Array Induction Imager Tool [QAIT]) do not
have chartbook corrections for environmental effects. The normal
effects that required correction charts in the past (borehole correc-
tion, shoulder effect, and invasion interpretation) are now all made
using real-time algorithms for the AIT tools. In reality, the charts for
the older dual induction tools were inadequate for the complexity of
environmental effects on induction tools. The very large volume of
investigation required to obtain an adequate radial depth of investiga-
tion to overcome invasion makes the resulting set of charts too exten-
sive for a book of this size. The volume that affects the logs can be tens
of feet above and below the tool. To make useful logs, the effects of the
volume above and below the layer of interest must be carefully removed.
This can be done only by either signal processing or inversion-based
processing. This section briefly describes the wellsite processing and
advanced processing available at computing centers.
Wellsite Processing
Borehole Correction
The first step of AIT log processing is to correct the raw data from
all eight arrays for borehole effects. Borehole corrections for the AIT
tools are based on inversion through an iterative forward model to
find the borehole parameters that best reproduce the logs from the
four shortest arrays—the 6-, 9-, 12-, and 15-in. arrays (Grove and
Minerbo, 1991). The borehole forward model is based on a solution
to Maxwell’s equations in a cylindrical borehole of radius r with the
mud resistivity (Rm) surrounded by a homogeneous formation of
resistivity Rf . The tool can be located anywhere in the borehole, but
is parallel to the borehole axis at a certain tool standoff (so). The
Because the AIT borehole model is a circular hole, either axis
from a multiaxis caliper can be used. If the tool standoff is adequate,
the process finds the circular borehole parameters that best match
the input logs. Control of adequate standoff is important because
the changes in the tool reading are very large for small changes in
tool position when the tool is very close to the borehole wall. Near
the center of the hole the changes are very small. A table of rec-
ommended standoff sizes is as follows.
Each type of AIT tool requires a slightly different approach to
the borehole correction method. For example, the AIT-B tool requires
the use of an auxiliary Rm measurement (Environmental
Measurement Sonde [EMS]) to compute Rm or to compute hole
size by using a recalibration of the mud resistivity method internal
to the borehole correction algorithm. The Platform Express*,
SlimAccess*, and Xtreme* AIT tools have integral Rm sensors that
meet the accuracy requirements for the compute standoff mode.
AIT Tool Recommended Standoff
Hole Size (in.) Recommended Standoff (in.)AIT-B, AIT-C, AIT-H, AIT-M, HIT SAIT, QAIT
<5.0 – 0.5
5.0 to 5.5 – 1.0
5.5 to 6.5 0.5 1.5
6.5 to 7.75 1.0 2.0
7.75 to 9.5 1.5 2.5
9.5 to 11.5 2.0 + bowspring† 2.5
>11.5 2.5 + bowspring† 2.5
Note: Do not run AIT tools slick.† Only for AIT-H tool
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolBorehole Correction—Open Hole
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RInd
ties, with the crossover occurring between 100 and 200 mS/m. The
use of the R-signal at low conductivities overcomes the errors in
the X-signal associated with the normal magnetic susceptibilities
of sedimentary rock layers (Barber et al., 1995).
The weights w in the equation can profit from further refine-
ment. The method used to compute the weights introduces a small
amount of noise in the matrix inversion, so the fit is about ±1% to
±2% to the defined target response. A second refinement filter is
used to correct for this error. The AIT wellsite processing sequence,
from raw, calibrated data to corrected logs, is shown in Fig. 1.
(Freedman and Minerbo, 1991, 1993; Zhang et al., 1994). Maximum-
Entropy Resistivity Log Inversion (MERLIN) processing (Barber et
al., 1999) follows Freedman and Minerbo (1991) closely, and that
paper is the basic reference for the mathematical formulation. The
problem is set up as the simplest parametric model that can fit the
data: a thinly layered formation with each layer the same thickness
(Fig. 2). The inversion problem is to solve for the conductivity of
each layer so that the computed logs from the layered formation
are the closest match to the measured logs.
10 in.
20 in.
30 in.
60 in.90 in.
28 channels(AIT-B, -C, and -D)16 channels
(all others)
Skineffect
correction
Multichannelsignal
processingand 2D
processing
14or8
28or16
Boreholecorrection
Caliper
Rm
Standoff
A(H)IFC
R-signals only
R-signalsX-signals
28or16
Five depths(10 to 90 in.)
Five depths(10 to 90 in.)
Exceptionhandling and
environmentally
compensatedlog processing
Rm
Caliper
Raw BHC signals
+
Figure 1. Block diagram of the real-time log processing chain from raw, calibrated array data to finished logs.
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolBorehole Correction—Open Hole
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Rxo
Rxo
R t
ri
Formation
resistivity
Distance from wellbore
Step Profile
Slope Profile
r1
RInd
Borehole-correctedR- and X-signals
Model parameters
Sensitivitymatrix
Update model
parameters
No
28 or 16 channels
Computedlog within 1%
of measuredlog?
Computed log
Forward model
Initial guess
ComputeLagrangian
The flow of MERLIN processing is shown in Fig. 3. The borehole-
corrected raw resistive and reactive (R- and X-) signals are used as
a starting point. The conductivity of a set of layers is estimated from
the log values, and the iterative modeling is continued until the logs
converge. The set of formation layer conductivity values is then con-
verted to resistivity and output as logs.
Invasion Processing
The wellsite interpretation for invasion is a one-dimensional (1D)inversion of the processed logs into a four-parameter invasion model
(R xo, Rt, r1, and r2, shown in Fig. 4). The forward model is based on
the Born model of the radial response of the tools and is accurate for
most radial contrasts in which induction logs should be used. The
inversion can be run in real time. The model is also available in the
Invasion Correction module of the GeoFrame* Invasion 2 application,
which also includes the step-invasion model and annulus model (Fig. 4).
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolBorehole Correction—Open Hole
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RInd
R t0
∞
∞
R t1
R t2
Rxo1
Rxo2
Rm
Rm
Another approach is also used in the Invasion 2 application mod-
ule. If the invaded zone is more conductive than the noninvaded
zone, some 2D effects on the induction response can complicate
the 1D inversion. Invasion 2 conducts a full 2D inversion using a
2D forward model (Fig. 5) to produce a more accurate answer for
situations of conductive invasion and in thin beds.
References Anderson, B., and Barber, T.: Induction Logging, Sugar Land, TX,
USA, Schlumberger SMP-7056 (1995).
Barber, T.D.: “Phasor Processing of Induction Logs Including
Shoulder and Skin Effect Correction,” US Patent No. 4,513,376
(September 11, 1984).
Barber, T., et al.: “Interpretation of Multiarray Induction Logs in
Invaded Formations at High Relative Dip Angles,” The Log Analyst,
(May–June 1999) 40, No. 3, 202–217.
Barber, T., Anderson, B., and Mowat, G.: “Using Induction Tools toIdentify Magnetic Formations and to Determine Relative Magnetic
Susceptibility and Dielectric Constant,” The Log Analyst
(July–August 1995) 36, No. 4, 16–26.
Barber, T., and Rosthal, R.: “Using a Multiarray Induction Tool to
Achieve Logs with Minimum Environmental Effects,” paper SPE 22725
presented at the SPE Annual Technical Conference and Exhibition,
Dallas, Texas, USA (October 6–9, 1991).
Dyos, C.J.: “Inversion of the Induction Log by the Method of MaximumEntropy,” Transactions of the SPWLA 28th Annual Logging
Symposium, London, UK (June 29–July 2, 1987), paper T.
Freedman, R., and Minerbo, G.: “Maximum Entropy Inversion of the
Induction Log,” SPE Formation Evaluation (1991), 259–267; also
paper SPE 19608 presented at the SPE Annual Technical Conference
and Exhibition, San Antonio, TX, USA (October 8–11, 1989).
Freedman, R., and Minerbo, G.: “Method and Apparatus for
Producing a More Accurate Resistivity Log from Data Recorded by anInduction Sonde in a Borehole,” US Patent 5,210,691 (January 1993).
Figure 5. The parametric 2D formation model used in Invasion 2.
arcVISION475* and ImPulse* 43 ⁄ 4-in. ArrayResistivity Compensated Tools—2 MHzB h l C ti O H l
Resistivity Electromagnetic—LWD
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Borehole Correction—Open Hole
PurposeThis chart is used to determine the borehole correction applied
by the surface acquisition system to arcVISION475 and ImPulsephase-shift (Rps) and attenuation resistivity (Rad) curves on the
log. The value of Rt is used in the calculation of water saturation.
DescriptionEnter the appropriate chart for the borehole environmental condi-
tions and tool used to measure the various formation resistivities
with the either the uncorrected phase-shift or attenuation resistivity
value (not the resistivity shown on the log) on the x-axis. Move upward
to intersect the appropriate resistivity spacing line, and then movehorizontally left to read the ratio value on the y-axis. Multiply the
ratio value by the resistivity value entered on the x-axis to obtain Rt.
Charts REm-12 through REm-38 are used similarly to Chart
REm-11 for different borehole conditions and arcVISION* and
ImPulse tool combinations.
ExampleGiven: Rps = 400 ohm-m (uncorrected) from arcVISION475
(2-MHz) phase-shift 10-in. resistivity, borehole size =6 in., and mud resistivity (Rm) = 0.02 ohm-m at forma-
tion temperature.
Find: Formation resistivity (Rt).
Answer: Enter the top left chart at 400 ohm-m on the x-axis
and move upward to intersect the 10-in. resistivity
curve (green).
Move left and read approximately 1.075 on the y-axis.
Rt = 1.075 × 400 = 430 ohm-m.
REm
Resistivity Electromagnetic—LWD
arcVISION475* and ImPulse* 43 ⁄ 4-in. ArrayResistivity Compensated Tools—2 MHzBorehole Correction Open Hole
REm–11
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REm
Borehole Correction—Open Hole
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 6 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 6 in., Rm = 0.1 ohm-m
arcVISION475* and ImPulse* 43 ⁄ 4-in. ArrayResistivity Compensated Tools—2 MHzBorehole Correction Open Hole
REm-12
Resistivity Electromagnetic—LWD
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Borehole Correction—Open Hole
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 7 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 7 in., Rm = 0.1 ohm-m
arcVISION475 and ImPulse Borehole Correction for 2 MHz d 7 in R 1 0 ohm m
REm
Resistivity Electromagnetic—LWD
arcVISION475* and ImPulse* 43 ⁄ 4-in. ArrayResistivity Compensated Tools—2 MHzBorehole Correction—Open Hole
REm-13
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REm
Borehole Correction—Open Hole
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 8 in., Rm = 0.02 ohm-m
10 –1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 8 in., Rm = 0.1 ohm-m
S
Resistivity Electromagnetic—LWD
arcVISION475* and ImPulse* 43 ⁄ 4-in. ArrayResistivity Compensated Tools—2 MHzBorehole Correction—Open Hole
REm-14
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REm
Borehole Correction Open Hole
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.1 ohm-m
VISION475 d I P l B h l C ti f 2 MH d 10 i R 1 0 h
Resistivity Electromagnetic—LWD
arcVISION675* 63 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-15
8/21/2019 Log Interpretation Charts
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REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 400 kHz, dh = 8 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION675 Borehole Correction for 400 kHz, dh = 8 in., Rm = 0.1 ohm-m
VISION6 B h l C i f 00 kH d 8 i R 0 h
Resistivity Electromagnetic—LWD
arcVISION675* 63 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-16
8/21/2019 Log Interpretation Charts
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REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 400 kHz, dh = 10 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION675 Borehole Correction for 400 kHz, dh = 10 in., Rm = 0.1 ohm-m
VISION675 B h l C ti f 400 kH d 10 i R 1 0 h
General
Resistivity Electromagnetic—LWD
arcVISION675* 63 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-17
8/21/2019 Log Interpretation Charts
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REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION675 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 400 kHz d 12 in R 1 0 ohm m
Resistivity Electromagnetic—LWD
arcVISION675* 63 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-18
8/21/2019 Log Interpretation Charts
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REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 400 kHz, dh = 14 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION675 Borehole Correction for 400 kHz, dh = 14 in., Rm = 0.1 ohm-m
VISION675 B h l C ti f 400 kH d 14 i R 1 0 h
Resistivity Electromagnetic—LWD
arcVISION675* 63 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-19
8/21/2019 Log Interpretation Charts
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REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 2 MHz, dh = 8 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION675 Borehole Correction for 2 MHz, dh = 8 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 2 MHz d 8 in R 1 0 ohm m
Resistivity Electromagnetic—LWD
arcVISION675* 63 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHzBed Thickness Correction—Open Hole
REm-20
8/21/2019 Log Interpretation Charts
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REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION675 Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.1 ohm-m
VISION675 B h l C i f 2 MH d 10 i R 1 0 h
Resistivity Electromagnetic—LWD
arcVISION675* 63 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-21
8/21/2019 Log Interpretation Charts
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REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.05 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION675 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.1 ohm-m
VISION675 B h l C ti f 2 MH d 12 i R 1 0 h
Resistivity Electromagnetic—LWD
arcVISION675* 63 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-22
8/21/2019 Log Interpretation Charts
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REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 2 MHz, dh = 14 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
R t /Rps R t /Rad
R t /Rps R t /Rad
arcVISION675 Borehole Correction for 2 MHz, dh = 14 in., Rm = 0.1 ohm-m
Resistivity Electromagnetic—LWD
arcVISION825* 81 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-23
8/21/2019 Log Interpretation Charts
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REm
arcVISION825 Borehole Correction for 400 kHz, dh = 10 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 400 kHz, dh = 10 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION825 B h l C i f 400 kH d 10 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION825* 81 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHzBed Thickness Correction—Open Hole
REm-24
8/21/2019 Log Interpretation Charts
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REm
arcVISION825 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
arcVISION825 Borehole Correction for 400 kHz d 12 in R 1 0 ohm m
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION825* 81 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-25
8/21/2019 Log Interpretation Charts
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REm
arcVISION825 Borehole Correction for 400 kHz, dh = 14 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 400 kHz, dh = 14 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION825 B h l C ti f 400 kH d 14 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION825* 81 ⁄ 4-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-26
8/21/2019 Log Interpretation Charts
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REm
arcVISION825 Borehole Correction for 400 kHz, dh = 18 in., R
m = 0.02 ohm-m
arcVISION825 Borehole Correction for 400 kHz, dh = 18 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION825 B h l C ti f 400 kH d 18 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION825* 81 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-27
8/21/2019 Log Interpretation Charts
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REm
arcVISION825 Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION825* 81 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-28
8/21/2019 Log Interpretation Charts
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REm
arcVISION825 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION825 B h l C ti f 2 MH d 12 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION825* 81 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-29
8/21/2019 Log Interpretation Charts
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REm
arcVISION825 Borehole Correction for 2 MHz, dh = 14 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 2 MHz, dh = 14 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION825 B h l C ti f 2 MH d 14 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION825* 81 ⁄ 4-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-30
8/21/2019 Log Interpretation Charts
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REm
arcVISION825 Borehole Correction for 2 MHz, dh = 18 in., R
m = 0.02 ohm-m
arcVISION825 Borehole Correction for 2 MHz, dh = 18 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rad (ohm-m)
arcVISION825 Borehole Correction for 2 MHz d 18 in R 1 0 ohm m
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-31
8/21/2019 Log Interpretation Charts
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REm
arcVISION900 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION900 B h l C i f 400 kH d 12 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-32
8/21/2019 Log Interpretation Charts
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REm
arcVISION900 Borehole Correction for 400 kHz, dh = 15 in., R
m = 0.02 ohm-m
arcVISION900 Borehole Correction for 400 kHz, dh = 15 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 400 kHz d 15 in R 1 0 ohm m
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-33
8/21/2019 Log Interpretation Charts
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REm
arcVISION900 Borehole Correction for 400 kHz, dh = 18 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 400 kHz, dh = 18 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 400 kHz d 18 in R 1 0 ohm m
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Array Resistivity Compensated Tool—400 kHzBorehole Correction—Open Hole
REm-34
8/21/2019 Log Interpretation Charts
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REm
arcVISION900 Borehole Correction for 400 kHz, dh = 22 in., R
m = 0.02 ohm-m
arcVISION900 Borehole Correction for 400 kHz, dh = 22 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION900 B h l C ti f 400 kH d 22 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION900* 9-in.Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-35
8/21/2019 Log Interpretation Charts
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REm
arcVISION900 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 2 MHz d 12 in R 1 0 ohm m
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-36
8/21/2019 Log Interpretation Charts
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REm
arcVISION900 Borehole Correction for 2 MHz, dh = 15 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 2 MHz, dh = 15 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION900 B h l C i f 2 MH d 15 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-37
8/21/2019 Log Interpretation Charts
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REm
arcVISION900 Borehole Correction for 2 MHz, dh = 18 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 2 MHz, dh = 18 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION900 B h l C ti f 2 MH d 18 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Array Resistivity Compensated Tool—2 MHzBorehole Correction—Open Hole
REm-38
8/21/2019 Log Interpretation Charts
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REm
arcVISION900 Borehole Correction for 2 MHz, dh = 22 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 2 MHz, dh = 22 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
R t /Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
R t /Rad
Rad (ohm-m)
VISION900 B h l C ti f 2 MH d 22 i R 1 0 h
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity Electromagnetic—LWD
arcVISION675*, arcVISION825*, and arcVISION900*Array Resistivity Compensated Tools—400 kHzBed Thickness Correction—Open Hole
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REm
PurposeThis chart is used to determine the correction factor applied by the
surface acquisition system for bed thickness to the phase-shift andattenuation resistivity on the logs of arcVISION675, arcVISION825,
and arcVISION900 tools.
