R O C K Y M O U N T A I N SNMR APPLICATIONS IN TIGHT GAS SANDSTONE

AND SHALE GAS RESERVOIRSDick Merkel

–Clay bound water (VCBW)–Tight Gas Sand Data–Core-Log Modeling Comparison–Shale Gas NMR Core/Log Data–Shale Oil Source Rock NMR–Discussion–Conclusions

OUTLINE

Why NMR?

It directly measures:1. Irreducible Water (BVWI)2. Free Water3. Chemically Bound Water (VCBW)4. Mud Filtrate (OBM,WBM)5. Oil6. Gas7. Log Measurements @ Reservoir P/T8. Core Measurements @ Native State

Tight Gas Sand Models

Uinta Basin Mesaverde

CLAY ROMA_dry ROMA_wet VCBW CEC

Illite 2.78 2.53 0.14 0.25Kaolinite 2.68 2.62 0.036 0.10Chlorite 2.94 2.78 0.08 0.15Smectite 2.79 2.12 0.37 1.0

log

or

humidity

dried

core

NMR T2 Distribution

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0.50

0.60

0.70

0.1 1 10 100 1000 10000

T2 Relaxation Time (ms)

Incr

emen

tal P

oros

ity (%

)

0

2

4

6

8

10

12

14

Cum

ulat

ive

Poro

sity

(%)

Incremental

Cumulative

Core Native State NMR T2 Distribution in Shaly Interval

VCBW

VCBW

MRIL T2 SPECTRA9692-9698 feet

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40

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T2 Bins (ms)

Relat

ive A

mplitu

deMRIL T1 SPECTRA

9692-9698 feet

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30

35

0.5 1 2 4 8 16 32 64 128 256 512 1024 2048

T1 Bins (ms)

Relat

ive A

mplitu

de

NMR Log Bin Distributions of T1 and T2 Summed over

a Six Foot Shaly Interval

The Bin DistributionsGive the Value of

VCBW

Cum

ulat

ive

Poro

sity

(%)

Cum

ulat

ive

Poro

sity

(%)

VCBW

VCBW

VCBW (from NMR T1)vs.

Deep Resistivity

The Intercept @ VCBW=1Gives Rwb for this

Clay at this Temperature

For a Clay Change and/orDifferent Depths, Rwb

Varies, but not the Slope

Rwb

RT = Rwb / VCBW

Ct = Cwb* VCBW

For a shale interval:

VCBW = Φand since

RT = Rwb / Φm

m = 1.0

MRIL T1 SPECTRA10255-10259 feet

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T1 Bins (ms)

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ive A

mplitu

de

MRIL T2 SPECTRA10255-10259 feet

0

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16

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T2 Bins (ms)

Relat

ive A

mplitu

de

NMR Log Bin Distributionsof T1 and T2 Summed over

Six Feet in a Gas Sand

VCBW can be measuredIn both T1 and T2 space

The Gas Signal is Identifiedat T1>1024ms, but

Imbedded in the LiquidSignal in T2 Space

PVT – HI correction to thegas signal yields PHIT

VCBW correction gives PHIE

Cum

ulat

ive

Poro

sity

(%)

Cum

ulat

ive

Poro

sity

(%)

VCBW

VCBW

gas

BVWI

BVXO

Native State vs. Cleaned/Dried

Fresh State Dean-Stark

BasicPerm-

Pc-Pore (throat)& Grain Size

Relationsfor

ConstantPHI

CONVERSION TO GAS/WATER SYSTEM

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200

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1600

1800

2000

0.00 0.20 0.40 0.60 0.80 1.00Pseudo-Wetting Phase Sat'n, fraction

Gas

/Wat

er P

ress

ure,

psi

a

Sample: 172Sm Depth, feet: 9511.0 ambient 800psi 2000psi

Klinkenberg Permeability, md: 0.031 0.005 0.003Permeability to Air, md: 0.075 0.011 0.008

Swanson Permeability, md: 0.012 - -Porosity, fraction: 0.076 0.079 0.077

Host Plug

CONVERSION TO GAS/WATER SYSTEM

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200

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800

1000

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1400

1600

1800

2000

0.00 0.20 0.40 0.60 0.80 1.00

Pseudo-Wetting Phase Sat'n, fraction

Gas

/Wat

er P

ress

ure,

psi

a

Sample: 132Sm Depth, feet: 9048.65 ambient 800psi 2000psi

Klinkenberg Permeability, md: 0.805 0.443 0.338Permeability to Air, md: 1.15 0.512 0.394

Swanson Permeability, md: 0.636 - -Porosity, fraction: 0.103 0.107 0.104

Host Plug

Sample: 172Sm Depth, feet: 9511.0 ambient 800psi 2000psi

Klinkenberg Permeability, md: 0.031 0.005 0.003Permeability to Air, md: 0.075 0.011 0.008

Swanson Permeability, md: 0.012 - -Porosity, fraction: 0.076 0.079 0.077maximum Sb/Pc, fraction: 0.0022R35, microns: 0.0658

