fesm talk sherif

8/12/2019 FESM Talk Sherif

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Sherif FaragPrincipal PetrophysicistSchlumberger

Integrated Workflow for natural fracture andporosity evaluation in granitic reservoirs

Based on SPE 123455 and SPWLA -2007-E

Acknowledgements

Aung Thanh Oo Bingjian Li Cholid Mas Le Van Hung (Lamson JOC) Marie Lefranc Michael Sanders Pierre-David Maizeret

Agenda

Overview Fractures for Petrophysicists

Aperture Apparent Permeability

Lithology for Petrophysicists Grain Density Intrusive events lithology boundaries

Discussion

Basement High

SPE 107141 An integrated Geology and Reservoir Engineering Approach for Modelling and HistoryMatching of a Vietnamese Fractured Granite Basement ReservoirSon Le Ngoc, PVN, Mahmoud Jamiolamady, Jean-Marie Questiaux, and Mehran Sohrabi, IPE-HWU


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Fractal Fractures: Production Capacity Fractal Fractures: Storage Capacity

Micro fractures and dissolution porosity

Fractal Fractures: Storage CapacityMicro Fracture Porosity

Lithology


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Lithology Typical Image Log in Fractured Basement

Interpretation Workflow:Step 1: Frac. Aperture from Images and Laterolog

Solution EnhancedFractures

Continuous Fractures Discontinuous

Fractures

New, semi-automatedfracture interpretationis also currentlyavailable

Fracture Aperture from Electrical Logs


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Fracture Aperture from Electrical Logs Fracture Aperture from Electrical Logs

Fracture Aperture from Electrical Logs Bad Borehole

Often the best fractured zones have the worst borehole Image logs may suffer

The solution is to fill the gaps using laterolog resistivity

Separation of deep and shallow resistivity is the most widelyused and works well in carbonates with some matrix porosityand fractures

Does not work as well in crystalline or metamorphic rock withno effective matrix porosity.


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Laterolog Operating Range Combined Laterolog and Induction Range



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Interpretation Workflow:Step 1: Frac. Aperture from FMI and Laterolog1 2 3 4 5 6 7

Interpretation Workflow:Step 1: Frac. Aperture from Images and Laterolog

Luthi, S.M., SouhaitP., Fracture Apertures from ElectricalBorehole Scans, Geophysics 55,1990, pp 821-833.

Faivre O., Fracture Evaluation From Quantitative AzimuthalResistivities, SPE 26434, 68th Annual Technical Conference andExhibition, Houston, Texas, October1993.

Shiomoto Y., Basement Reservoir Model Construction For RangDong Field,PetroVietnam technical forum2003.


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Stoneley Wave Stoneley Wave Attenuation

Stoneley Wave Attenuation: Fracture Aperture Stoneley Wave Attenuation: Fracture Aperture


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Stoneley Wave Attenuation: Fracture Aperture Stoneley Wave Attenuation: Fracture Aperture

Stoneley FractureExample

Good holeFast formationSeen on the FMI as a partiallyconductive fracture

Fracture detection from Stoneley

RX reflection Attenuation TX reflection

Occurs close to borehole wall

RC + TC = 1.0


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Dipole Wave Attenuation: Fracture Aperture Dipole Wave Attenuation: Fracture Aperture

Dipole Flexural Wave Attenuation Interpretation Workflow:Step 2: Sonic Stoneley & Dipole Attenuation

1 2 3 4 5 6 7 8


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Interpretation Workflow:Step 3: Process of Elimination

Calibratedmeasurement

Indicator Indicator Indicator Result

Sherlock Holmes: Once you eliminate the impossible,whatever remains, no matter how improbable, must be the truth. Sir Arthur Conan Doyle "A Scandalin Bohemia"

Interpretation Workflow:Step 3: Process of Elimination

1 2 3 4 5 6 7 8 9 10

Verification with PLT:Entry Points are Predicted, but not Rate

1 2 3 4 5 6 7

Verification with PLT:Entry Points are Predicted, but not Rate

758

670


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The largest fracture will have the highest apparent perm eability from logs.The most connected fracture will have the highest production rate.