DescriptionThe six bed thickness correction charts on this page are paired for
phase-shift and attenuation resistivity at different values of true (Rt)
and shoulder bed (Rs) resistivity. Only uncorrected resistivity values
are entered on the chart, not the resistivity shown on the log.
Chart REm-56 is also used to find the bed thickness correctionapplied by the surface acquisition system for 2-MHz arcVISION* and
ImPulse* logs.
ExampleGiven: Rt /Rs = 10/1, Rps uncorrected = 20 ohm-m (34 in.), and
bed thickness = 6 ft.Find: Rt.
Answer: The appropriate chart to use is the phase-shift resistivity
chart in the first row, for Rt = 10 ohm-m and Rs = 1 ohm-m.
Enter the chart on the x-axis at 6 ft and move upward
to intersect the 34-in. spacing line. The corresponding
value of Rt /Rps is 1.6; Rt = 20 × 1.6 = 32 ohm-m.
arcVISION675*, arcVISION825*, and arcVISION900*Array Resistivity Compensated Tools—400 kHzBed Thickness Correction—Open Hole
REm-55
Resistivity Electromagnetic—LWD
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Phase-Shift Resistivity Attenuation Resistivity
Attenuation Resistivity
arcVISION675, arcVISION825, and arcVISION900 400-kHzBed Thickness Correction for R t = 10 ohm-m and Rs = 1 ohm-m at Center of Bed
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
R t /Rps R t /Rad
Bed thickness (ft)
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Bed thickness (ft)
Phase-Shift Resistivity
arcVISION675, arcVISION825, and arcVISION900 400-kHzBed Thickness Correction for R t = 1 ohm-m and Rs =10 ohm-m at Center of Bed
2.0
1.5
1.0
0.5
0
R t /Rps R t /Rad
2.0
1.5
1.0
0.5
0
REm
Resistivity Electromagnetic—LWD
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzBed Thickness Correction—Open Hole
REm-56
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REm
Phase-Shift Resistivity Attenuation Resistivity
Attenuation Resistivity
arcVISION and ImPulse 2-MHz Bed Thickness Correction forR t = 10 ohm-m and Rs =1 ohm-m at Center of Bed
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
R t /Rps R t /Rad
Bed thickness (ft)
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Bed thickness (ft)
Phase-Shift Resistivity
arcVISION and ImPulse 2-MHz Bed Thickness Correction forR t = 1 ohm-m and Rs =10 ohm-m at Center of Bed
2.0
1.5
1.0
0.5
0
R t /Rps R t /Rad
2.0
1.5
1.0
0.5
0
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array ResistivityCompensated Tools—2 MHz and 16-in. SpacingDielectric Correction—Open Hole
REm-58
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REm
8.20
8.25
8.30
8.35
8.40
8.45
8.50
8.55
8.60
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
150
175
200
225
3 0
5 0
7 0
1 0 0
1 5
2 0
1 ,
0 0 0
1 0 ,
0 0 0
R t
o
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array ResistivityCompensated Tools—2 MHz and 22-in. SpacingDielectric Correction—Open Hole
REm-59
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REm
6.5
6.6
6.7
6.8
6.9
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
150
3 0
5 0
7 0
1 0 0
1 5
2 0
1 , 0
0 0
1 0 ,
0 0 0
o
R t
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array ResistivityCompensated Tools—2 MHz and 28-in. SpacingDielectric Correction—Open Hole
REm-60
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REm
o
5.1
5.2
5.3
5.4
5.5
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
150
175
3 0
5 0
7 0
1 0 0
2 0
1 ,
0 0 0
1 0 ,
0 0 0
R t
o
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array ResistivityCompensated Tools—2 MHz and 34-in. SpacingDielectric Correction—Open Hole
REm-61
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REm4.2
4.3
4.4
4.5
4.6
4.7
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
3 0
5 0
7 0
1 0 0
1 5
2 0
1 , 0
0 0
1 0 ,
0 0 0
o
R t
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array ResistivityCompensated Tools—2 MHz and 40-in. SpacingDielectric Correction—Open Hole
REm-62
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REm
3.4
3.5
3.6
3.7
3.8
3.9
4.0
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
3 0
5 0
7 0
1 0 0
1 5
2 0
1 ,
0 0 0
1 0 ,
0 0 0
R t
o
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array ResistivityCompensated Tools—2 MHz with Dielectric AssumptionDielectric Correction—Open Hole
REm-63
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REm
10–1
1.0
1.5
2.0
2.5
3.0
3.5
Dielectric Effects of Standard Processed arcVISION675 or ImPulse Log
at 2 MHz with Dielectric Assumption
100 101 102 103 104
R t /Rps
Rps (ohm-m)
3.5
0.5
16 in.
22 in.
28 in.
34 in.
40 in.
Resistivityspacing
Resistivityspacing
Dielectric assumptionεr = 5 + 108.5R–0.35
ε1 = 2εr
ε2 = 0.5εr
o
General
Formation Resistivity—Wireline
Resistivity GalvanicInvasion Correction—Open Hole
Rt-1(former Rint-1)
Purpose If S A and S R are equal the assumption of a step contact inva
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Purpose
The charts in this chapter are used to determine the correction for
invasion effects on the following parameters: diameter of invasion (di) ratio of flushed zone to true resistivity (R xo /Rt) Rt from laterolog resistivity tools.
The R xo /Rt and Rt values are used in the calculation of water
saturation.
DescriptionThe invasion correction charts, also referred to as “tornado” or “but-
terfly” charts, assume a step-contact profile of invasion and that allresistivity measurements have already been corrected as necessary
for borehole effect and bed thickness by using the appropriate chart
from the “Resistivity Laterolog” chapter.
To use any of these charts, enter the y-axis and x-axis with the
required resistivity ratios. The point of intersection defines di,
R xo /Rt, and Rt as a function of one resistivity measurement.
Saturation Determination in Clean Formations
Either of the chart-derived values of Rt and R xo /Rt are used to find values for the water saturation of the formation (S w ). The first of two
approaches is the S w -Archie (S wA ), which is found using the Archie
saturation formula (or Chart SatOH-3) with the derived Rt value and
known values of the formation resistivity factor (FR) and the resistiv-
ity of the water (R w ). The S w -ratio (S wR) is found by using R xo /Rt and
Rmf /R w as in Chart SatOH-4.
If S wA and S wR are equal, the assumption of a step-contact inva-
sion profile is indicated to be correct, and all values determined
(S w , Rt, R xo, and di) are considered good.If S wA > S wR, either invasion is very shallow or a transition-type
invasion profile is indicated, and S wA is considered a good value for S w .
If S wA < S wR, an annulus-type invasion profile may be indicated,
and a more accurate value of water saturation may be estimated
by using
The correction factor of (S wA /S wR)1 ⁄4 is readily determined from
the scale.
For more information, see Reference 9.
SwA /SwR
S SS
S wcor wA wA
wR
=
1
4
Formation Resistivity—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)Formation Resistivity and Diameter of Invasion—Open Hole
Rt-2
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0.2
0.5
5
10
20
50
100
200
500
1,000
8 15 18 20 22 24 28 32 3640
45
50
60
80
100
120
di (in.)
2
103
102
101
100
HLLD/Rxo
Thick Beds, 8-in. Hole, Rxo /Rm = 10
R t /Rxo
Formation Resistivity—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)Formation Resistivity and Diameter of Invasion—Open Hole
Rt-3
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Thick Beds, 8-in. Hole, Rxo /Rm = 10
HRLD/Rxo
di (in.)
1,000
8 15 18 20 22 24 28 32 3640
45
50
60
80
100
120
0.2
0.5
2
103
102
101
100
500
200
100
50
20
10
5
R t /Rxo
Formation Resistivity—LWD
geoVISION675* ResistivityFormation Resistivit y and Diameter of Invasion—Open Hole
Rt-10
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Ring, Deep, and Medium Button Resistivity (6.75-in. tool)
10
1
2
3
5
6
7
8
9
4Rring /Rbm
10070
50
30
20
15
10
7
5
3
2
24
22
20
1817
16
15
14
13
12
di
3.0
2.42.01.81.6
1.5
1.4
1.3
1.2
R t /Rring
R t /Rxo
Rxo /Rm = 50
dh = 8.5 in.
Formation Resistivity—LWD
geoVISION675* ResistivityFormation Resistivity and Diameter of Invasion—Open Hole
Rt-11
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Deep, Medium, and Shallow Button Resistivity (6.75-in. tool)
30
1
3
5
6
8
7
910
20
4
Rbd /Rbs
2
10070
50
30
20
15
10
7
5
3
18
17
16
151413
12
11
1.6
1.51.41.31.2
1.1
di
2
1
R t /Rbd
R t /Rxo
Rxo /Rm = 50dh = 8.5 in.
Formation Resistivity—LWD
geoVISION675* ResistivityFormation Resistivity and Diameter of Invasion—Open Hole
Rt-12
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Bit, Ring, and Deep Button Resistivity (6.75-in. tool) with ROP to Bit Face = 4 ft
10
1
2
3
5
67
8
9
4Rbit /Rbd
24
10070
50
30
20
15
10
7
5
3
2
1
50
40
34
28
22
20
18
16
4.03.0
2.5
2.0
1.8
1.6
1.4
di
R t /Rbit
R t /Rxo
Rxo /Rm = 50
dh = 8.5 in.
Formation Resistivity—LWD
geoVISION675* ResistivityFormation Resistivity and Diameter of Invasion—Open Hole
Rt-13
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Bit, Ring, and Deep Button Resistivity (6.75-in. tool) with ROP to Bit Face = 35 ft
1
3
5
6
8
7
910
20
4
Rbit /Rbd
2
24
22
1.4
1.3
100
70
50
30
20
15
10
7
5
3
2
1
70
5034
28
20
18
16
2.42.0
1.6
1.2
Rxo /Rm = 50dh = 8.5 in.
di
R t /Rbit
R t /Rxo
Formation Resistivity—LWD
geoVISION825* 81 ⁄ 4-in. Resistivity-at-the-Bit ToolFormation Resistivity and Diameter of Invasion—Open Hole
Rt-14
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Ring, Deep, and Medium Button Resistivity (81 ⁄ 4-in. tool)
10
1
2
3
5
6
7
8
9
4
Rring /Rbm
1.2
17
10070
50
30
20
15
10
7
5
3
2
1
30
26
242322
21
20
19
18
16
3.0
2.41.8
1.6
1.4
1.3
R t /R
ring
di
R t /Rxo
Rxo /Rm = 50dh = 12.25 in.
Formation Resistivity—LWD
geoVISION825* 81 ⁄ 4-in. Resistivity-at-the-Bit ToolFormation Resistivity and Diameter of Invasion—Open Hole
Rt-15
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Deep, Medium, and Shallow Button Resistivity (81 ⁄ 4-in. tool)
1
3
5
6
8
7
910
20
4
Rbd /Rbs
2
10070
50
30
20
15
10
7
5
3
2
1
24
22
2019
18
17
16
14
2.4
2.0
1.61.41.3
1.2
1.1
di
R t /Rbd
R t
/Rxo
Rxo /Rm = 50
dh = 12.25 in.
Formation Resistivity—LWD
geoVISION825* 81 ⁄ 4-in. Resistivity-at-the-Bit ToolFormation Resistivity and Diameter of Invasion—Open Hole
Rt-16
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10
1
2
3
5
6
7
8
9
4
Rbit /Rbd
Bit, Ring, and Deep Button Resistivity (81 ⁄ 4-in. tool) with ROP to Bit Face = 4 ft
10070
50
30
20
15
10
7
5
3
2
60
50
40
35
30
28
26
24
22
20
5.0
3.02.4
2.0
1.8
1.6
1.5
1.4
1.3
1
di
R t /Rbit
R t /Rxo
Rxo /Rm = 50
dh = 12.25 in.
Formation Resistivity—LWD
geoVISION825* 81 ⁄ 4-in. Resistivity-at-the-Bit ToolFormation Resistivity and Diameter of Invasion—Open Hole
Rt-17
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Bit, Ring, and Deep Button Resistivity (81 ⁄ 4-in. tool) with ROP to Bit Face = 35 ft
1
3
5
6
8
7
910
20
4
Rbit /Rbd
2
R t /Rxo = 50
dh = 12.25 in.
di
R t /Rbit
R t /Rxo
100
70
50
30
20
15
10
7
5
3
2
1
70
5040
35
30
28
26
24
22
20
3.02.0
1.6
1.4
1.3
1.2
arcVISION* Array Resistivity Compensated Tool—400 kHzResistivity Anisotropy Versus Shale Volume—Open Hole
Rt-31
Formation Resist ivity—LWD
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101
Attenuation Resistivity
0 0.2 0.4 0.6 0.8 1.0100
101Phase-Shift Resistivity
Rps (ohm-m)
Vsh
Response Through Sand and Shale Layers at 90° Relative Dip
for Rsh = 1 ohm-m and Rsand = 5 ohm-m
100
Rad
(ohm-m)
0 0 2 0 4 0 6 0 8 1 0
Attenuation Resistivity
Phase-Shift Resistivity
Response Through Sand and Shale Layers at 90° Relative Dip
for Rsh = 1 ohm-m and Rsand = 20 ohm-m
101
100
0
Rps
(ohm-m)
0.2 0.4 0.6 0.8 1.0
Vsh
102
101
100
0
Rad
(ohm-m)
0 2 0 4 0 6 0 8 1 0
102
Formation Resistivity—LWD
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzResistivity Anisotropy Versus Shale Volume—Open Hole
Rt-32
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Phase-Shift Resistivity
Response Through Sand and Shale Layers at 90° Relative Dipfor Rsh = 1 ohm-m and Rsand = 20 ohm-m
101
100
102
101
100
102Phase-Shift Resistivity
Response Through Sand and Shale Layers at 90° Relative Dipfor Rsh = 1 ohm-m and Rsand = 5 ohm-m
101
100
102
101
100
102
0 0.2 0.4 0.6 0.8 1.0
Vsh
Rps
(ohm-m)
0
Rps
(ohm-m)
0.2 0.4 0.6 0.8 1.0
Vsh
Attenuation ResistivityAttenuation Resistivity
Rad
(ohm-m)
Rad
(ohm-m)
0 6 0 8 0
arcVISION* Array Resistivity Compensated Tool—400 kHzResistivity Anisotropy Versus Dip—Open Hole
Rt-33
Formation Resistivity—LWD
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Phase-Shift Resistivity
Aniostropy Response for Rh = 1 ohm-m and (Rv /Rh) = 5
101
100
0 2010 40 60 80 90
Relative dip angle (°)
103
102
30 50 70 0 2010 40 60 80 90
Relative dip angle (°)
30 50 70
Attenuation Resistivity Attenuation Resistivity103
101
100
102
Phase-Shift Resistivity
Aniostropy Response for Rh = 1 ohm-m and (Rv /Rh) = 2
100
101
100
101
Rps
(ohm-m)
Rad
(ohm-m)
Rps
(ohm-m)
Rad
(ohm-m)
Formation Resist ivity—LWD
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzResistivity Anisotropy Versus Dip—Open Hole
Rt-34
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Phase-Shift Resistivity
Aniostropy Response for Rh = 1 ohm-m and (Rv /Rh) = 5
Phase-Shift Resistivity
Aniostropy Response for Rh = 1 ohm-m and (Rv /Rh) = 2
101
100
103
102
103
101
102
Rps
(ohm-m)
Rad
(ohm-m)
0 2010 40 60 80 90
Relative dip angle (°)
30 50 70
100
101
101
Rps
(ohm-m)
Rad
(ohm-m)
0 2010 40 60 80 90
Relative dip angle (°)
30 50 70
Attenuation Resistivity Attenuation Resistivity
Formation Resistivity—LWD
arcVISION* Array Resistivity Compensated Tool—400 kHzResistivity Anisotropy Versus Square Root of Rv /Rh—Open Hole
Rt-35
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Phase-Shift Resistivity
Aniostropy Response at 85° dip for Rh = 1 ohm-m
101
100
1.0
Rps
(ohm-m)
2.01.5 3.0 4.0 5.0
(Rv /Rh)
103
102
101
100
Rad
(ohm-m)
103
102
2.5 3.5 4.5 1.0 2.01.5 3.0 4.0 5.02.5 3.5 4.5
Attenuation Resistivity Attenuation Resistivity
Phase-Shift Resistivity
Aniostropy Response at 65° dip for Rh = 1 ohm-m
100
Rps
(ohm-m)
101
101
100
Rad
(ohm-m)
(Rv /Rh)
Formation Resistivity—LWD
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzResistivity Anisotropy Versus Square Root of Rv /Rh—Open Hole
Rt-36
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Phase-Shift Resistivity
Aniostropy Response at 85° dip for Rh = 1 ohm-m
Phase-Shift Resistivity
Aniostropy Response at 65° dip for Rh = 1 ohm-m
1.0 2.01.5 3.0 4.0 5.02.5 3.5 4.5 1.0 2.01.5 3.0 4.0 5.0
(Rv /Rh)
2.5 3.5 4.5
Attenuation Resistivity Attenuation Resistivity
101
100
Rps
(ohm-m)
103
102
101
100
Rad
(ohm-m)
103
102
100
Rps
(ohm-m)
101
101
100
Rad
(ohm-m)
(Rv /Rh)
Formation Resistivity—LWD
arcVISION675* Array Resistivity Compensated Tool—400 kHzConductive Invasion—Open Hole
Rt-37
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16-in. Rps /40-in. Rad 0.1
1.0
Rxo and di for R t ~ 10 ohm-m
16
20
2428
32
364044
48
52
56
60
64
0.15
0.2
0.3
0.5
0.7
1
1.5
2
3
5
7
0.95
0.9
0.80.85
0.750.7
0.650.6
0.55
40-in. Rad /R t = 1
di (in.)