R50 (median pore throat radius): 0.0289

Host Plug Sample: 132Sm Depth, feet: 9048.65 ambient 800psi 2000psi

Klinkenberg Permeability, md: 0.805 0.443 0.338Permeability to Air, md: 1.15 0.512 0.394

Swanson Permeability, md: 0.636 - -Porosity, fraction: 0.103 0.107 0.104maximum Sb/Pc, fraction: 0.022R35, microns: 0.548

R50 (median pore throat radius): 0.198

Host Plug

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Merc

ury

Satu

ration, fr

action

(fre

quency)

<0.0025 0.0075 0.025 0.075 0.25 0.75 2.5 7.5 25 75 >100Pore Throat Radius, microns

PORE THROAT SIZE HISTOGRAM

0.0

0.1

0.2

0.3

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0.6

Merc

ury

Satu

ration, fr

action

(fre

quency)

<0.0025 0.0075 0.025 0.075 0.25 0.75 2.5 7.5 25 75 >100Pore Throat Radius, microns

PORE THROAT SIZE HISTOGRAM

MRIL T1 SPECTRA9515-9519 feet #172S

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12

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T1 Bins (ms)

Rela

tive

Ampl

itude

MRIL T1 SPECTRA9051-9055 feet #132S

0

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T1 Bins (ms)

Rela

tive

Ampl

itude

0.0

0.1

0.2

0.3

0.4

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0.6

Merc

ury

Satu

ration, fr

action

(fre

quency)

<0.0025 0.0075 0.025 0.075 0.25 0.75 2.5 7.5 25 75 >100Pore Throat Radius, microns

PORE THROAT SIZE HISTOGRAM

0.0

0.1

0.2

0.3

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0.5

0.6

Merc

ury

Satu

ration, fr

action

(fre

quency)

<0.0025 0.0075 0.025 0.075 0.25 0.75 2.5 7.5 25 75 >100Pore Throat Radius, microns

PORE THROAT SIZE HISTOGRAM

Sample: 172Sm Depth, feet: 9511.0 ambient 800psi 2000psi

Klinkenberg Permeability, md: 0.031 0.005 0.003Permeability to Air, md: 0.075 0.011 0.008

Swanson Permeability, md: 0.012 - -Porosity, fraction: 0.076 0.079 0.077

Host Plug Sample: 132Sm Depth, feet: 9048.65 ambient 800psi 2000psi

Klinkenberg Permeability, md: 0.805 0.443 0.338Permeability to Air, md: 1.15 0.512 0.394

Swanson Permeability, md: 0.636 - -Porosity, fraction: 0.103 0.107 0.104

Host Plug

Cum

ulat

ive

Poro

sity

(%)

Cum

ulat

ive

Poro

sity

(%)

SS Resistivity Model NMR ModelNMR Perm

NN

SS MATRIX

Shale Gas Models

Mancos Formation

Mancos Log Porosity

VCBWPHIT

Mancos Log Porosity

PHIE BVGXO

NMR T2 Distribution

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0.09

0.18

0.27

0.36

0.45

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T2 Relaxation Time (ms)

Incr

emen

tal P

oros

ity (%

)

0.0

2.0

4.0

6.0

8.0

10.0

Cum

ulat

ive

Poro

sity

(%)

Incremental

Cumulative

Mancos Core T2 Spectra

VCBW

VCBW

0

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1

1.2

1.4

1.6

Poro

sity

(%)

0.5 1 2 4 8 16 32 64 128 256 512 1024 2048

T2 Time (ms)

FED-9-12MRIL Data at 14724.5 feet

T2

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1.6

Poro

sity

(%)

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T1 Time (ms)

FED-9-12MRIL Data at 14724.5 feet

T1

Mancos LogT2 & T1Spectra

VCBW

GAS

BVWI

Shale Oil Source Rock NMR

0

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3

Poro

sity

(%)

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T2 Time (ms)

SERGEANT MAJORMRIL Data at 11101 feet PHI = 9.7%

T2

L-BakkenT2 & T1Spectra

VCBW BVWI

0

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1

1.5

2

2.5

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3.5

4

Poro

sity

(%)

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T1 Time (ms)

SERGEANT MAJORMRIL Data at 11101 feet PHI = 9.7%

T1

Lower Bakken Log Porosity

VCBWPHIT

Lower Bakken Log Porosity

BVWIEPHIE

R O C K Y M O U N T A I N S

1. For the Cretaceous sands evaluated in this study, clay conductivity is linearly related to VCBW

2. Analysis of Core and Log T1 and T2 data can yield values of PHIT, PHIE, VCBW, BVWI and Sgxo

3. VCBW relationships show why some shaly sand models are unstable in the Rocky Mountain area

4. Fresh State core analysis gives consistent porosity-permeability relationships that can be used in log transforms for TGS but not Shale Gas

5. NMR data give further insight into the physical properties of source rocks

CONCLUSIONS