FracturesBorehole

Plan view of vertical fractures with horizontal well Fracture Size, Density, Orientation

Fracture Size, Density, Orientation Fracture Size, Density, Orientation


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Fracture Orientation from image log

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Fracture Orientation from FMI:Side View Cartoon

Higher Fracture density and aperture30% of production

More variability in fracture dip, with highpermeability fractures more likely tointersect70% of production

Granite Outcrop: Lower Angle Fractures Model for Well Test Interpretation

Log-log Diagnostic plot of all Build-upPeriods using the Standard SuperpositionMethod

Height of the producing zone

Well

Fractured producing zone

0.1

1

10

100

1000

0.001 0.01 0.1 1 10 100 1000

ElapsedTime [hr]

P r e s s u r e

& L

o g - D e r

i v a t

i v e

[ p s i a ]

FP#5 Main BU

FP#6 Surface SI

FP#7 Surface SI

FP#8 Surface SI

FP#9 Surface SI

FP#10 Surface SI

Radial Flow

LinearFlow


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1

10

100

1000

0.001 0.01 0.1 1 10 100 1000

ElapsedTime [hr]

P r e s s u r e

& L o g - D e r

i v a t

i v e

[ p s i a ]

Deconvolved DataModel

4600

4650

4700

4750

4800

4850

4900

4950

5000

5050

5100

16-May 17-May 18-May 19-May 20-May 21-May 22-May 23-May 24-May 25-May

Date

P r e s s u r e

[ p i a ]

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

F l o w

R a

t e [ b p

d ]

Measured DataModelFowRate [bpd]

Well-Test ResultsProducing zone, h [m] 48

Porosity, [%] 2 %

Well radius, r w [in] 4.25

Reservoir Temperature, TR [ F]

264

Reservoir Pressure, PR [psia] 5063

Gas-Oil Ratio*, GOR [scf/stb] 100

Gas Gravity, g [air=1] 0.83Oil Density, o [ API] 46.1

Formation Volume Factor, Bo [rb/stb]

1.23

Viscosity, [cp] 1.38

Total compressibility, ct [/psi] 10-6

Model Result

Wellbore Storage, C [bbl/psi] 0.017

Skin, S 0.05

Fractures permeabil ity, k [md] 1420

Initial Reservoir Pressure atgauge depth, Pi [psia]

5050

Distance to first boundary, S[m]

601

Distance to second boundary,N [m]

565

Log-log Diagnostic Plot of Measured Data and Model for MainBuild-up Period

Entire Test History - Measured & Model Data

Lithology

Why is Lithology Important?

Porosity. With low porosity, matrix properties need to be accurate

Matrix density Neutron lithology response DT matrix

Dykes and lithology boundaries can create reservoircompartments

Different lithologies may be more prone to fracturing ordissolution Some operators have observed that felsic rocks are more

brittle, fracture more easily and feldspars are more reactiveand fractures are more prone to solution enhancement.

Lithology


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QAP Elemental Capture Spectroscopy

4 MeV neutron interactswith fomation:

Inelastic Interaction(multiple gamma-rays)

Slowing down of neutronthrough multiple scattering

Neutron Capture(multiple gamma-rays)

Gamma-Ray Spectrum

Energy [MeV]

0 1 2 3 4 5 6 7 8 9 10

C o u n

t s ( A r b

i t r a r y

S c a

l e )

Energy (MeV)

Fe

Ca

Si

S

Ti

Gd

0 1 2 3 4 5 6 7 8 9 100 1 2 3 4 5 6 7 8 9 10

C o u n

t s ( A r b

i t r a r y

S c a

l e )

Energy (MeV)

Fe

Ca

Si

S

Ti

Gd

1. Ba2. Ca3. Cl4. Cl BMF5. Fe

6. Gd7. H8. K9. S10. Si11. C r N i12. Ti13. Na14. Al15. Mg16. IC17. IO18. I Ca19. I Si20. ITool

Elemental weightconcentrations

Si,Ca,Fe,S,Ti

Elemental Capture Spectroscopy Discussion

Overview Fractures for Petrophysicists

Aperture Apparent Permeability

Lithology for Petrophysicists Grain Density Intrusive events lithology boundaries

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