Rxo = 0.1 ohm−m
Formation Resistivity—LWD
arcVISION675* and ImPulse* Array Resistivity Compensated Tools—2 MHzConductive Invasion—Open Hole
Rt-38
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16-in. Rps /40-in. Rad
1.0
Rxo and di for R t ~ 10 ohm-m
0.3
0.5
7
0.7
1
1.5
2
3
5
16
40
44
48 52
d (in )
56
0.2
40-in. Rad /R t = 1
0.9
0.8
0.7
0.6
0.2
0.1
Formation Resistivity—LWD
arcVISION* Array Resistivity Compensated Tool—400 kHzResistive Invasion—Open Hole
Rt-39
R d d f R 10 h
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40
45
50
55
60
65
70
75
80
90
100
125
200
150
100
70
50di (in.)
Rxo = 300 ohm-m
16-in. Rps /40-in. Rad
10
Rxo and di for R t ~ 10 ohm-m
0 95
0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
Formation Resistivity—LWD
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzResistive Invasion—Open Hole
Rt-40
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16-in. Rps /40-in. Rad
Rxo and di for R t ~ 10 ohm-m
1.6
2.0
2.2
2.4
1.8
40
55
60
di (in.)
200
150
100
70
5035
45
0.8
0.75
0.7
0.65
0.55
0.6
50
65
Rxo = 300 ohm-m
arcVISION* Array Resistivity Compensated Tool—400 kHz in Horizontal WellBed Proximity Effect—Open Hole
Formation Resistivity—LWD
Purpose
Charts Rt 41 and Rt 42 are used to calculate the correction applied
Example
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Charts Rt-41 and Rt-42 are used to calculate the correction applied
to the log presentation of Rt from the arcVISION tool at theapproach to a bed boundary. The value of Rt is used to calculate
water saturation.
Description
There are two sets of charts for differing conditions:
shoulder bed resistivity (Rshoulder) = 10 ohm-m and Rt = 1 ohm-m
Rshoulder = 10 ohm-m and Rt =100 ohm-m.
Given: Rshoulder = 10 ohm-m, Rt = 1 ohm-m, and
16-in. Rps = 1.5 ohm-m.
Find: Bed proximity effect.
Answer: The top set of charts is appropriate for these resistivity
values. The ratio Rps /Rt = 1.5/1 = 1.5.
Enter the y-axis of the left-hand chart at 1.5 and move
horizontally to intersect the 16-in. curve. The corre-
sponding value on the x-axis is 1 ft, which is the distance
of the surrounding bed from the tool. At 2 ft from the
bed boundary, the value of 16-in. Rps = 1 ohm-m.
Formation Resistivity–Drill Pipe
Formation Resistivity—LWD
arcVISION* Array Resistivity Compensated Tool—400 kHz in Horizontal WellBed Proximity Effect—Open Hole
Rt-41
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0 1 2 3 4 5 6 7 8 9 100
1
2
3
Distance to bed boundary (ft)
0 1 2 3 4 5 6 7 8 9 10
Rps /R t
Bed Proximity Effect for Horizontal Well: Rshoulder = 10 ohm-m and R t = 1 ohm-m
0 1 2 3 4 5 6 7 8 9 100
1
2
3
Distance to bed boundary (ft)
Rad /R t
0 1 2 3 4 5 6 7 8 9 10
0
1
2
3
Rps /R t
0
1
2
3
Rad /R t
Bed Proximity Effect for Horizontal Well: Rshoulder = 10 ohm-m and R t = 100 ohm-m
Formation Resistivity—LWD
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzin Horizontal WellBed Proximity Effect—Open Hole
Rt-42
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Bed Proximity Effect for Horizontal Well: Rshoulder = 10 ohm-m, R t = 1 ohm-m
Bed Proximity Effect for Horizontal Well: Rshoulder = 10 ohm-m, R t = 100 ohm-m
0
1
2
3
Rps /R t
0 1 2 3 4 5 6 7 8 9 10
Distance to bed boundary (ft)
0
1
2
3
Rps /R t
0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10
0
1
2
3
Rad /R t
0 1 2 3 4 5 6 7 8 9 10
Distance to bed boundary (ft)
0
1
2
3
Rad /R t
General
General
Lithology—Wireline
Density and NGS* Natural Gamma Ray Spectrometry ToolMineral Identification—Open Hole
PurposeThis chart is a method for identifying the type of clay in the wellbore.
ExampleGiven: Environmentally corrected thorium concentration
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This chart is a method for identifying the type of clay in the wellbore.
The values of the photoelectric factor (Pe) from the Litho-Density*log and the concentration of potassium (K) from the NGS Natural
Gamma Ray Spectrometry tool are entered on the chart.
DescriptionEnter the upper chart with the values of Pe and K to determine the
point of intersection. On the lower chart, plotting Pe and the ratio
of thorium and potassium (Th/K) provides a similar mineral evalua-
tion. The intersection points are not unique but are in general areas
defined by a range of values.
Given: Environmentally corrected thorium concentration
(ThNGScorr) = 10.6 ppm, environmentally correctedpotassium concentration (KNGScorr) = 3.9%, and Pe = 3.2.
Find: Mineral concentration of the logged clay.
Answer: The intersection points from plotting values of Pe and K
on the upper chart and Pe and Th/K ratio = 10.6/3.9 = 2.7
on the lower chart suggest that the clay mineral is illite.
Lithology—Wireline
Density and NGS* Natural Gamma Ray Spectrometry ToolMineral Identification—Open Hole
Lith-1(former CP-18)
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Potassium concentration, K (%)
Photoelectricfactor, Pe
Glauconite
Chlorite Biotite
Illite
MuscoviteMontmorillonite
Kaolinite
0 2 4 6 8 10
10
8
6
4
2
0
10
Lithology—Wireline
NGS* Natural Gamma Ray Spectrometry ToolMineral Identification—Open Hole
Lith-2(former CP-19)
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0 1 2 3 4 5
Potassium (%)
25
20
15
10
5
0
Thorium(ppm)
M i x e d - l
a y e r c l a y
I l l i t e M i c a
s
G laucon i te
Potassium evaporites, ~30% feldspar
~30% glauconite
~70% illite
100% illite point
~40%mica
M o n t m
o r i l l o n i t e
C h l o r i t
e
Kaolinite
Possible 100% kaolinite,montmorillonite,illite “clay line”
T h / K
= 2 5
T h / K
= 1 2
T h / K =
3. 5
T h/ K = 2. 0
Th /K = 0.6
Th /K = 0.3Feldspar
H e a v y
t h o r i u
m - b e a r i n g
m i n
e r a l s
PurposeThis chart is used to determine the lithology and porosity of a forma-
ExampleGiven: Freshwater drilling mud, Pe = 3.0, and bulk density =
Lithology—Wireline
Platform Express* Three-Detector Lithology Density ToolPorosity and Lithology—Open Hole
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gy p y
tion. The porosity is used for the water saturation determination andthe lithology helps to determine the makeup of the logged formation.
DescriptionNote that this chart is designed for fresh water (fluid density
[ρf ] = 1.0 g/cm3) in the borehole. Chart Lith-4 is used for saltwater
(ρf = 1.1 g/cm3) formations.
Values of photoelectric factor (Pe) and bulk density (ρb) from the
Platform Express Three-Detector Lithology Density (TLD) tool are
entered into the chart. At the point of intersection, porosity and
lithology values can be determined.
g , , y
2.73 g/cm
3
.Freshwater drilling mud, Pe = 1.6, and bulk density =
2.24 g/cm3.
Find: Porosity and lithology.
Answer: For the first set of conditions, the formation is a
dolomite with 8% porosity.
The second set is for a quartz sandstone formation
with 30% porosity.
Lithology—Wireline
Platform Express* Three-Detector Lithology Density ToolPorosity and Lithology—Open Hole
Lith-3(former CP-16)
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1.9
2.0
2.1
2.2
2.3
2.4
2.5
Bulk density, ρb
(g/cm3)
4 0
3 0
2 0
1 0
4 0
3 0
2 0
4 0
3 0
2 0
1 0
0
Q u a r t z s a n d s t o n e
D o l o m i t e
C a l c i t e ( l i m e s t o n e )
S a
l t
Fresh Water (ρf = 1.0 g/cm3), Liquid-Filled Borehole
Lithology—Wireline
Platform Express* Three-Detector Lithology Density ToolPorosity and Lithology—Open Hole
Lith-4(former CP-17)
Salt Water (ρf = 1.1 g/cm3), Liquid-Filled Borehole
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1.9
2.0
2.1
2.2
2.3
2.4
2.5
2 6
Bulk density, ρb
(g/cm3)
4 0
3 0
2
0
1 0
4 0
3 0
2 0
Q u a r t z s a n d s t o n e
D o l o m i t e
4 0
3 0
2 0
1
0
C a l c i t e ( l i m
e s t o n e )
0 S a
l t
General
Lithology—Wireline, Drillpipe
Density ToolApparent Matrix Volumetric Photoelectric Factor—Open Hole
Lith-5(former CP-20)
Lithology—Wireline, LWD
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6 5 4 3 2 1 4 6 8 10 12 14
3.0
2.5
2.0
0
10
20
30
40
Photoelectric factor, Pe
Bulk density, ρb
(g/cm3)
Apparent totalporosity, φ ta (%)
Apparent matrix
volumetric photoelectric factor, Umaa
Fresh water (0 ppm), ρf = 1.0 g/cm3, Uf = 0.398Salt water (200,000 ppm), ρf = 1.11 g/cm3, Uf = 1.36
General
General
General
Lithology—Wireline, LWD
PurposeThis chart is used to identify the rock mineralogy through comparison
ExampleGiven: ρmaa = 2.74 g/cm3 (from Chart Lith-9 or Lith-10) and
Density ToolLithology Identification—Open Hole
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of the apparent matrix grain density (ρmaa ) and apparent matrix volu-metric photoelectric factor (Umaa ).
DescriptionThe values of ρmaa and Umaa are entered on the y- and x-axis, respec-
tively. The rock mineralogy is identified by the proximity of the point
of intersection of the two values to the labeled points on the plot.
The effect of gas, salt, etc., is to shift data points in the directions
shown by the arrows.
Umaa = 13 (from Chart Lith-5).Find: Matrix composition of the formation.
Answer: Enter the chart with ρmaa = 2.74 g/cm3 on the y-axis and
Umaa = 13 on the x-axis. The intersection point indicates
a matrix mixture of 20% dolomite and 80% calcite.
General
General
Lithology—Wireline, LWD
Density ToolLithology Identification—Open Hole
Lith-6(former CP-21)
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Apparent matrixgrain density,ρmaa (g/cm3)
2.2
2.3
2.4
2.5
2.6
2.7
2.8
Salt
K-feldspar
Quartz
Barite
Calcite
G a s d i r e c t i o n
% c al c i t e
e
% q u a r
2 0
608 0
40
6 0
4 0
8 0
4 0
2 0
PurposeThis chart is used to help identify mineral mixtures from sonic,
The lines on the chart are divided into numbered groups by poros-
ity range as follows:
Lithology—Wireline, LWD
Environmentally Corrected Neutron CurvesM–N Plot for Mineral Identification—Open Hole
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density, and neutron logs.DescriptionBecause M and N slope values are practically independent of porosity
except in gas zones, the porosity values they indicate can be corre-
lated with the mineralogy. (See Appendix E for the formulas to calcu-
late M and N from sonic, density, and neutron logs.)
Enter the chart with M on the y-axis and N on the x-axis. The
intersection point indicates the makeup of the formation. Points for
binary mixtures plot along a line connecting the two mineral points.
Ternary mixtures plot within the triangle defined by the three con-stituent minerals. The effect of gas, shaliness, secondary porosity,
etc., is to shift data points in the directions shown by the arrows.
1. φ = 0 (tight formation)2. φ = 0 to 12 p.u.
3. φ = 12 to 27 p.u.
4. φ = 27 to 40 p.u.
ExampleGiven: M = 0.79 and N = 0.51.
Find: Mineral composition of the formation.
Answer: The intersection of the M and N values indicates dolomite
in group 2, which has a porosity between 0 to 12 p.u.
Lithology—Wireline, LWD
Environmentally Corrected Neutron CurvesM–N Plot for Mineral Identification—Open Hole
Lith-7(former CP-8)
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1.1
1.0
0.9
0.8
0.7 Anhydrite
Dolomite
Gypsum
Calcite (limestone)
vma = 5943 m/s
= 19,500 ft/s
vma = 5486 m/s = 18,000 ft/s
Quartz sandstone
324 1
1 2 34
Secondaryporosity
G a s
o r
s a l t
M
Freshwater mudρf = 1.0 Mg/m3, t f = 620 µs/mρf = 1.0 g/cm3, t f = 189 µs/ft
Saltwater mudρf = 1.1 Mg/m3, t f = 607 µs/mρf = 1.1 g/cm3, t f = 185 µs/ft
General
General
General
Lithology—Wireline
PurposeThis chart is used to help identify mineral mixtures from APS
A l P i S d l
The lines on the chart are divided into numbered groups by poros-
ity range as follows:
Environmentally Corrected APS* CurvesM–N Plot for Mineral Identification—Open Hole
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Accelerator Porosity Sonde neutron logs.
DescriptionBecause M and N values are practically independent of porosity
except in gas zones, the porosity values they indicate can be corre-
lated with the mineralogy. (See Appendix E for the formulas to cal-
culate M and N from sonic, density, and neutron logs.)
Enter the chart with M on the y-axis and N on the x-axis. The
intersection point indicates the makeup of the formation. Points for
binary mixtures plot along a line connecting the two mineral points.
Ternary mixtures plot within the triangle defined by the three con-stituent minerals. The effect of gas, shaliness, secondary porosity,
etc., is to shift data points in the directions shown by the arrows.
1. φ = 0 (tight formation)2. φ = 0 to 12 p.u.
3. φ = 12 to 27 p.u.
4. φ = 27 to 40 p.u.
Because the dolomite spread is negligible, a single dolomite point
is plotted for each mud.
ExampleGiven: M = 0.80 and N = 0.55.
Find: Mineral composition of the formation.
Answer: Dolomite.
General
General
Lithology—Wireline
Environmentally Corrected APS* CurvesM–N Plot for Mineral Identification—Open Hole
Lith-8(former CP-8a)
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1.1
1.0
0.9
0.8
0.7 Anhydrite
Dolomite
Gypsum
Calcite (limestone)
vma = 5943 m/s
= 19,500 ft/s
vma = 5486 m/s = 18,000 ft/s
Quartz sandstone
12 3,4
Secondaryporosity
G a s
o r
s a l t
M
Freshwater mud
ρf = 1.0 Mg/m3, t f = 620 µs/m
ρf = 1.0 g/cm3, t f = 189 µs/ft
Saltwater mud
ρf = 1.1 Mg/m3, t f = 607 µs/m
ρf = 1.1 g/cm3, t f = 185 µs/ft
PurposeCharts Lith-9 (customary units) and Lith-10 (metric units) provide
l f th t t i i t l t it ti (t ) d
ExampleGiven: Apparent crossplot porosity from density-neutron = 20%,
ρ 2 4 / 3 t l t it f
Lithology—Wireline, LWD
Bulk Density or Interval Transit Time and Apparent Total PorosityApparent Matrix Parameters—Open Hole
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values of the apparent matrix internal transit time (tmaa ) and appar-
ent matrix grain density (ρmaa ) for the matrix identification (MID)
Charts Lith-11 and Lith-12. With these parameters the identification
of rock mineralogy or lithology through a comparison of neutron,
density, and sonic measurements is possible.
DescriptionDetermining the values of tmaa andρmaa to use in the MID Charts
Lith-11 and Lith-12 requires three steps.
First, apparent crossplot porosity is determined using the appro-
priate neutron-density and neutron-sonic crossplot charts in the“Porosity” section of this book. For data that plot above the sand-
stone curve on the charts, the apparent crossplot porosity is defined
by a vertical projection to the sandstone curve.
Second, enter Chart Lith-9 or Lith-10 with the interval transit
time (t) to intersect the previously determined apparent crossplot
porosity. This point defines tmaa .
Third, enter Chart Lith-9 or Lith-10 with the bulk density (ρb)
to again intersect the apparent crossplot porosity and define ρmaa .
The values determined from Charts Lith-9 and Lith-10 for tmaa andρmaa are cross plotted on the appropriate MID plot (Charts Lith-11
and Lith-12) to identify the rock mineralogy by its proximity to the
labeled points on the plot.
ρb = 2.4 g/cm3, apparent crossplot porosity from
neutron-sonic = 30%, and t = 82 µs/ft.
Find: ρmaa and tmaa .
Answer: ρmaa = 2.75 g/cm3 and tmaa = 46 µs/ft.
Lithology—Wireline, LWD
Bulk Density or Interval Transit Time and Apparent Total PorosityApparent Matrix Parameters—Open Hole
Lith-9(customary, former CP-14)
Fluid Density = 1 0 g/cm3
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130 120 110 100 90 80 70 60 50 40 303.0
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
130
120
110
100
90
80
70
60
50
Fluid Density = 1.0 g/cm3
Bulk density,ρb (g/cm3)
Interval transit time,
t (µs/ft)
Apparent matrix transit time, tmaa (µs/ft)
40
30
20
10
10
20
30
Apparentcrossplotporosity
D e n s i t y
- n e u
t r o n
N e u t r o n - s o
n i c
General
General
General
Fluid Density 1 0 g/cm3
Lithology—Wireline, LWD
Bulk Density or Interval Transit Time and Apparent Total PorosityApparent Matrix Parameters—Open Hole
Lith-10(metric, former CP-14m)
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350 325 300 275 250 225 200 175 150 125 1003.0
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
350
325
300
275
250
225
200
175
150
Fluid Density = 1.0 g/cm3
Bulk density,ρb (g/cm3)
Interval
transit time,
t (µs/m)
Apparent matrix transit time, tmaa (µs/m)
40
30
20
10
10
20
30
Apparentcrossplotporosity
D e n s i t y
- n e u
t r o n
N e u
t r o n - s o
n i c
General
PurposeCharts Lith-11 and Lith-12 are used to establish the type of mineral
predominant in the formation
General
Lithology—Wireline, LWD
Density ToolMatrix Identification (MID)—Open Hole
ρf Multiplier
1.00 1.00
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predominant in the formation.
