CHALLENGEFind bypassed reserves in shale and carbonate formations adjacent to a conventional limestone reservoir.

SOLUTIONRun Platform Express* integrated wireline logging tool in combination with the ECS* elemental capture spectroscopy sonde to accurately determine clay content, mineralogy, and matrix properties to support robust, detailed petrophysical analysis.

RESULTSIdentified 150 ft of productive unconven-tional shale reservoir above the currently produced limestone and another 100 ft below it.

Looking beyond the conventional reservoir An operator’s target zone in the Midland basin is a conventional limestone bounded by shales. The reservoir varies from 100 to 150 ft in thickness and is produced from single-stage jobs designed to contain the stimulation. Because other wells in the area had mud logging shows, the operator wanted to know if additional producible formations were present.

Conducting fast, detailed petrophysical evaluation The ECS elementary capture spectroscopy sonde was combined with the Platform Express integrated wireline logging tool for one-run measurement to support petrophysical analysis. The Platform Express tool provides high-resolution resistivity, density, and microresistivity measurements. The ECS sonde measures relative elementary yields for the determination of lithology, porosity, permeability, and fluid saturations and their producibility.

Finding bypassed pay in unconventional reservoirsPetrophysical analysis found that the shales bounding the limestone reservoir are producible unconventional reservoirs, extending 150 ft above the limestone and 100 ft below it. The operator plans to reevaluate these bypassed reserves in completed wells and target them in new wells. The lithology from the ECS sonde’s measurements will be used to determine rock mechanical properties for stimulation design, including the identification of barriers to fracture propagation.

CASE STUDY

Formation Evaluation

Pairing the ECS elemental capture spectroscopy sonde with the Platform Express integrated toolstring provides high-resolution, comprehensive petrophysical data in one run.

ECS Spectroscopy Sonde’s Petrophysical Analysis Finds Additional 250 ft of Productive ShaleUnconventional reservoirs discovered above and below limestone reservoir to also be completed, Midland basin

Petrophysical analysis integrating measurements from the Platform Express tool and ECS spectroscopy found that the shales above and below the limestone reservoir total 250 ft of productive rock.

ThoriumConcentration

DensityStandoff

MeasuredDepth,

ft

DensityStandoff

Tension

in1 0

ECS CableSpeed

ft/h0 3,000

lbf2,000 6,000

Invaded Zone Resistivity

ohm.m0.2 2,000

SpectroLith Lithology

lbm/lbm1 0

Chlorite

lbm/lbm0 1

Fracture Gradient

psi/ft0.5 1

Poisson’s Ratio

0 0.5

Young’s Modulus

Fracture Gradientpsi/ft

Mpsi0 20

Total Porosity

Oil

Water

Water

Bound Water

Water Saturation

Oil or GasSaturation

Effective Porosity

Free Water

ft3/ft30.4 0

ELAN Total OrganicCarbon (TOC)

lbm/lbm0 0.25

TOC Terra

TOC

Oil or Gas

lbm/lbm0 0.25

TOC Schmoker

lbm/lbm0 0.25

Shale Permeability

Shale PermeabilitymD

TOC, wt%

mD1 1E–05

ELAN IntrisicPermeability

mD1,000 0.01

Water Permeability

mD1,000 0.01

Oil Permeability

mD1,000 0.01

Effective Porosity

ft3/ft30.4 0

Water

ft3/ft30.4 0

Absorbed Gas Oil in Placebbl/acre-ftft3/ft30 400

Oil in Place

bbl/acre-ft0 500

Oil in Place

Oil in Place

bbl/acre0 100,000

Total Gas scf/t

ft3/ft30 400

Free Gas in Place(GIP) bcf/section

Free Gas

GIP bcf/section

Free GIP

ft3/ft30 400

Absorbed GIP

ft3/ft30 400

Bound Water

ft3/ft30.4 0

Water Saturation

ft3/ft31 –1

Bulk Density Edited

North

FMI Image

g/cm32 3

Fe+

lbm/lbm0 0.25

Fe-

Fe - 1 Sigma

Moved Hydrocarbon

Water

Oil

Total Organic Carbon (TOC)

Dolomite

Calcite

Pyrite

Res

Res

Pay

Pay

Quartz

Bound Water

Illite

Chlorite

Moved Water

lbm/lbm0 0.25

Fe

lbm/lbm0 0.25

ELAN Minerology

V/V1 0

Pay

0

4

4

Res

0

Bulk Density Correction

g/cm3–0.05 0.45

Apparent Grain Density

g/cm3

Apparent Grain Densityg/cm3

2 3

ECS Matrix Density

g/cm32 3

R C

0 360

Neutron Porosity(Limestone)

ft3/ft30.4 –0.1

Sonic Porosity(Limestone)

ft3/ft30.4 –0.1

ft3/ft30.4 –0.1

Photoelectric Effect

Crossover

Density Porosity

0 10

Photoelectric Effect

Density Difference

Salt

Coal

Siderite

Anhydrite and Gypsum

Pyrite

Carbonate

Quartz-Feldspar-Mica

Clay

0 10

Array LaterologResistivity Mode 5

ohm.m 2,000

Array LaterologResistivity Mode 4

ohm.m 2,000

2,000

Array LaterologResistivity Mode 3

ohm.m

Array LaterologResistivity Mode 2

ohm.m0.2

0.2

0.2

0.2

2,000

True Formation Resistivity

ohm.m0.2 2,000

Gamma Ray (150–300)