DescriptionEnter the appropriate (customary or metric units) chart with
the values established from Charts Lith-9 or Lith-10 to identify the
predominant mineral in the formation. Salt points are defined for
two tools, the sidewall neutron porosity (SNP) and the CNL*
Compensated Neutron Log. The presence of secondary porosity
in the form of vugs or fractures displaces the data points parallel
to the apparent matrix internal transit time (tmaa ) axis. The presence
of gas displaces points to the right on the chart. Plotting some shalepoints to establish the shale trend lines helps in the identification
of shaliness. For fluid density (ρf ) other than 1.0 g/cm3 use the table
to determine the multiplier to correct the apparent total density
porosity before entering Chart Lith-11 or Lith-12.
ExampleGiven: ρmaa = 2.75 g/cm3, tmaa = 56 µs/ft (from Chart Lith-9),
and ρf = 1.0 g/cm3.
Find: The predominant mineral.
Answer: The formation consists of both dolomite and calcite, which indicates a dolomitized limestone. The formation
used in this example is from northwest Florida in the
Jay field. The vugs (secondary porosity) created by the
dolomitization process displace the data point parallel
to the dolomite and calcite points.
1.00 1.00
1.05 0.98
1.10 0.95
1.15 0.93
General
General
General
Lithology—Wireline, LWD
Density ToolMatrix Identification (MID)—Open Hole
Lith-11(customary, former CP-15)
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2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
ρmaa
(g/cm3)
Calcite
Dolomite
Quartz
G a s d i r
e c t i o
n
Salt(CNL* log)
Salt(SNP)
Lithology—Wireline, LWD
Density ToolMatrix Identification (MID)—Open Hole
Lith-12(metric, former CP-15m)
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2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
ρmaa
(g/cm3)
Calcite
Dolomite
Quartz
G a s d i r e
c t i o n
Salt(SNP)
Salt(CNL* log)
General
Porosity—Wireline, LWD
Sonic ToolPorosity Evaluation—Open Hole
PurposeThis chart is used to convert sonic log slowness time (∆t) values
into those for porosity (φ)
Example: Consolidated FormationGiven: ∆t = 76 µs/ft in a consolidated formation with
vma = 18 000 ft/s
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into those for porosity (φ).
DescriptionThere are two sets of curves on the chart. The blue set for matrix
velocity (v ma ) employs a weighted-average transform. The red set
is based on the empirical observation of lithology (see Reference
20). For both, the saturating fluid is assumed to be water with
a velocity (v f ) of 5,300 ft/s (1,615 m/s).
Enter the chart with the slowness time from the sonic log on the
x-axis. Move vertically to intersect the appropriate matrix velocity
or lithology curve and read the porosity value on the y-axis. For rockmixtures such as limy sandstones or cherty dolomites, intermediate
matrix lines may be interpolated.
To use the weighted-average transform for an unconsolidated sand,
a lack-of-compaction correction (Bcp) must be made. Enter the chart
with the slowness time and intersect the appropriate compaction
correction line to read the porosity on the y-axis. If the compaction
correction is not known, it can be determined by working backward
from a nearby clean water sand for which the porosity is known.
v ma = 18,000 ft/s.
Find: Porosity and the formation lithology (sandstone,
dolomite, or limestone).
Answer: 15% porosity and consolidated sandstone.
Example: Unconsolidated FormationGiven: Unconsolidated formation with ∆t = 100 µs/ft in
a nearby water sand with a porosity of 28%.
Find: Porosity of the formation for ∆t = 110 µs/ft.
Answer: Enter the chart with 100 µs/ft on the x-axis and move
vertically upward to intersect 28-p.u. porosity. This
intersection point indicates the correction factor curve
of 1.2. Use the 1.2 correction value to find the porosity for
the other slowness time. The porosity of an unconsoli-
dated formation with ∆t = 110 µs/ft is 34 p.u.
Lithology vma (ft/s) ∆ tma (µs/ft) vma (m/s) ∆ tma (µs/m)
Sandstone 18,000–19,500 55.5–51.3 5,486–5,944 182–168
Limestone 21,000–23,000 47.6–43.5 6,400–7,010 156–143
Dolomite 23,000–26,000 43.5–38.5 7,010–7,925 143–126
Porosity—Wireline, LWD
Sonic ToolPorosity Evaluation—Open Hole
Por-1(customary, former Por-3)
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vf = 5,300 ft/s
50
40
30
20
50
40
30
20
Porosity,φ (p.u.)
Porosity,φ (p.u.)
Time average
Field observation
1.1
1.2
1.3
1.4
1.5
1.6
D o l o m
i t e
2 6 , 0 0 0
00
vma(ft/s)
Bcp
23 , 0 0 0
C a l c
i t e ( l i m
e s t o n e )
Q u a r t z s a n d s t o n e
Porosity—Wireline, LWD
Sonic ToolPorosity Evaluation—Open Hole
Por-2(metric, former Por-3m)
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vf = 1,615 m/s
50
40
30
20
50
40
30
20
Porosity,φ (p.u.)
Porosity,φ (p.u.)
1.1
1.2
1.3
1.4
1.5
1.6
D o l o
m i t e
8 , 0 0 0
vma(m/s)
Bcp
Time average
Field observation
00 0
C a l c i t e
Q u a r t z s a n d
s t o n e
D o l o m
i t e
C a l c i t e
tz s a n d s t o
n e
e m e n t
e d q u a r t z
s a n d
s t o n
e
Por-3(former Por-5)
Density ToolPorosity Determination—Open Hole
Porosity—Wireline, LWD
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1.0 0.9 0.8
1.1
1.2
Porosity,φ (p.u.)
ρ m a =
2 . 8 7
( d o l o m
i t e )
ρ m a = 2
. 7 1
( c a l c i t e )
ρ m a =
2 . 6 5
( q u a r t z
s a n d
s t o n
e )
ρ m
a =
2 . 8 3
ρ m a =
2 . 6 8
ρma – ρb
ρma – ρf
φ =
ρf (g/cm3)
40
30
20
10
PurposeThis chart is used for the apparent limestone porosity recorded by the
APS Accelerator Porosity Sonde or sidewall neutron porosity (SNP)
The HPLC curve is the high-resolution version of the APLC curve.
The same corrections apply.
APS* Near-to-Array (APLC) and Near-to-Far (FPLC) LogsEpithermal Neutron Porosity Equivalence—Open Hole
Porosity—Wireline
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y p y ( )
tool to provide the equivalent porosity in sandstone or dolomite for-
mations. It can also be used to obtain the apparent limestone poros-
ity (used for the various crossplot porosity charts) for a log recorded
in sandstone or dolomite porosity units.
DescriptionEnter the x-axis with the corrected near-to-array apparent limestone
porosity (APLC) or near-to-far apparent limestone porosity (FPLC)
and move vertically to the appropriate lithology curve. Then read the
equivalent porosity on the y-axis. For APS porosity recorded in sand-stone or dolomite porosity units enter that value on the y-axis and
move horizontally to the recorded lithology curve. Then read the
apparent limestone neutron porosity for that point on the x-axis.
The APLC is the epithermal short-spacing apparent limestone
neutron porosity from the near-to-array detectors. The log is auto-
matically corrected for standoff during acquisition. Because it is
epithermal this measurement does not need environmental correc-
tions for temperature or chlorine effect. However, corrections for
mud weight and actual borehole size should be applied (see ChartNeu-10). The short spacing means that the effect of density and
therefore the lithology on this curve is minimal.
The FPLC is the epithermal long-spacing apparent limestone neu-
tron porosity acquired from the near-to-far detectors. Because it is
epithermal this measurement does not need environmental correc-
tions for temperature or chlorine effect. However, corrections for
mud weight and actual borehole size should be applied (see Chart
Neu-10). The long spacing means that the density and therefore
lithology effect on this curve is pronounced, as seen on Charts Por-13and Por 14
Example: Equivalent Porosity
Given: APLC = 25 p.u. and FPLC = 25 p.u.
Find: Porosity for sandstone and for dolomite.
Answer: Sandstone porosity from APLC = 28.5 p.u. and sandstone
porosity from FPLC = 30 p.u.
Dolomite porosity = 24 and 20 p.u., respectively.
Example: Apparent PorosityGiven: Clean sandstone porosity = 20 p.u.
Find: Apparent limestone neutron porosity. Answer: Enter the y-axis at 20 p.u. and move horizontally to
the quartz sandstone matrix curves. Move vertically
from the points of intersection to the x-axis and read
the apparent limestone neutron porosity values.
APLC = 16.8 p.u. and FPLC = 14.5 p.u.
Resolution Short Spacing Long Spacing
Normal APLCFPLCEpithermal neutron porosity (ENPI)†
Enhanced HPLCHFLCHNPI†
† Not formation-salinity corrected.
Porosity—Wireline
APS* Near-to-Array (APLC) and Near-to-Far (FPLC) LogsEpithermal Neutron Porosity Equivalence—Open Hole Por-4
(former Por-13a)
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40
30
20
10
0
True porosityfor indicated
matrix material,φ (p.u.)
C a l c i t e
( l i m e s t o
n e )
D o l o m
i t e
APLC
FPLC
SNP
Q u a r t z
s a n d
s t o n
e
Thermal Neutron ToolPorosity Equivalence—Open Hole
General
Porosity—Wireline
Por-5(former Por-13b)
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40
30
20
10
00 10 20 30 40
True porosityfor indicated
matrix material,φ (p.u.)
Q u a
r t z
s a n d
s t o n e
C a
l c i t e
( l i m e s t o
n e )
D o l o m
i t e
Formation salinity
TNPH
NPHI
0 ppm
250,000 ppm
Porosity—Wireline
Thermal Neutron Tool—CNT-D and CNT-S 21 ⁄ 2-in. ToolsPorosity Equivalence—Open Hole
Por-6
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40
30
20
10
S a n d
s t o n
e
D o l o
m i t e
L i m
e s t o
n e
True porosityfor indicated
matrix material,φ (p.u.)
General
Porosity—LWD
adnVISION475* 4.75-in. Azimuthal Density Neutron ToolPorosity Equivalence—Open Hole
Por-7
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–5 0 5 10 15 20 25 30 35 40
40
35
30
25
20
15
10
5
0
Corrected apparent limestone neutron porosity, φADNcor (p.u.)
True porosityfor indicated
matrix material,φ (p.u.)
Q u a r t z
s a n d
s t o n e
C a l c i
t e ( l i m
e s t o n e )
D o l o m
i t e
Porosity—LWD
adnVISION675* 6.75-in. Azimuthal Density Neutron ToolPorosity Equivalence—Open Hole
Por-8
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–5 0 5 10 15 20 25 30 35 40
40
35
30
25
20
15
10
5
0
Corrected apparent limestone neutron porosity, φADNcor (p.u.)
True porosityfor indicated
matrix material,φ (p.u.)
Q u a r t z s a n d s t o n e
C a l c i t e ( l i m e s t o n e )
D o l o m
i t e
Porosity—LWD
adnVISION825* 8.25-in. Azimuthal Density Neutron ToolPorosity Equivalence—Open Hole
Por-9
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–5 0 5 10 15 20 25 30 35 40
40
35
30
25
20
15
10
5
0
Corrected apparent limestone neutron porosity,φADNcor (p.u.)
True porosity(p.u.)
S a n d s t o n e
L i m e s t o n e
D o l o m i t e
Porosity—LWD
EcoScope* 6.75-in. Integrated LWD Tool, BPHI PorosityPorosity Equivalence—Open Hole
Por-10
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–5 0 5 10 15 20 25 30 35 40
40
35
30
25
20
15
10
5
0
C t d t li t BPHI it ( )
True porosityfor indicated
matrix material,φ (p.u.)
S a n d s t o n e
L i m e s t o n e
D o l o m
i t e
Porosity—LWD
EcoScope* 6.75-in. Integrated LWD Tool, TNPH PorosityPorosity Equivalence—Open Hole
Por-10a
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–5 0 5 10 15 20 25 30 35 40
40
35
30
25
20
15
10
5
0
C d li TNPH i ( )
True porosityfor indicated
matrix material,φ (p.u.)
S a n d
s t o n
e
L i m e s t o n e
D o l o m
i t e
Porosity—Wireline
CNL* Compensated Neutron Log and Litho-Density* Tool(fresh water in invaded zone)Porosity and Lithology—Open Hole
PurposeThis chart is used with the bulk density and apparent limestone
porosity from the CNL Compensated Neutron Log and Litho-Density
t l ti l t i t th lith l d d t i th
ExampleGiven: Corrected apparent neutron limestone porosity =
16.5 p.u. and bulk density = 2.38 g/cm3.
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tools, respectively, to approximate the lithology and determine thecrossplot porosity.
DescriptionEnter the chart with the environmentally corrected apparent neu-
tron limestone porosity on the x-axis and bulk density on the y-axis.
The intersection of the two values describes the crossplot porosity
and lithology.
If the point is on a lithology curve, that indicates that the forma-
tion is primarily that lithology. If the point is between the lithology curves, then the formation is a mixture of those lithologies. The posi-
tion of the point in relation to the two lithology curves as composi-
tion endpoints indicates the mineral percentages of the formation.
The porosity for a point between lithology curves is determined
by scaling the crossplot porosity by connecting similar numbers on
the two lithology curves (e.g., 20 on the quartz sandstone curve to
20 on the limestone curve). The scale line closest to the point repre-
sents the crossplot porosity.
Chart Por-12 is used for the same purpose as this chart for salt- water-invaded zones.
Find: Crossplot porosity and lithology.
Answer: Crossplot porosity = 18 p.u. The lithology is approxi-
mately 40% quartz and 60% limestone.
General
Porosity—Wireline
CNL* Compensated Neutron Log and Litho-Density* Tool(fresh water in invaded zone)Porosity and Lithology—Open Hole
Por-11(former CP-1e)
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1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
Bulkdensity,ρb (g/cm3)
Densityporosity,φD (p.u.)
(ρma = 2.71 g/cm3,ρf = 1.0 g/cm3)
45
40
35
30
25
20
15
10
5
0
SulfurSalt
A p p r o x i m a t e g a s c o r r e c t i o n P o r o s i t y
C a l c i t e ( l i m e s t o n e )
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
4 5
Q u a r t z s a n d s t o n e
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
D o l o m i t e
1 0
1 5
2 0
2 5
3 0
3 5
Liquid-Filled Borehole (ρf = 1.000 g/cm3 and Cf = 0 ppm)
General
Porosity—Wireline
CNL* Compensated Neutron Log and Litho-Density* Tool(salt water in invaded zone)Porosity and Lithology—Open Hole
Por-12(former CP-11)
1 9
Liquid-filled borehole (ρf = 1.190 g/cm3 and Cf = 250,000 ppm)
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1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
Bulkdensity,ρb (g/cm3)
Densityporosity,φD (p.u.)
(ρma = 2.71 g/cm3,
ρf = 1.19 g/cm3
)
45
40
35
30
25
20
15
10
5
0
–5
–10
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
4 5
0
5
1 0
1 5
2 0
2 5
3 0
3 5
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
4 5
A p p r o x i m a t e g a s c o r r e c t i o n
P o r o s i t y
Q u a r t z s a n d s t o n e
C a l c i
t e ( l i m
e s t o n
e )
SulfurSalt
D o l o m
i t e
General
Porosity—Wireline
APS* and Litho-Density* ToolsPorosity and Lithology—Open Hole
Por-13(former CP-1g)
Liquid Filled Borehole (ρ 1 000 g/cm3 and C 0 ppm)
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Liquid-Filled Borehole (ρf = 1.000 g/cm3 and Cf = 0 ppm)
Bulk density,ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
APLC
FPLC
e
D o l o
m i t e
C a l c i
t e ( l i m
e s t o n
e )
Q u a r t z s a
n d s t o
n e
P o r o s i t y
A p p r o x i m a t e g a s c o r r e c t i o n
0
5
5
1 0
1 0
1 5
1 5
2 0
2 0
2 5
2 5
3 5
3 5 3 0
3 0
4 0
4 0
4 5
0
5
4 0
3 5
3 0
2 5
2 0
1 5
1 0
0
3 5
3 0
2 5
2 0
1 5 1 5
1 0
5
0
0
1 0
2 0
3 0
3 5
4 0
5
2 5
General
Porosity—Wireline
APS* and Litho-Density* Tools (saltwater formation)Porosity and Lithology—Open Hole
Por-14(former CP-1h)
Liquid Filled Borehole (ρf 1 190 g/cm3 and Cf 250 000 ppm)
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Liquid-Filled Borehole (ρf = 1.190 g/cm3 and Cf = 250,000 ppm)
Bulk density,ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9ite
P o r o s
i t y
A p p r o x i m a t e g a s c o r r e c t i o n
0
0
5
5
1 0
1 0
1 5
1 5
2 0
2 0
2 5
2 5
3 5
3 5 3 0
3 0
4 0
4 0
4 5
0
5
4 0
3 5
3 0
2 5
2 0
1 5
1 0
0
4 0
3 5
3 0
2 5
2 0
1 5
1 0
5
0
4 5 4 5
APLC
FPLC
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
Q u a r t z
s a n d
s t o n e
D o l o m
i t e C a l c i
t e ( l i m
e s t o n
e )
General
Porosity—LWD
adnVISION475* 4.75-in. Azimuthal Density Neutron ToolPorosity and Lithology—Open Hole
Por-15
Fresh Water Liquid Filled Borehole (ρf 1 0 g/cm3)
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Bulk density,ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
Salt
Fresh Water, Liquid-Filled Borehole (ρf = 1.0 g/cm3)
D o l o m i t e
C a l c i
t e ( l i m
e s t o n e )
Q u a r t z s a n d s t o n e
P o r o s i t y
0
0
5
1 0
1 0
1 5
1 5
2 0
2 0
2 5
2 5
3 5
3 5 3 0
3 0
4 0
4 0
4 0
3 5
3 0
2 5
2 0
1 5
1 0
5
0 5
General
Porosity—LWD
adnVISION675* 6.75-in. Azimuthal Density Neutron ToolPorosity and Lithology—Open Hole
Por-16
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Bulk density,
ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
Fresh Water, Liquid-Filled Borehole (ρf = 1.0 g/cm3)
D o l o
m i t e
C a l c i t e ( l i m e s t o n e )
Q u a r t z s a n d s t o n e
0
0
1 0
1 0
1 5
2 0
2 5
5
5
5
1 0
1 5
2 0
0
2 5
3 5
3 0
1 5
2 0
2 5
3 5
3 0
3 0
3 5
4 0
4 0
P o r o s i t y
General
Porosity—LWD
adnVISION825* 8.25-in. Azimuthal Density Neutron ToolPorosity and Lithology—Open Hole
Por-17
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Bulk density,
ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
Fresh Water, Liquid-Filled Borehole (ρf = 1.0 g/cm3)
C a l c i t e ( l i m e s t o n e )
Q u a r t z s a n d s t o n e
0
1 0
5
D o l o m i t e
5
1 0
1 5
2 0
0
2 5
3 5
3 0
1 5
2 0
2 5
3 5
3 0
4 0
0
1 0
1 5
2 0
5
3 0
3 5
4 0
2 5
P o r o
s i t y 4 0
Porosity—LWD
EcoScope* 6.75-in. Integrated LWD ToolPorosity and Lithology—Open Hole
Por-18
1 9
Fresh Water, Liquid-Filled Borehole (ρf = 1.0 g/cm3)
5
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Bulk density,ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
Salt
0
1 0
1 5
2 0
2 5
3 5
3 0
4 0
5
0
1 0
1 5
2 0
2 5
3 5
3 0
4 0
4 5
5
D o l o m i t e
L i m e s
t o n e
S a n d s t o n e
0
1 0
1 5
2 0
2 5
3 5
3 0
4 0
5
Porosity—LWD
EcoScope* 6.75-in. Integrated LWD ToolPorosity and Lithology—Open Hole
Por-19
1 9
Fresh Water, Liquid-Filled Borehole (ρf = 1.0 g/cm3)
45
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Bulk density,ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
0
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
4 5
Salt
D o l o m i t e
L i m e s
t o n e
S a n d s t o n e
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
General
Porosity—Wireline
Sonic and Thermal Neutron CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded
PurposeThis chart is used to determine crossplot porosity and an approxi-
mation of lithology for sonic and thermal neutron logs in freshwater
drilling fluid
ExampleGiven: Thermal neutron apparent limestone porosity = 20 p.u.
and sonic slowness time = 89 µs/ft in freshwater
drilling fluid
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drilling fluid.
DescriptionEnter the corrected neutron porosity (apparent limestone porosity)
on the x-axis and the sonic slowness time (∆t) on the y-axis to find
their intersection point, which describes the crossplot porosity and
lithology composition of the formation. Two sets of curves are drawn
on the chart. The blue set of curves represents the crossplot porosity
values using the sonic time-average algorithm. The red set of curves
represents the field observation algorithm.
drilling fluid.
Find: Crossplot porosity and lithology.
Answer: Enter the neutron porosity on the x-axis and the sonic
slowness time on the y-axis. The intersection point is at
about 25 p.u. on the field observation line and 24.5 p.u.
on the time-average line. The matrix is quartz sandstone.
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General
General
Porosity—Wireline, LWD
Density and Sonic CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded
PurposeThis chart is used to determine porosity and lithology for sonic and
density logs in freshwater-invaded zones.
D i ti
ExampleGiven: Bulk density = 2.3 g/cm3 and sonic slowness
time = 82 µs/ft.
Find: Crossplot porosity and lithology
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DescriptionEnter the chart with the bulk density on the y-axis and sonic slow-
ness time on the x-axis. The point of intersection indicates the type
of formation and its porosity.
Find: Crossplot porosity and lithology.
Answer: Limestone with a crossplot porosity = 24 p.u.
General
Porosity—Wireline, LWD
Density and Sonic CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded
Por-22(customary, former CP-7)
1.8
tf = 189 µs/ft and ρf = 1.0 g/cm3
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1.9
2.0
2.1
2.2
2.3
2.4
2.5
Bulk density,ρb (g/cm3)
Gypsum
Trona
Salt
Sylvite
Sulfur
1 010
2 0
3 0
4 0
4 0 4 0 4 0
4 0
3 0 3 0
2 0
P
o r o s i t y
Time average
Field observation
3 0
3 0 3 0
2 0 2 0
2 0
1 0
2 00
General
General
Porosity—Wireline, LWD
Density and Sonic CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded
Por-23(metric, former CP-7m)
1.8
tf = 620 µs/m and ρf = 1.0 g/cm3
Time average
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1.9
2.0
2.1
2.2
2.3
2.4
2.5
Bulk density,ρb (g/cm3)
Gypsum
Trona
Salt
Sylvite
Sulfur
1 0
1 0 2 0
2 0
2 0 3 0
4 0
3 0
4 0 4 0
4 0
3 0 3 0
2 0
P o r o s i t
y
3 0
1 0
g
Field observation
3 0
1 0
2 0
2 0
4 0
General
Porosity—Wireline, LWD
Density and Neutron ToolPorosity Identification—Gas-Bearing Formation
PurposeThis chart is used to determine the porosity and average water satu-
ration in the flushed zone (S xo) for freshwater invasion and gas com-
position of C1.1H4.2 (natural gas).
ExampleGiven: φD = 25 p.u. and φN = 10 p.u. in a low-pressure, shallow
(4,000-ft) reservoir.
Find: Porosity and Sxo.
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p ( g )
DescriptionEnter the chart with the neutron- and density-derived porosity values
(φN and φD, respectively). On the basis of the table, use the blue curves
for shallow reservoirs and the red curves for deep reservoirs.
y xo
Answer: Enter the chart at 25 p.u. on the y-axis and 10 p.u. on the
x-axis. The point of intersection identifies (on the blue
curves for a shallow reservoir) φ = 20 p.u. and S xo = 62%.
Depth Pressure Temperature ρw (g/cm3) IHw ρg (g/cm3) IHg
Shallow reservoir ~2,000 psi [~14,000 kPa] ~120°F [~50°C] 1.00 1.00 0 0Deep reservoir ~7,000 psi [~48,000 kPa] ~240°F [~120°C] 1.00 1.00 0.25 0.54
ρw = density of water, ρg = density of gas, IHw = hydrogen index of water, and IHg = hydrogen index of gas
General
General
General
Porosity—Wireline, LWD
Density and Neutron ToolPorosity Identification—Gas-Bearing Formation
Por-24(former CP-5)
50
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Density-derived porosity,φD (p.u.)
50
40
30
20
Sxo
Sxo
15
20
Porosity
30
80
35
025
40
15
10
20
100
30
25
60
40
60
20
100
80
35
40
20
0
10
General
PurposeThis chart is used to determine the porosity and average water satu-
ration in the flushed zone (S xo) for freshwater invasion and gas com-
position of CH4 (methane).
ExampleGiven: φD = 15 p.u. and APS φN = 8 p.u. in a normally pressured
deep (14,000-ft) reservoir.
Find: Porosity and S xo.
Porosity—Wireline
Density and APS* Epithermal Neutron ToolPorosity Identification—Gas-Bearing Formation
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( )
DescriptionEnter the chart with the APS Accelerator Porosity Sonde neutron- and
density-derived porosity values (φN and φD, respectively). On the basis
of the table, use the blue curves for shallow reservoirs and the red
curves for deep reservoirs.
y
Answer: φ= 11 p.u. and S xo = 39%.
Depth Pressure Temperature ρw IHw ρg IHg
Shallow reservoir ~2,000 psi [~14,000 kPa] ~120°F [~50°C] 1.00 1.00 0.10 0.23
Deep reservoir ~7,000 psi [~48,000 kPa] ~240°F [~120°C] 1.00 1.00 0.25 0.54
ρw = density of water, ρg = density of gas, IHw = hydrogen index of water, and IHg = hydrogen index of gas
General
General
General
Porosity—Wireline
Density and APS* Epithermal Neutron ToolPorosity Identification—Gas-Bearing Formation
Por-25(former CP-5a)
50
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Density-derived porosity,φD (p.u.)
50
40
30
20
1515
2020
40
3030
40
80
35
35
25
25
40
20
0
100Sxo
Sxo
80
100
20
0
60
40
60
Porosity
1010
General
PurposeThis nomograph is used to estimate porosity in hydrocarbon-bearing
formations by using density, neutron, and resistivity in the flushed
zone (R xo) logs. The density and neutron logs must be corrected fori t l ff t d lith l b f t t th h
ExampleGiven: Corrected CNL apparent neutron porosity = 12 p.u.,
corrected apparent density porosity = 38 p.u., and
Shr = 50%.
General
General
Porosity—Wireline
Density, Neutron, and Rxo LogsPorosity Identification in Hydrocarbon-Bearing Formation—Open Hole
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environmental effects and lithology before entry to the nomograph.
The chart includes an approximate correction for excavation effect,
but if hydrocarbon density (ρh) is <0.25 g/cm3 (gas), the chart may
not be accurate in some extreme cases:
very high values of porosity (>35 p.u.) coupled with medium
to high values of hydrocarbon saturation (Shr) Shr = 100% for medium to high values of porosity.
DescriptionConnect the apparent neutron porosity value on the appropriate
neutron porosity scale (CNL* Compensated Neutron Log or sidewall
neutron porosity [SNP] log) with the corrected apparent density
porosity on the density scale with a straight line. The intersection
point on the φ1 scale indicates the value of φ1.
Draw a line from the φ1 value to the origin (lower right corner)
of the chart for ∆φ versus Shr.
Enter the chart with Shr from (Shr = 1 – S xo) and move vertically
upward to determine the porosity correction factor (∆φ) at the inter-
section with the line from the φ1 scale.
This correction factor algebraically added to the porosity φ1 gives
the corrected porosity.
Find: Hydrocarbon-corrected porosity.
Answer: Enter the 12-p.u. φcor value on the CNL scale. A line from
this value to 38 p.u. on the φDcor scale intersects the φ1
scale at 32.2 p.u. The intersection of a line from this
value to the graph origin and Shr = 50% is ∆φ = –1.6 p.u.
Hydrocarbon-corrected porosity: 32.2 – 1.6 = 30.6 p.u.
General
General
General
Porosity—Wireline
Density, Neutron, and Rxo LogsPorosity Identification in Hydrocarbon-Bearing Formation—Open Hole
Por-26(former CP-9)
φDcorφ1φcor
(SNP)
φcor
(CNL*)
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–5
–4
50
40
30
20
50
40
30
20
50
40
30
20
50
40
30
20
(p.u.)
General
Porosity—Wireline
Hydrocarbon Density EstimationPor-27
(former CP-10)
1.0
0.8
ρh
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1.0
0.8
0.6
φCNLcor
φ
0.8
ρh
0.7
0.6
0.8
0.6
0.4
0.2
0 0 20 40 60 80 100
0.7
0.6
0.5
0.4
0.3
0.20.1
0
Shr (%)
φSNPcor
φDcor
General
Saturation—Wireline, LWD
Porosity Versus Formation Resistivity FactorOpen Hole
SatOH-1(former Por-1)
2.5 5 10 20 50 100 200 500 1,000 2,000 5,000 10,00050
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40
30
25
20
15
10987
6
5
4
3
2
1
Porosity,φ (p.u.)
1.4
1.6
1.82.0
2.2
2.5
2.8
FR =0.81
φ2
FR =1φ2
FR =0.62φ2.15
FR =1
φmm
Fractures
Vugs orspherical pores
Saturation—Wireline, LWD
Spherical and Fracture PorosityOpen Hole
SatOH-2(former Por-1a)
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0.5 0.8 1 2 4 6 8 10 20 30 40 50
Porosity, φ (p.u.)
3.0
2.5
2.0
1.5
1.0
Cementationexponent, m
Fractures
φ f r = 0
. 1
0. 2
2. 5
1 0 . 0
0. 5
1. 0
1. 5 2. 0
5. 0
φiso = 0.5
1.0
1.5
2.55.0
7.510.0
12.5
2.0 Isolatedpores
Saturation—Wireline, LWD
Saturation DeterminationOpen Hole
Purpose
This nomograph is used to solve the Archie water saturation
equation:
Description
If Ro is known, a straight line from the known Ro value through the
measured Rt value indicates the value of S w . If Ro is unknown, it may
be determined by connecting R w with FR or porosity (φ).R F R
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where
S w = water saturation
Ro = resistivity of clean-water formation
Rt = true resistivity of the formation
FR = formation resistivity factorR w = formation water resistivity.
It should be used in clean (nonshaly) formations only.
ExampleGiven: R w = 0.05 ohm-m at formation temperature, φ = 20 p.u.
(FR = 25), and Rt = 10 ohm-m.
Find: Water saturation.
Answer: Enter the nomograph on the R w scale at R w = 0.05 ohm-m.
Draw a straight line from 0.05 through the porosity scale
at 20 p.u. to intersect the Ro scale.
From the intersection point of Ro = 1, draw a straight line
through Rt = 10 ohm-m to intersect the S w scale.
S w = 31.5%.
SR
R
F R
R w o
t
R w
t
= = ,
Saturation—Wireline, LWD
Saturation DeterminationOpen Hole
SatOH-3(former Sw-1)
Ro
(ohm-m)R t
(ohm-m)
Sw
(%)
5
Clean Formations, m = 2
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Rw
(ohm-m)
( ) ( )
φ(%)
FR
2,000
1,000800600
400300200
1008060504030
20
108654
2.5
3
4
567
89
10
15
20
25
3035404550
FR =1
φ2.0
m = 2.0
0.01
0.02
0.03
0.04
0.05
0.060.070.080.090.1
0.2
0.3
0.4
0.5
0.60.7
6
7
8
9
10
111213141516
18
20
25
30
40
50
60
10,0008,0006,0005,0004,0003,000
2,000
1,000
800600500400300
200
1008060504030
20
1086543
2
1.00.8
30
20181614
1210
987
6
5
4
3
21.8
1.61.41.2
1.00.90.80.70.6
0.5
0.4
0.3
Saturation—Wireline, LWD
Saturation DeterminationOpen Hole
Purpose
This chart is used to determine water saturation (S w ) in shaly or
clean formations when knowledge of the porosity is unavailable. It
may also be used to verify the water saturation determination fromanother interpretation method The large chart assumes that the
Example
Given: R xo = 12 ohm-m, Rt = 2 ohm-m, Rmf /R w = 20, and
Sor = 20%.
Find: S w (after correction for ROS).
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another interpretation method. The large chart assumes that the
mud filtrate saturation is
The small chart provides an S xo correction when S xo is known.
However, water activity correction is not provided for the SP portion
of the chart (see Chart SP-2).
Description
Clean Sands Enter the large chart with the ratio of the resistivity of the flushed
zone to the true formation resistivity (R xo /Rt) on the y-axis and the
ratio of the resistivity of the mud filtrate to the resistivity of the for-
mation water (Rmf /R w ) on the x-axis to find the water saturation at
average residual oil saturation (S wa ). If Rmf /R w is unknown, the chart
may be entered with the spontaneous potential (SP) value and the
formation temperature. If S xo is known, move diagonally upward,parallel to the constant-S wa curves, to the right edge of the chart.
Then, move horizontally to the known S xo (or residual oil saturation
[ROS], Sor) value to obtain the corrected value of S w .
Answer: Enter the large chart at R xo /Rt = 12/2 = 6 on the
y-axis and Rmf /R w = 20 on the x-axis. From the point of
intersection (labeled A), move diagonally to the right to
intersect the chart edge and directly across to enter the
small chart and intersect Sor = 20%.
S w = 43%.
DescriptionShaly Sands
Enter the chart with R xo /Rt and the SP in the shaly sand (EPSP). The
point of intersection gives the S wa value. Draw a line from the chart’s
origin (the small circle located at R xo /Rt = Rmf /Rm = 1) through this
point to intersect with the value of static spontaneous potential (ESSP)
to obtain a value of R xo /Rt corrected for shaliness. This value of R xo /Rt
versus Rmf /R w is plotted to find S w if Rmf /R w is unknown because the
point defined by R xo /Rt and ESSP is a reasonable approximation of S w .
The small chart to the right can be used to further refine S w if Sor isknown.
ExampleGiven: R xo /Rt = 2.8, Rmf /R w = 25, EPSP = –75 mV, ESSP = –120 mV,
and electrochemical SP coefficient (K c) = 80 (formation
temperature = 150ºF).
Find: S w and corrected value for Sor = 10%.
Answer: Enter the large chart at R xo /Rt = 2.8 and the intersection
of EPSP = –75 mV at K c = 80 from the chart below. A linef h i i h h h i i i (l b l d B)
S S XO W = 5 .