Gamma Ray (150–300)

gAPI150 300

Gamma Ray (300–450)

Gamma Ray (300–450)

gAPI300 450

Gamma Ray (0–150)

gAPI0 150

Gamma Ray (450–600)

Gamma Ray (450–600)

Washout

Mudcake

gAPI450 600

Gamma Ray (600–750)

gAPI600 750

Gamma Ray (750–900)

gAPI750 900

Gamma Ray (900–1,050)

gAPI900 1,050

Rugosity

Rugosity

1/ft0 2

Bit Size

in6 16

Caliper

in6 16

ThoriumConcentration

DensityStandoff

MeasuredDepth,

ft

DensityStandoff

Tension

in1 0

ECS CableSpeed

ft/h0 3,000

lbf2,000 6,000

Invaded Zone Resistivity

ohm.m0.2 2,000

SpectroLith Lithology

lbm/lbm1 0

Chlorite

lbm/lbm0 1

Fracture Gradient

psi/ft0.5 1

Poisson’s Ratio

0 0.5

Young’s Modulus

Fracture Gradientpsi/ft

Mpsi0 20

Total Porosity

Oil

Water

Water

Bound Water

Water Saturation

Oil or GasSaturation

Effective Porosity

Free Water

ft3/ft30.4 0

ELAN Total OrganicCarbon (TOC)

lbm/lbm0 0.25

TOC Terra

TOC

Oil or Gas

lbm/lbm0 0.25

TOC Schmoker

lbm/lbm0 0.25

Shale Permeability

Shale PermeabilitymD

TOC, wt%

mD1 1E–05

ELAN IntrisicPermeability

mD1,000 0.01

Water Permeability

mD1,000 0.01

Oil Permeability

mD1,000 0.01

Effective Porosity

ft3/ft30.4 0

Water

ft3/ft30.4 0

Absorbed Gas Oil in Placebbl/acre-ftft3/ft30 400

Oil in Place

bbl/acre-ft0 500

Oil in Place

Oil in Place

bbl/acre0 100,000

Total Gas scf/t

ft3/ft30 400

Free Gas in Place(GIP) bcf/section

Free Gas

GIP bcf/section

Free GIP

ft3/ft30 400

Absorbed GIP

ft3/ft30 400

Bound Water

ft3/ft30.4 0

Water Saturation

ft3/ft31 –1

Bulk Density Edited

North

FMI Image

g/cm32 3

Fe+

lbm/lbm0 0.25

Fe-

Fe - 1 Sigma

Moved Hydrocarbon

Water

Oil

Total Organic Carbon (TOC)

Dolomite

Calcite

Pyrite

Res

Res

Pay

Pay

Quartz

Bound Water

Illite

Chlorite

Moved Water

lbm/lbm0 0.25

Fe

lbm/lbm0 0.25

ELAN Minerology

V/V1 0

Pay

0

4

4

Res

0

Bulk Density Correction

g/cm3–0.05 0.45

Apparent Grain Density

g/cm3

Apparent Grain Densityg/cm3

2 3

ECS Matrix Density

g/cm32 3

R C

0 360

Neutron Porosity(Limestone)

ft3/ft30.4 –0.1

Sonic Porosity(Limestone)

ft3/ft30.4 –0.1

ft3/ft30.4 –0.1

Photoelectric Effect

Crossover

Density Porosity

0 10

Photoelectric Effect

Density Difference

Salt

Coal

Siderite

Anhydrite and Gypsum

Pyrite

Carbonate

Quartz-Feldspar-Mica

Clay

0 10

Array LaterologResistivity Mode 5

ohm.m 2,000

Array LaterologResistivity Mode 4

ohm.m 2,000

2,000

Array LaterologResistivity Mode 3

ohm.m

Array LaterologResistivity Mode 2

ohm.m0.2

0.2

0.2

0.2

2,000

True Formation Resistivity

ohm.m0.2 2,000

Gamma Ray (150–300)

Gamma Ray (150–300)

gAPI150 300

Gamma Ray (300–450)

Gamma Ray (300–450)

gAPI300 450

Gamma Ray (0–150)

gAPI0 150

Gamma Ray (450–600)

Gamma Ray (450–600)

Washout

Mudcake

gAPI450 600

Gamma Ray (600–750)

gAPI600 750

Gamma Ray (750–900)

gAPI750 900

Gamma Ray (900–1,050)

gAPI900 1,050

Rugosity

Rugosity

1/ft0 2

Bit Size

in6 16

Caliper

in6 16

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*Mark of SchlumbergerOther company, product, and service names are the properties of their respective owners.Copyright © 2014 Schlumberger. All rights reserved. 11-FE-0111

CASE STUDY: ECS sonde’s petrophysical analysis finds net 250-ft shale reservoir, Midland basin

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