Saturation—Wireline, LWD
Saturation DeterminationOpen Hole
SatOH-4(former Sw-2)
0 10 20 30 40Rmf /Rw
Sor (%)
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50
40
30
20
10
8
6
5
4
3
2
1
0.8
0.6
0.80.6 1.0 1.5 2.52 3 4 5 6 8 10 15 20 25 30 40 50 60
1.0 0.9 0.8 0.7 0.6
80
70
60
50
40
30
25
20
15
10
6 0
5 0
4 0
2 5
3 0
2 0
1 5
Rxo
R t
S w ( % )
A
B
C
D
%
2 5 %
3 0 %
4 0 %
5 0 %
6 0 %
7 0 %
S w a = 1 0 0 %
EPSP = –Kc log – 2Kc logRxo
R t
Sxo
Sw
Sxo = S w
5
Sxo = Sw
5
Saturation—Wireline, LWD
Graphical Determination of Sw from Swt and Swb
Open Hole SatOH-5
(former Sw-14)
100
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90
80
70
60
50
40
30
20
10
Swt (%)
Swb
70%
60%
50%
40%
30%
20%
10%
0
Saturation—Wireline, LWD
Porosity and Gas Saturation in Empty HoleOpen Hole
SatOH-6(former Sw-11)
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Porosity, φ (p.u.)
Density and Hydrogen Index of Gas Assumed ZeroUse if noshale present
Use if nooil present
100 10 000
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2.65
2.70
2.75
2 80
2
4
6
8
10
1214
16
18
20
22
24
26
28
30
Neutronporosity
index(corrected
for lithology)
Matrix density,ρma (g/cm3)
2.6 2.5 2.4 2.3 2.2 2.1 2.0 1.9 1.8SandstoneLimy sandstoneLimestone
100
90
80
70
60
50
40
30
20
10
0
G a s s a t u
r a t i o
n , S g ( %
)
10,0004,0002,0001,000
400300
200150
100
70
6050
40
30
20
151413
1211
R t
Rw
Saturation—Wireline
EPT* Propagation TimeOpen Hole
SatOH-7(former Sxo-1)
7 8 9 10
tpma (ns/m)
21
7 8 9 10
tpma (ns/m)
Sxo
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21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
Sxo
(%)
5 0 4 5
4 0 3 5
3 0 2 5
2 0
1 5
1 0
5
tpl (ns/m)
10.9
100
90
80
70
60
50
40
30
20
10
0
53%
t p w ( n s /
m )
2 1
2 5
3 0
3 5
4 0
5 0 6 0
7 0 8 0 9 0
G a s O
i l
F o r m
a t i o
n p o
r o s i t y
( % )
Saturation—Wireline
EPT* AttenuationOpen Hole
SatOH-8(former Sxo-2)
Sxo
(%)
5
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Aw
(dB/m)
AEPTcor
(dB/m)
φ(p.u.)
6,000
5,000
4,000
3,000
2,000
1,000900800
700600
500
400
300
200
2
3
4
6
8
1
10
20
30
40
60
80100
200
300
6
7
8
910
20
30
40
50
60
70
80
90
100
1
2
3
45
10
15
20
30
40
Purpose
This chart is used to determine water saturation (S w ) from capture
cross section, or sigma (Σ), measurements from the TDT* Thermal
Decay Time pulsed neutron log.
D i ti
Procedure
Shaly Formation
The S w determination in a shaly formation requires additional infor-
mation: sigma shale (Σsh) read from the TDT log in adjacent shale,Vsh from porosity-log crossplot or gamma ray shale porosity (φsh) read
Saturation—Wireline
Capture Cross Section ToolCased Hole
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DescriptionThis chart uses sigma water (Σ w ), matrix capture cross section (Σma ),
and porosity (φ) to determine water saturation in clean formations.
The chart may be used in shaly formations if sigma shale (Σsh), the
volume fraction of shale in the formation (V sh), and the porosity cor-
rected for shale are known.
Thermal decay time (t and tsh in shale) is also shown on some
of the chart scales because it is related to Σ.Procedure
Clean Formation
The S w determination for a clean formation requires values known
for Σma (based on lithology), φ, Σ w from the NaCl salinity (see Chart
Gen-12 or Gen-13), and sigma hydrocarbon (Σh) (see Chart Gen-14).
Enter the value of Σma on Scale B and draw a line to Pivot Point B.
Enter Σlog on Scale B and draw Line b through the intersection of
Line a and the value of φ to intersect the sigma of the formationfluid (Σf ) on Scale C. Draw Line 5 from Σf through the intersection
of Σh and Σ w to determine the value of S w on Scale D.
Example: Clean FormationGiven: Σlog = 20 c.u., Σma = 8 c.u. (sandstone) from TDT tool,
Σh = 18 c.u., Σ w = 80 c.u. (150,000 ppm or mg/kg), andφ = 30 p.u.
Find: S w .
Answer: Following the procedure for a clean formation, S w = 43%.
V sh from porosity log crossplot or gamma ray, shale porosity (φsh) read
from a porosity log in adjacent shale, and the porosity corrected for
shaliness (φshcor) with the relation for neutron and density logs
in liquid-filled formations of φshcor = φlog – V shφsh.
Enter the value of Σma on Scale B and draw Line 1 to intersect
with Pivot Point A. From the value of Σsh on Scale A, draw Line 2
through the intersection of Line 1 and V sh to determine the shale-
corrected Σcor on Scale B. Draw Line 3 from Σcor to the value of Σma
on the scale to the left of Scale C. Enter Σlog on Scale B and draw Line 4 through the intersection of Line 3 and the value of φ to deter-
mine Σf on Scale C. From Σf on Scale C, draw Line 5 through the
intersection of Σh and Σ w to determine S w on Scale D.
Example
Given: Σlog = 25 c.u.
Σma = 8 c.u.
Σh = 18 c.u.
Σ w = 80 c.u.
Σsh = 45 c.u.
φlog = 33 p.u.
φsh = 45 p.u.
V sh = 0.2.
Find: φshcor and S w .
Answer: First find the porosity corrected for shaliness,
φshcor = 33 p.u. – (0.2 × 45 p.u.) = 24 p.u. This value
Saturation—Wireline
Capture Cross Section ToolCased Hole
SatCH-1(former Sw-12)
20 30 40 50 60sh
sh (c.u.)
A
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2
4
50 40 30 20 10 0
100 120 140 160 200 300 400
200 150 120 100 90 80
510
15
2025
3035
4045
0.1
0.5
Pivot point A
0.40.3
0.2
tsh ( s)
macor(c.u.)
t ( s)
p.u.
ab
A
B
Pivot point B
1
3
Purpose
This chart is used to graphically interpret the TDT* Thermal Decay
Time log. In one technique, applicable in shaly as well as clean
sands, the apparent water capture cross section (Σ wa ) is plotted versus bound-water saturation (S wb) on a specially constructed grid to
Saturation—Wireline
Capture Cross Section ToolCased Hole
90
85
80Bound-water
point
wb = 76
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determine the total water saturation (S wt).
DescriptionTo construct the grid, refer to the example chart on this page. Three
fluid points must be located: free-water point (Σ wf ), hydrocarbon
point (Σh), and a bound-water point (Σ wb). The free- (or connate for-
mation) water point is located on the left y-axis and can be obtained
from measurement of a formation water sample, from Charts Gen-12and Gen-13 if the water salinity is known, or from the TDT log in
a clean water-bearing sand by using the following equation:
The hydrocarbon point is also located on the left y-axis of the grid.
It can be determined from Chart Gen-14 based on the known or
expected hydrocarbon type.The bound-water point (S wb) can be obtained from the TDT log
in shale intervals also by using the Σ wa equation. It is located on the
right y-axis of the grid.
The distance between the free-water and hydrocarbon points is
linearly divided into lines of constant water saturation drawn parallel
to a straight line connecting the free-water and bound-water points.
The S wt = 0% line originates from the hydrocarbon point, and the
S wt = 100% line originates from the free-water point.
The value of Σwa from the equation is plotted versus Swb to give
0 20 40 60 80 100
Swb (%)
40 44 48 52 56 60 64 68 72 76 80
Gamma Ray(gAPI)
wa
(c.u.)
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
Free-waterpoint
wf = 61
wb
100% water line
Hydrocarbonpoint
h = 21
86 5
4
3
2
1
7
S w t = S w b
8 0
7 0
6 0
5 0
4 0
3 0
2 0
0
1 0
9 0 %
∑ =∑ − ∑
+ ∑ wa ma
ma log
.φ
(1)
*Mark of Schlumberger
Saturation—Wireline
Capture Cross Section ToolCased Hole
SatCH-2(former Sw-17)
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log
or
wa
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in.Carbon/Oxygen Ratio—Open Hole
Purpose
Charts SatCH-3 through SatCH-8 are presented for illustrative
purposes only. They are used to ensure that the measured near- and
far-detector carbon/oxygen (C/O) ratio data are consistent with theinterpretation model. These example charts are drawn for specific
consistently outside the trapezoid, the interpretation model may
require revision.
The rectangle within each chart is constructed from four distinct
points determined by the intersection of the near- and far-detectorC/O ratios:
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cased and open holes and tool sizes to provide trapezoids for the
to determination of oil saturation (So) and oil holdup (y o).
Description
Known formation and borehole data define the expected C/O ratio
values, which are determined in water saturation and borehole
holdup values ranging from 0 to 1. All log data for formations with
porosity (φ) greater than 10 p.u. should be within the trapezoidalarea bounded by the limits of the So and y o values. If data plot
WW = water/water point
WO = water/oil point
OW = oil/water point
OO = oil/oil point.
RST Reservoir Saturation Tool processing then determines the water
saturation (S w ) of the formation.
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in.in 6.125-in. BoreholeCarbon/Oxygen Ratio—Open Hole
φ = 30%, 6.125-in. Open Hole
SatCH-3(former RST-3)
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Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 6.125-in. Open Hole
RST-A and RST-C, limestoneRST A q art sandstone
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
OO
OW
WO
WW
OO
OW
WO
OO
OW
WO
WO
OW
OO
WW
WWWW
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in.in 9.875-in. BoreholeCarbon/Oxygen Ratio—Open Hole
SatCH-4
φ = 30%, 9.875-in. Open Hole
1.5
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φ = 20%, 9.875-in. Open Hole
1.5
RST-A and RST-C, limestone
1.5
1.0
0.5
0
0 1.5
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
0.5 1.0
OW
WO
WW
WO
WW
OWWO
WW
OW
OO
OO
OW
WW
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in.in 8.125-in. Borehole with 4.5-in. Casing at 11.6 lbm/ftCarbon/Oxygen Ratio—Cased Hole
SatCH-5(former RST-5)
φ = 30%, 6.125-in. Borehole, 4.5-in. Casing at 11.6 lbm/ft
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Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 6.125-in. Borehole, 4.5-in. Casing at 11.6 lbm/ft
RST-A and RST-C, limestone
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
OO
O W
WO
W W
O W
O W
O W
WO
WO
WO W W
W W
OO
OO
OO
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in.in 7.875-in. Borehole with 5.5-in. Casing at 17 lbm/ftCarbon/Oxygen Ratio—Cased Hole
SatCH-6
φ = 30%, 7.875-in. Borehole, 5.5-in. Casing at 17 lbm/ft
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Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 7.875-in. Borehole, 5.5-in. Casing at 17 lbm/ft
RST-A and RST-C, limestone
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
WO
OO
O W
OO
O W
WO
WW
WW
OW
OO
WO
WW
WW
WO
OW
OO
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in.in 8.5-in. Borehole with 7-in. Casing at 29 lbm/ftCarbon/Oxygen Ratio—Cased Hole
SatCH-7(former RST-1)
φ = 30%, 8.5-in. Borehole, 7-in. Casing at 29 lbm/ft
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Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 8.5-in. Borehole, 7-in. Casing at 29 lbm/ft
RST-A and RST-C, limestone
0.8
0.6
0.4
0.2
0
0 0.5 1.0
WO
WW
OW
OO
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
OW
OO
WO
WO
OO
OW
WW
WW
OO
OW
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in.in 9.875-in. Borehole with 7-in. Casing at 29 lbm/ftCarbon/Oxygen Ratio—Cased Hole
SatCH-8(former RST-2)
φ = 30%, 9.875-in. Borehole, 7-in. Casing at 29 lbm/ft
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Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 9.875-in. Borehole, 7-in. Casing at 29 lbm/ft
RST-A and RST-C, limestone
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
OO
OWWO
WW
OO
OWWO
WW
OO
OW
WO
WW
OO
OW
WW
WO
General
General
Permeability
Permeability from Porosity and Water SaturationOpen Hole
PurposeCharts Perm-1 and Perm-2 are used to estimate the permeability of
shales, shaly sands, or other hydrocarbon-saturated intergranular
rocks at irreducible water saturation (S wi).
Description
ExampleGiven: φ = 23 p.u., S wi = 30%, gas saturation with ρh = 0.3 g/cm3
and ρ w = 1.1 g/cm3, and h = 120 ft.
Find: Correction factor and k. Answer: First, find pc to determine the correction factor if the
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esc pt oThe charts are based on empirical observations and are similar in
form to a general expression proposed by Wyllie and Rose (1950)
(see Reference 49):
Chart Perm-1 presents the results of one study for which the
observed relation was
Chart Perm-2 presents the results of another study:
The charts are valid only for zones at irreducible water saturation.
Enter porosity (φ) and S wi on a chart. Their intersection defines
the intrinsic (absolute) rock permeability (k). Medium-gravity oil is
assumed. If the saturating hydrocarbon is other than medium-gravity
oil, a correction factor (C′) based on the fluid densities of water and
hydrocarbons (ρ w and ρh, respectively) and elevation above the free-
water level (h) should be applied to the S wi value before it is enteredon the chart The chart on this page provides the correction factor
zone of interest is not at irreducible water saturation:
Enter the correction factor chart with S wi = 30% to inter-
sect the curve for pc = 40 (nearest to 42), for which thecorrection factor is 1.08. The corrected S wi value is S´ wi =
1.08 × 30% = 32.4%.
Chart Perm-1: φS´ wi = 0.072% and k = 130 mD.
Chart Perm-2: φS´ wi = 0.072% and k = 65 mD.
kC
SC
wi
1 2 / .=
+ ′φ
kS wi
1 22 25100 / .
.=
φ
kS
Se wi
wi
1 2 2701
/ .φ = −
ph
c w h=
−( )=
−( )=
ρ ρ
2 3
120 1 1 0 3
2 342
.
. .
..
2.0
1.8
1.6
pc = 200
pc =h(ρw – ρo)
2.3
(1)
(2)
(3)
General
Permeability from Porosity and Water SaturationOpen Hole
General
Permeability
Perm-1(former K-3)
60
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50
40
30
20
10
0
Irreduciblewater
saturationabove
transitionzone,
Swi (%)
φSwi
0.12
0.10
0.08
0.06
0.04
0.02
0.01
5,000
2,0001,000
500
200
100
50
20
10
5
2
1.0
0.5
0.2
0.10.01
P e r m e a b i l i t y , k ( m D )
General
Permeability
Permeability from Porosity and Water SaturationOpen Hole
Perm-2(former K-4)
40
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35
30
25
20
15
10
5
0
Porosity,φ (p.u.)
φSwi
P e r m
e a b i l i t y , k ( m
D )
5,000
1,000
2,000
500
200
50
20
10
100
5
1
0.01
0.02
0.04
0.06
0.08
0.10
0.12
0.10
0.01
General
Permeability
Fluid Mobility Effect on Stoneley SlownessOpen Hole
Perm-3
10,000
Fresh Mud at 600 Hz
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0.1
10
100
1,000 50 10 5 1
Membrane impedance
0 GPa/cm(no mudcake)
Mobility
(mD/cp)
General
Cement Bond Log—Casing StrengthInterpretation—Cased Hole
P
urpose
This chart is used to determine the decibel attenuation of casing
from the measured cement bond log (CBL) amplitude and convert
it to the compressive strength of bonded cement (either standardor foamed).
Example
Given: Log amplitude reading = 3.5 mV in zone of interest
and 1.0 mV in a well-bonded section (usually the lowest
millivolt value on the log), casing size = 7 in. at29 lbm/ft, casing thickness = 0.41 in., and neat cement
(not foamed).
Cement Evaluation—Wireline
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Description
The amplitude of the first casing arrival is recorded by an acoustic
signal-measuring device such as a sonic or cement bond tool. This
amplitude value is a measure of decibel attenuation that can be
translated into a bond index (an indication of the percent of casing
cement bonding) and the compressive strength (psi) of the cement
at the time of logging.
Enter the chart on the y-axis with the log value of CBL amplitude
and move upward parallel to the 45° lines to intersect the appropri-
ate casing size. At that point, move horizontally right to the attenua-
tion scale on the right-hand y-axis. From this point, draw a line
through the appropriate casing thickness value to intersect the com-
pressive strength scale. The casing wall thickness is calculated by
subtracting the nominal inside diameter (ID) from the outside
diameter (OD) listed on the table for threaded nonupset casing
and dividing the difference by 2.
(not foamed).
Find: Compressive strength and bond index of the cement at
the time of logging.
Answer: Enter the 3.5-mV reading on the left y-axis of Chart
Cem-1 and proceed to the 7-in. casing line.
Move horizontally to intersect the right-hand y-axis at
8.9 dB/ft.
Determine the casing thickness as (7 – 6.184)/2 = 0.816/2
= 0.41 in. Draw a line from 8.9 dB/ft through the 0.41-in.
casing thickness point to the compressive strength scale.
Cement compressive strength = 2,100 psi.
To find the bond index, determine the decibel attenuation of the
lowest recorded log value by entering 1.0 mV on the left-hand y-axis
and proceeding to the 7-in. casing line. Move horizontally to intersect
the right-hand y-axis at 12.3 dB/ft.
Divide the precisely determined decibel attenuation for the CBL
amplitude in the zone of interest by this value for the lowest millivolt
value: 8.9/12.3 = 72% bond index.
A 72% bond index means that 72% of the casing is bonded. This
is not a well-bonded zone because a value of 80% bonding over a 10-ft
interval is historically considered well bonded. Although the logging
scale is a linear millivolts scale, the decibel attenuation scale is loga-
rithmic. The millivolts log scale for the CBL value cannot rescaled
in percent of bonding. If it were, the apparent percent bonding
would be 65% because most bond log scales are from 0 to 100 mV
OD Weight Nominal Drift
(in.) per ft† ID Diameter‡
(lbm) (in.) (in.)
10 33.00 9.384 9.228
Cement Evaluation—Wireline
Cement Bond Log—Casing StrengthInterpretation—Cased Hole
OD Weight Nominal Drift
(in.) per ft† ID Diameter‡
(lbm) (in.) (in.)
4 11.60 3.428 3.303
OD Weight Nominal Drift
(in.) per ft† ID Diameter‡
(lbm) (in.) (in.)
7 17.00 6.538 6.413
Threaded Nonupset Casing
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103 ⁄ 4 32.75 10.192 10.036
40.00 10.054 9.898
40.50 10.050 9.894
45.00 9.960 9.804
45.50 9.950 9.794
48.00 9.902 9.746
51.00 9.850 9.69454.00 9.784 9.628
55.50 9.760 9.604
113 ⁄ 4 38.00 11.150 10.994
42.00 11.084 10.928
47.00 11.000 10.844
54.00 10.880 10.724
60.00 10.772 10.616
12 40.00 11.384 11.228
13 40.00 12.438 12.282
133 ⁄ 8 48.00 12.715 12.559
16 55.00 15.375 15.187
185 ⁄ 8 78.00 17.855 17.667
20 90.00 19.190 19.002
211⁄2 92 50 20 710 20 522
41 ⁄ 2 9.50 4.090 3.965
11.60 4.000 3.875
13.50 3.920 3.795
43 ⁄ 4 16.00 4.082 3.957
5 11.50 4.560 4.435
13.00 4.494 4.369
15.00 4.408 4.283
17.70 4.300 4.175
18.00 4.276 4.151
21.00 4.154 4.029
51 ⁄ 2 13.00 5.044 4.919
14.00 5.012 4.887
15.00 4.974 4.849
15.50 4.950 4.825
17.00 4.892 4.767
20.00 4.778 4.653
23.00 4.670 4.545
53 ⁄ 4 14.00 5.290 5.165
17.00 5.190 5.065
19.50 5.090 4.965
22.50 4.990 4.865
6 15.00 5.524 5.399
16 00 5 500 5 37518 00 5 424 5 299
20.00 6.456 6.331
22.00 6.398 6.273
23.00 6.366 6.241
24.00 6.336 6.211
26.00 6.276 6.151
28.00 6.214 6.089
29.00 6.184 6.059
30.00 6.154 6.02932.00 6.094 5.969
35.00 6.004 5.879
38.00 5.920 5.795
40.00 5.836 5.711
75 ⁄ 8 20.00 7.125 7.000
24.00 7.025 6.900
26.40 6.969 6.844
29.70 6.875 6.750
33.70 6.765 6.640
39.00 6.625 6.500
85 ⁄ 8 24.00 8.097 7.972
28.00 8.017 7.892
32.00 7.921 7.796
36.00 7.825 7.700
38.00 7.775 7.650
40.00 7.725 7.600
43 00 7 651 7 526
General
Cement Bond Log—Casing StrengthInterpretation—Cased Hole
Cem-1(former M-1)
Cement Evaluation—Wireline
Casing size (mm) Centered tool only, 3-ft [0.914-m] spacing
Att ti
115140
194
176273
340
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Casing thickness(mm) (in.)
CBL amplitude(mV)
Attenuation(dB/m)
15
10
1
2
3
4
5
6
7
8
9
10
4
8
12
16
20
24
28
32
70
50
40
30
20
15
10987
6
5
4
3
8
7
0.3
0.4
0.5
0.6
7 i n. a t 2 9 l b
m
Compressive strength(psi)
(mPa)
Standardcement1 000
30
25
20
15
10
4,000
3,000
2,000
1,000
Appendix A Linear Grid
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Appendix A
Appendix A
9
8
7
6
5
Log-Linear Grid
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4
3
2
1
9
8
7
6
Appendix A
Appendix A
0.20
0.25
5,000
4,000
Resistivity scale may bemultiplied by 10 for usein a higher range
For FR =0.62
φ2.15
Water Saturation Grid for Resistivity Versus Porosity
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0.30
0.35
0.40
0.45
0.50
0.60
0.70
0.80
0.90
1.0
1.2
1.4
1.6
1.82.0
3,000
2,500
2,000
1,500
1,000
500
Conductivity(mmho/m)
Resistivity(ohm-m)
Appendix A
Appendix A
2
2.5
500
400
Resistivity scale may bemultiplied by 10 for usein a higher range
For FR =1
φ2
Water Saturation Grid for Resistivity Versus Porosity
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3
3.5
4
4.5
5
6
7
8
9
10
12
14
16
20
300
250
200
150
100
50
Conductivity(mmho/m)
Resistivity(ohm-m)
Appendix B Logging Tool Response in Sedimentary Minerals
Name Formula ρlog φSNP φCNL φAPS† ∆ tc ∆ ts Pe U ε tp Gamma Ray Σ
(g/cm3) (p.u.) (p.u.) (p.u.) (µs/ft) (µs/ft) (farad/m) (ns/m) (gAPI Units) (c.u.)
Silicates
Quartz SiO2 2.64 –1 –2 –1 56.0 88.0 1.8 4.8 4.65 7.2 4.3
β-cr is tobali te S iO2 2.15 –2 –3 1.8 3.9 3.5
Opal (3.5% H2O) SiO2 (H2O)0.1209 2.13 4 2 58 1.8 3.7 5.0
Garnet‡ Fe3Al2(SiO4)3 4.31 3 7 11 48 45
Hornblende‡ Ca2NaMg2Fe2
AlSi8O22(O OH)23.20 4 8 43.8 81.5 6.0 19 18
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AlSi8O22(O,OH)2
Tourmaline NaMg3Al6B3Si6O2(OH)4 3.02 16 22 2.1 6.5 7450
Zircon ZrSiO4 4.50 –1 –3 69 311 6.9
Carbonates
Calcite CaCO3 2.71 0 0 0 49.0 88.4 5.1 13.8 7.5 9.1 7.1
Dolomite CaCO3MgCO3 2.85 2 1 1 44.0 72 3.1 9.0 6.8 8.7 4.7
Ankerite Ca(Mg,Fe)(CO3)2 2.86 0 1 9.3 27 22
Siderite FeCO3 3.89 5 12 3 47 15 57 6.8–7.5 8.8–9.1 52
Oxidates
Hematite Fe2O3 5.18 4 11 42.9 79.3 21 111 101
Magnetite Fe3O4 5.08 3 9 73 22 113 103
Goethite FeO(OH) 4.34 50+ 60+ 19 83 85
Limonite‡ FeO(OH)(H2O)2.05 3.59 50+ 60+ 56.9 102.6 13 47 9.9–10.9 10.5–11.0 71
Gibbsite Al(OH)3 2.49 50+ 60+ 1.1 23
Phosphates
Hydroxyapatite Ca5(PO4)3OH 3.17 5 8 42 5.8 18 9.6
Chlorapatite Ca5(PO4)3Cl 3.18 –1 –1 42 6.1 19 130
Fluorapatite Ca5(PO4)3F 3.21 –1 –2 42 5.8 19 8.5
Carbonapati te (Ca5(PO4)3)2CO3H2O 3.13 5 8 5.6 17 9.1
F ld Alk li‡
Appendix B Logging Tool Response in Sedimentary Minerals
Name Formula ρlog φSNP φCNL φAPS† ∆ tc ∆ ts Pe U ε tp Gamma Ray Σ
(g/cm3) (p.u.) (p.u.) (p.u.) (µs/ft) (µs/ft) (farad/m) (ns/m) (gAPI Units) (c.u.)
Clays‡
Kaolinite Al4Si4O10(OH)8 2.41 34 ~37 ~34 1.8 4.4 ~5.8 ~8.0 80–130 14
Chlorite(Mg,Fe,Al)6(Si,Al)4
2.76 37 ~52 ~35 6.3 17 ~5.8 ~8.0 180–250 25O10(OH)8
Illite
K1–1.5Al4(Si7–6.5,Al1–1.5)
2.52 20 ~30 ~17 3.5 8.7 ~5.8 ~8.0 250–300 18O20(OH)4
Montmorillonite(Ca,Na)7(Al,Mg,Fe)4
2 12 ~60 ~60 2 0 4 0 ~5 8 ~8 0 150–200 14(Si Al) O (OH) (H O)
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Montmorillonite 2.12 60 60 2.0 4.0 5.8 8.0 150 200 14(Si,Al)8O20(OH)4(H2O)n
Evaporites
Halite NaCl 2.04 –2 –3 21 67.0 120 4.7 9.5 5.6–6.3 7.9–8.4 754
Anhydrite CaSO4 2.98 –1 –2 2 50 5.1 15 6.3 8.4 12
Gypsum CaSO4(H2O)2 2.35 50+ 60+ 60 52 4.0 9.4 4.1 6.8 19
Trona Na2CO3NaHCO3H2O 2.08 24 35 65 0.71 1.5 16
Tachhydrite CaCl2(MgCl2)2(H2O)12 1.66 50+ 60+ 92 3.8 6.4 406
Sylvite KCl 1.86 –2 –3 8.5 16 4.6–4.8 7.2–7.3 500+ 565
Carnalite KClMgCl2(H2O)6 1.57 41 60+ 4.1 6.4 ~220 369
Langbeinite K2SO4(MgSO4)2 2.82 –1 –2 3.6 10 ~290 24
PolyhaliteK2SO4Mg
2.79 14 25 4.3 12 ~200 24SO4(CaSO4)2(H2O)2
Kainite MgSO4KCl(H2O)3 2.12 40 60+ 3.5 7.4 ~245 195
Kieserite MgSO4(H2O) 2.59 38 43 1.8 4.7 14
Epsomite MgSO4(H2O)7 1.71 50+ 60+ 1.2 2.0 21
Bischofite MgCl2(H2O)6 1.54 50+ 60+ 100 2.6 4.0 323
Barite BaSO4 4.09 –1 –2 267 1090 6.8
Celestite SrSO4 3.79 –1 –1 55 209 7.9
Sulfides
Pyrite FeS 4 99 2 3 39 2 62 1 17 85 90
Appendix C
Appendix C Acoustic Characteristics of Common Formations and Fluids
Nonporous Solids
Material ∆ t Sound Velocity Acoustic Impedance
(µs/ft) (ft/s) (m/s) (MRayl)
Casing 57.0 17,500 5,334 41.60
Dolomite 43.5 23,000 7,010 20.19
Anhydrite 50.0 20,000 6,096 18.17
Limestone 47.6 21,000 6,400 17.34
Calcite 49.7 20,100 6,126 16.60
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Calcite 49.7 20,100 6,126 16.60
Quartz 52.9 18,900 5,760 15.21
Gypsum 52.6 19,000 5,791 13.61
Halite 66.6 15,000 4,572 9.33
Water-Saturated Porous Rock
Material Porosity ∆ t Sound Velocity Acoustic Impedance
(%) (µs/ft) (ft/s) (m/s) (MRayl)
Dolomite 5–20 50.0–66.6 20,000–15,000 6,096–4,572 16.95–11.52
Limestone 5–20 54.0–76.9 18,500–13,000 5,639–3,962 14.83–9.43
Sandstone 5–20 62.5–86.9 16,000–11,500 4,877–3,505 12.58–8.20
Sand 20–35 86.9–111.1 11,500–9,000 3,505–2,743 8.20–6.0
Shale 58.8–143.0 17,000–7,000 5,181–2,133 12.0–4.3
Nonporous Solids
Material ∆ t Sound Velocity Acoustic Impedance
(µs/ft) (ft/s) (m/s) (MRayl)
Water 208 4 800 1 463 1 46
Appendix D Conversions
Length
Multiply Centimeters Feet Inches Kilometers Nautical Meters Mils Miles Millimeters YardsNumber Miles
of toObtain by
Centimeters 1 30.48 2.540 105 1.853 × 105 100 2.540 × 10–3 1.609 × 105 0.1 91.44
Feet 3.281×
10–2
1 8.333×
10–2
3281 6080.27 3.281 8.333×
10–5
5280 3.281×
10–3
3
Inches 0.3937 12 1 3.937 × 104 7.296 × 104 39.37 0.001 6.336 ×104 3.937 × 10–2 36
5 4 5 8 6 4
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Kilometers 10–5 3.048 × 10–4 2.540 × 10–5 1 1.853 0.001 2.540 × 10–8 1.609 10–6 9.144 × 10–4
Nautical miles 1.645 × 10–4 0.5396 1 5.396 ×10–4 0.8684 4.934 ×10–4
Meters 0.01 0.3048 2.540 × 10–2 1000 1853 1 1609 0.001 0.9144
Mils 393.7 1.2 × 104 1000 3.937 × 107 3.937 × 104 1 39.37 3.6 × 104
Miles 6.214 × 10–6 1.894 × 10–4 1.578 × 10–5 0.6214 1.1516 6.214 × 10–4 1 6.214 × 10–7 5.682 × 10–4
Millimeters 10 304.8 25.40 105 1000 2.540 × 10–2 1 914.4
Yards 1.094 × 10–2 0.3333 2.778 × 10–2 1094 2027 1.094 2.778 × 10–5 1760 1.094 × 10–3 1
Area
Multiply Acres Circular Square Square Square Square Square Square Square SquareNumber Mils Centimeters Feet Inches Kilometers Meters Miles Millimeters Yards
of
toObtain by
Acres 1 2.296 × 10–5 247.1 2.471 × 10–4 640 2.066 × 10–4
Circular mils 1 1.973 × 105 1.833 × 108 1.273 × 106 1.973 ×109 1973
Squarecentimeters 5.067 × 10–6 1 929.0 6.452 1010 104 2.590 × 1010 0.01 8361
Square feet 4.356 × 104 1.076 × 10–3 1 6.944 × 10–3 1.076 × 107 10.76 2.788 × 107 1.076 × 10–5 9
Square inches 6,272,640 7.854 × 10–7 0.1550 144 1 1.550 × 109 1550 4.015 × 109 1.550 × 10–3 1296
Appendix D Conversions
Volume
Multiply Bushels Cubic Cubic Cubic Cubic Cubic Gallons Liters Pints QuartsNumber (Dry) Centimeters Feet Inches Meters Yards (Liquid) (Liquid) (Liquid)
of toObtain by
Bushels (dry) 1 0.8036 4.651 × 10–4 28.38 2.838 × 10–2
Cubiccentimeters 3.524 × 104 1 2.832 × 104 16.39 106 7.646 × 105 3785 1000 473.2 946.4
Cubic feet 1.2445 3.531 × 10–5 1 5.787 × 10–4 35.31 27 0.1337 3.531 × 10–2 1.671 × 10–2 3.342 × 10–2
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Cubic inches 2150.4 6.102 × 10–2 1728 1 6.102 × 104 46,656 231 61.02 28.87 57.75
Cubic meters 3.524 × 10–2 10–6 2.832 × 10–2 1.639 × 10–5 1 0.7646 3.785 × 10–3 0.001 4.732 × 10–4 9.464 × 10–4
Cubic yards 1.308 × 10–6 3.704 × 10–2 2.143 × 10–5 1.308 1 4.951 × 10–3 1.308 × 10–3 6.189 × 10–4 1.238 × 10–3
Gallons(liquid) 2.642 × 10–4 7.481 4.329 × 10–3 264.2 202.0 1 0.2642 0.125 0.25
Liters 35.24 0.001 28.32 1.639 × 10–2 1000 764.6 3.785 1 0.4732 0.9464
Pints (liquid) 2.113 × 10–3 59.84 3.463 × 10–2 2113 1616 8 2.113 1 2
Quarts (liquid) 1.057 × 10–3 29.92 1.732 × 10–2 1057 807.9 4 1.057 0.5 1
Mass and Weight
Multiply Grains Grams Kilograms Milligrams Ounces† Pounds† Tons Tons Tons
Number (Long) (Metric) (Short)of toObtain by
Grains 1 15.43 1.543 × 104 1.543 × 10–2 437.5 7000
Grams 6.481 × 10–2 1 1000 0.001 28.35 453.6 1.016 × 106 106 9.072 × 105
Kilograms 6.481 × 10–5 0.001 1 10–6 2.835 × 10–2 0.4536 1016 1000 907.2
Milligrams 64.81 1000 106 1 2.835 × 104 4.536 × 105 1.016 × 109 109 9.072 × 108
Ounces† 2 286 × 10–3 3 527 × 10–2 35 27 3 527 × 10–5 1 16 3 584 × 104 3 527 × 104 3 2 × 104
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Appendix E Symbols
Traditional Standard Standard Description Customary Unit or Relation StandardSymbol SPE Computer Reserve
and Symbol† Symbol‡
SPWLA†
a a ACT electrochemical activity equivalents/liter, moles/liter
a KR COER coefficient in FR – φ relation FR = KR /φm MR, a, C
A A AWT atomic weight amu
C C ECN conductivity (electrical logging) millimho per meter (mmho/m) σCp Bcp CORCP sonic compaction correction factor φSVcor = BcpφSV Ccp
D D DPH d th ft H
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D D DPH depth ft, m y, H
d d DIA diameter in. D
E E EMF electromotive force mV V
F FR FACHR formation resistivity factor FR = KR /φm
G G GMF geometrical factor (multiplier) fG
H IH HYX hydrogen index iH
h h THK bed thickness, individual ft, m, in. d, e
I I –X index i
FFI IFf FFX free fluid index iFf
SI Isl SLX silt index Islt, isl, islt
Iφ PRX porosity index iφ
SPI Iφ2 PRXSE secondary porosity index iφ2
J Gp GMFP pseudogeometrical factor fGp
K Kc COEC electrochemical SP coefficient Ec = Kclog(aw /amf) Mc, Kec
k k PRM permeability, absolute (fluid flow) mD K
L L LTH length, path length ft, m, in. s, l
M M SAD slope, sonic interval transit time versus M = [(τf – τLOG)/(ρb – ρf)] × 0.01 mθD
density × 0.01, in M–N plot
m m MXP porosity (cementation) exponent FR = KR /φm
Appendix E Symbols
Traditional Standard Standard Description Customary Unit or Relation StandardSymbol SPE Computer Reserve
and Symbol† Symbol‡
SPWLA†
Qv shaliness (CEC per mL water) meq/mL
q fφ shd FIMSHD dispersed-shale volume fraction of φ imfshd, q
intermatrix porosity
R R RES resistivity (electrical) ohm-m ρ, r
r r RAD radial distance from hole axis in. R
S S SAT saturation fraction or percent ρ, s
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p ρ,
of pore volume
T T TEM temperature °F, °C, K θ
BHT, Tbh Tbh TEMBH bottomhole temperature °F, °C, K θBH
FT, Tfm Tf TEMF formation temperature °F, °C, K
t t TIM time µs, s, min t
t t TAC interval transit time ∆ t
U volumetric cross section barns/cm3
v v VAC velocity (acoustic) ft /s, m/s V, u
V V VOL volume cm3, ft3, etc. v
V V VLF volume fraction fv, Fv
Z Z ANM atomic number
α αSP REDSP SP reduction factorγ γ SPG specific gravity (ρ /ρw or ρg /ρair) s, Fs
φ φ POR porosity fraction or percentage f, ε
of bulk volume, p.u.
φ1 PORPR primary porosity fraction or percentage f1, e1
of bulk volume, p.u.
φ2 PORSE secondary porosity fraction or percentage f2, e2
of bulk volume, p.u.
φi PORIG intergranular porosity φi = (Vb V )/Vb fi εi
Appendix E
Appendix F Subscripts
Traditional Standard Standard Explanation Example StandardSubscript SPE Computer Reserve
and Subscript† Subscript‡
SPWLA†
a LOG L apparent from log reading RLOG, RLL log
(or use tool description subscript)
a a A apparent (general) Ra ap
abs cap C absorption, capture Σcap
anh anh AH anhydrite
b b B bulk ρb B, t
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ρb
bh bh BH bottomhole Tbh w, BH
clay cl CL clay Vcl cla
cor, c cor COR corrected tcor
c c C electrochemical Ec ec
cp cp CP compaction Bcp
D D D density log d
dis shd SHD dispersed shale Vshd
dol dol DL dolomite tdol
e, eq eq EV equivalent Rweq, Rmfeq EV
f, fluid f F fluid ρf fl
fm f F formation (rock) Tf fm
g, gas g G gas Sg G
gr GR grain ρgr
gxo gxo GXO gas in flushed zone Sgxo GXO
gyp gyp GY gypsum ρgyp
h h H hole dh H
h h H hydrocarbon ρh H
hr hr HR residual hydrocarbon Shr
Appendix E
Appendix F Subscripts
Traditional Standard Standard Explanation Example StandardSubscript SPE Computer Reserve
and Subscript† Subscript‡
SPWLA†
log LOG L log values tLOG log
ls ls LS limestone t ls lst
m m M mud Rm
max max MX maximum φmax
ma ma MA matrix tma
mc mc MC mudcake R
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mc mc MC mudcake Rmc
mf mf MF mud filtrate Rmf
mfa mfa MFA mud filtrate, apparent Rmfa
min min MN minimum value
ni noninvaded zone Rni
o o O oil (except with resistivity) So N
or or OR residual oil Sor
o, 0 (zero) 0 (zero) ZR 100-percent water saturated F0 zr
p propagation tpw
PSP pSP PSP pseudostatic SP EpSP
pri 1 (one) PR primary φ1 p, pri
r r R relative kr o, krw R
r r R residual Sor, Shr R
s s S adjacent (surrounding) formation Rs
sd sd SD sand sa
ss ss SS sandstone sst
sec 2 SE secondary φ2 s, sec
sh sh SH shale Vsh sha
silt sl SL silt Isl slt
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Appendix F
Appendix G Unit Abbreviations
These unit abbreviations, which are based on those adopted by the
Society of Petroleum Engineers (SPE), are appropriate for most publi-
cations. However, an accepted industry standard may be used instead.
For instance, in the drilling field, ppg may be more common than
lbm/gal when referring to pounds per gallon.
In some instances, two abbreviations are given: customary and
metric. When using the International System of Units (SI), or metric,
abbreviations, use the one designated for metric (e.g., m3 /h instead of
m3 /hr). The use of SI prefix symbols and prefix names with customary unit abbreviations and names, although common, is not preferred
(e.g., 1,000 lbf instead of klbf).
curie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ci
dalton. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Da
darcy, darcies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D
day (customary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D
day (metric). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . d
dead-weight ton. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DWT
decibel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dB
degree (American Petroleum Institute). . . . . . . . . . . . . . . . . . . . . . . . . . . °API
degree Celsius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . °C
degree Fahrenheit °F
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( g , , )
Unit abbreviations are followed by a period only when the abbrevia-
tion forms a word (for example, in. for inch).
acre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spell out
acre-foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . acre-ft
ampere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A
ampere-hour. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-hr
angstrom unit (10–8 cm). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A
atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . atm
atomic mass unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . amu
barrel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . bbl
barrels of fluid per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BFPD
barrels of liquid per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BLPD
barrels of oil per day. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BOPDbarrels of water per day. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BWPD
barrels per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B/D
barrels per minute. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . bbl/min
billion cubic feet (billion = 109) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bcf
billion cubic feet per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bcf/D
billion standard cubic feet per day . . . . . . . . . . . Use Bcf/D instead of Bscf/D
(see “standard cubic foot”)
bits per inch bpi
degree Fahrenheit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . °F
degree Kelvin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See “kelvin”
degree Rankine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . °R
dots per inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dpi
electromotive force. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . emf
electron volt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . eV farad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F
feet per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft/min
feet per second. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft/s
foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft
foot-pound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft-lbf
gallon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . gal
gallons per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . gal/D
gallons per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . gal/mingigabyte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gbyte
gigahertz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GHz
gigapascal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GPa
gigawatt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GW
gram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . g
hertz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hz
horsepower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . hp
h h h h
Appendix G
lines per inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lpi
lines per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lpm
lines per second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lps
liter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L
megabyte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MB
megagram (metric ton). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mg
megahertz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MHz
megajoule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MJ
meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . m
metric ton (tonne) t or Mg
pounds of proppant added . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ppa
pounds per square inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . psi
pounds per square inch absolute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . psia
pounds per square inch gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . psig
pounds per thousand barrels (salt content). . . . . . . . . . . . . . . . . . . . . . . . . ptb
quart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . qt
reservoir barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . res bbl
reservoir barrel per day. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RB/D
revolutions per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . rpm
saturation unit s u
Appendix G Unit Abbreviations
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metric ton (tonne) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . t or Mg
mho per meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ω /m
microsecond. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . µs
mile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spell out
miles per hour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mph
milliamperes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mA millicurie. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mCi
millidarcy, millidarcies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mD
milliequivalent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . meq
milligram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mg
milliliter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mL
millimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mm
millimho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mmho
million cubic feet (million = 106) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MMcf million cubic feet per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MMcf/D
million electron volts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MeV
million standard cubic feet per day . . . . . . . Use MMcf/D instead of MMscf/D
(see “standard cubic foot”)
milliPascal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mPa
millisecond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ms
millisiemens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mS
millivolt mV
saturation unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s.u.
second. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s
shots per foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . spf
specific gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sg
square . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sq
square centimeter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cm
2
square foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft2
square inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . in. 2
square meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . m2
square mile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sq mile
square millimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mm2
standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . std
standard cubic feet per day. . . . . . . . . . . . . . . . . . . . Use ft 3 /D instead of scf/D
(see “standard cubic foot”)standard cubic foot . . . . . . . . . . . . . . . . . Use ft3 or cf as specified on this list.
Do not use scf unless the standard
conditions at which the measurement
was made are specified.
The straight volumetric conversion factor
is 1 ft3 = 0.02831685 m3
stock-tank barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STB
stock-tank barrels per day. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STB/D
stoke St
Ω
Appendix G
Appendix H References
1. Overton HL and Lipson LB: “A Correlation of the Electrical
Properties of Drilling Fluids with Solids Content,” Transactions,
AIME (1958)
2. Desai KP and Moore EJ: “Equivalent NaCl Concentrations from
Ionic Concentrations,” The Log Analyst (May–June 1969).
3. Gondouin M, Tixier MP, and Simard GL: “An Experimental Study
on the Influence of the Chemical Composition of Electrolytes on
the SP Curve,” JPT (February 1957).4. Segesman FF: “New SP Correction Charts,” Geophysics
(December 1962)
No. 6, PI.
18. Wyllie MRJ, Gregory AR, and Gardner GHF: “Elastic Wave
Velocities in Heterogeneous and Porous Media,” Geophysics
(January 1956) No. 1.
19. Tixier MP, Alger RP, and Doh CA: “Sonic Logging,” JPT (May
1959) No. 5.
20. Raymer LL, Hunt ER, and Gardner JS: “An Improved Sonic
Transit Time-to-Porosity Transform,” Transactions of the
SPWLA 21st Annual Logging Symposium (1980).21. Coates GR and Dumanoir JR: “A New Approach to Improved
Log-Derived Permeability,” The Log Analyst (January–February
1974)
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5. Alger RP, Locke S, Nagel WA, and Sherman H: “The Dual Spacing
Neutron Log–CNL,” paper SPE 3565, presented at the 46th SPE
Annual Meeting, New Orleans, Louisiana, USA (1971).
6. Segesman FF and Liu OYH: “The Excavation Effect,”
Transactions of the SPWLA 12th Annual Logging Symposium
(1971).
7. Burke JA, Campbell RL Jr, and Schmidt AW: “The Litho-Porosity
Crossplot,” Transactions of the SPWLA 10th Annual Logging
Symposium (1969), paper Y.
8. Clavier C and Rust DH: “MID-PLOT: A New Lithology
Technique,” The Log Analyst (November–December 1976).
9. Tixier MP, Alger RP, Biggs WP, and Carpenter BN: “Dual
Induction-Laterolog: A New Tool for Resistivity Analysis,” paper
713, presented at the 38th SPE Annual Meeting, New Orleans,
Louisiana, USA (1963).
10. Wahl JS, Nelligan WB, Frentrop AH, Johnstone CW, and
Schwartz RJ: “The Thermal Neutron Decay Time Log,” SPEJ
(December 1970).
11. Clavier C, Hoyle WR, and Meunier D: “Quantitative
Interpretation of Thermal Neutron Decay Time Logs, Part I and
II,” JPT (June 1971).
12. Poupon A, Loy ME, and Tixier MP: “A Contribution to Electrical
Log Interpretation in Shaly Sands ” JPT (June 1954)
1974).
22. Raymer LL: “Elevation and Hydrocarbon Density Correction for
Log-Derived Permeability Relationships,” The Log Analyst
(May–June 1981).
23. Westaway P, Hertzog R, and Plasic RE: “The Gamma
Spectrometer Tool, Inelastic and Capture Gamma Ray
Spectroscopy for Reservoir Analysis,” paper SPE 9461,
presented at the 55th SPE Annual Technical Conference
and Exhibition, Dallas, Texas, USA (1980).
24. Quirein JA, Gardner JS, and Watson JT: “Combined Natural
Gamma Ray Spectral/Litho-Density Measurements Applied to
Complex Lithologies,” paper SPE 11143, presented at the 57th
SPE Annual Technical Conference and Exhibition, New Orleans,
Louisiana, USA (1982).
25. Harton RP, Hazen GA, Rau RN, and Best DL: “ElectromagneticPropagation Logging: Advances in Technique and
Interpretation,” paper SPE 9267, presented at the 55th SPE
Annual Technical Conference and Exhibition, Dallas, Texas,
USA (1980).
26. Serra O, Baldwin JL, and Quirein JA: “Theory and Practical
Application of Natural Gamma Ray Spectrometry,” Transactions
of the SPWLA 21st Annual Logging Symposium (1980).
27 Gardner JS and Dumanoir JL “Litho Density Log
Appendix H
31. Freedman R and Grove G: “Interpretation of EPT-G Logs in the
Presence of Mudcakes,” paper presented at the 63rd SPE
Annual Technical Conference and Exhibition, Houston, Texas,
USA (1988).
32. Gilchrist WA Jr, Galford JE, Flaum C, Soran PD, and Gardner JS:
“Improved Environmental Corrections for Compensated
Neutron Logs,” paper SPE 15540, presented at the 61st SPE
Annual Technical Conference and Exhibition, New Orleans,
Louisiana, USA (1986).
33. Tabanou JR, Glowinski R, and Rouault GF: “SP Deconvolution
and Quantitative Interpretation in Shaly Sands ” Transactions
40. Brie A, Johnson DL, and Nurmi RD: “Effect of Spherical Pores
on Sonic and Resistivity Measurements,” Transactions of the
SPWLA 26th Annual Logging Symposium (1985).
41. Serra O: Element Mineral Rock Catalog, Schlumberger (1990).
42. Grove GP and Minerbo GN: “An Adaptive Borehole Correction
Scheme for Array Induction Tools,” Transactions of the SPWLA
32nd Annual Logging Symposium, Midland, Texas, USA, June
16–19, 1991, paper F.43. Barber T and Rosthal R: “Using a Multiarray Induction Tool to
Achieve Logs with Minimum Environmental Effects,” paper SPE
22725 t d t SPE A l T h i l C f d
Appendix H References
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and Quantitative Interpretation in Shaly Sands, Transactions
of the SPWLA 28th Annual Logging Symposium (1987).
34. Kienitz C, Flaum C, Olesen J-R, and Barber T: “Accurate Logging
in Large Boreholes,” Transactions of the SPWLA 27th Annual
Logging Symposium (1986).
35. Galford JE, Flaum C, Gilchrist WA Jr, and Duckett SW:
“Enhanced Resolution Processing of Compensated NeutronLogs, paper SPE 15541, presented at the 61st SPE Annual
Technical Conference and Exhibition, New Orleans, Louisiana,
USA (1986).
36. Lowe TA and Dunlap HF: “Estimation of Mud Filtrate Resistivity
in Fresh Water Drilling Muds,” The Log Analyst (March–April
1986).
37. Clark B, Luling MG, Jundt J, Ross M, and Best D: “A Dual Depth
Resistivity for FEWD,” Transactions of the SPWLA 29th Annual Logging Symposium (1988).
38. Ellis DV, Flaum C, Galford JE, and Scott HD: “The Effect of
Formation Absorption on the Thermal Neutron Porosity
Measurement,” paper presented at the 62nd SPE Annual
Technical Conference and Exhibition, Dallas, Texas, USA (1987).
39. Watfa M and Nurmi R: “Calculation of Saturation, Secondary
Porosity and Producibility in Complex Middle East Carbonate
Reservoirs,” Transactions of the SPWLA 28th Annual Logging
Symposium (1987)
22725, presented at SPE Annual Technical Conference and
Exhibition, Dallas, Texas, USA, October 6–9, 1991.
44. Moran JH: “Induction Method and Apparatus for Investigating
Earth Formations Utilizing Two Quadrature Phase Components of
a Detected Signal,” US Patent No. 3,147,429 (September 1, 1964).
45. Barber TD: “Phasor Processing of Induction Logs Including
Shoulder and Skin Effect Correction,” US Patent No. 4,513,376
(September 11, 1984).
46. Barber T et al.: “Interpretation of Multiarray Induction Logs
in Invaded Formations at High Relative Dip Angles,” The Log
Analyst 40, no. 3 (May–June 1990): 202–217.
47. Anderson BI and Barber TD: Induction Logging, Sugar Land,
Texas, USA: Schlumberger Wireline & Testing, 1995 (SMP-7056).
48. Gerritsma CJ, Oosting PH, and Trappeniers NJ: “Proton Spin-
Lattice Relaxation and Self Diffusion in Methanes, II,” Physica51 (1971), 381–394.
49. Wyllie MRJ and Rose WD: “Some Theoretical Considerations
Related to the Quantitative Evaluation of the Physical
Characteristics of Reservoir Rock from Electrical Log Data,”
JPT 2 (1950), 189.
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The Schlumberger chartbook was initially developed tocorrect raw measurements to account for environmentaleffects and to interpret the corrected measurements.
Although software may be more effective in deriving results,especially in complex well situations, the chartbook still
serves two primary functions, for training and sensitivityanalysis.
Entering the chartbook will take you to the contents, fromwhere you can access any chart by clicking its entry.
You can also browse the PDF normally.
Enter the chartbook HERE.u
The Schlumberger chartbook was initially developed tocorrect raw measurements to account for environmentaleffects and to interpret the corrected measurements.
Although software may be more effective in deriving results,especially in complex well situations, the chartbook still
serves two primary functions, for training and sensitivityanalysis.
Entering the chartbook will take you to the contents, fromwhere you can access any chart by clicking its entry.
You can also browse the PDF normally.
Enter the chartbook HERE. u
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