bakken and three forks logging acquisition for reservoir...
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Schlumberger Public
Bakken and Three Forks Logging Acquisition for Reservoir Characterization and Completion Optimization
Ernest Gomez ([email protected]), Peter Hook, Peter S. Kaufman and Stephen D. Sturm
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Acknowledgements
• Bakken Consortium Members
– XTO (Headington)– Brigham– Continental – Encore– Hess– Petro-Hunt– Whiting
• Schlumberger
• North Dakota Oil and Gas Research Council
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Outline
• Takeaways
• Target Identification– Fractures
– Lithology
– Porosity and permeability
• Stimulation Optimization– Rock properties
• Recommendations/Summary
Qtz
Ls
Dol
Illite
Fld
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Takeaways• Bakken and Three Forks
properties are variable:– Lithology
– Fractures
– Matrix
– 3-D rock mechanical
• Measurement of these properties is important and can be used for:
– Target identification
– Model and optimize completions
XTONesson State 42-36X
(Three Forks)
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Role of Core
• Serves as calibration for logging suites
– Lithology (XRD)
– Petrophysical properties (Ф, k and Sw)
– Anisotropic mechanical rock properties (YM, PR, UCS, stress)
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Target Identification
• Fractures
• Lithology
• Matrix– Porosity
– Permeability Qtz
Ls
Dol
Illite
Fld
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FMI (Fullbore Formation MicroImager)Fracture CharacterizationHorizontal Well• Fracture orientation, density, aperture
and spacing • Identification of fracture swarms for
completion design• Multi-axis caliper for swell packer
design• Identify lateral lithology variations
• Stratigraphic, structure and stress azimuth information
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FMI - Nesson State 44X-36
Fractures• Natural fractures sparse• Occur In limestones (ELAN –
ECS) and zones of higher curvature
• Fracture permeability: microdarcy - nanodarcy
• Fracture porosity: 0.004% net phi
• Induced fractures
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ECS (Elemental Capture Spectroscopy Sonde)Lithology
Vertical and Horizontal Well• Lateral target selection – used
in ELAN for pay evaluation• Carbonate/Clastic lithology
identification
• Clay volume
• Improved lithology - better mechanical properties and improved frac design
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ECS – Nesson State 42X-36
UpperBakken
MiddleBakken
LowerBakken
Al Si Ca SFe
GR
ThreeForks
Clay
Clastic Carbonate
Pyrite
Lithology
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CMR (Combinable Magnetic Resonance)Porosity and Permeability
Vertical Well• Lithology independent porosity
and permeability• Horizontal placement - used with
ELAN for complete pay evaluation
• Combinable with other logging tools – lower rig costs
• Good resolution of laminated sediments (Three Forks)
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CMR - Porosity Definitions
T2 Distribution - Main output of CMRT20.3ms 3.0ms 33ms
CMFF (%)CMRP_3MS (%)
TCMR (%)
LOG_T2CUTOFF
3000ms
T2 Distribution0.3ms 3000ms
Three porosity measurements give an indication of the
types of porosity which are present.
CapillaryBound
Porosity
Small PorePorosity
Free FluidPorosity (Producible
Fluids)Total Porosity Area
under Distribution
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CMR – Nesson State 42X-36 (Vertical)
LowerBakken
UpperBakken
MiddleBakken
ThreeForks
GRФ k10% 1 mD
Middle Bakken• Best Ф and k
developed in dolomitic sediments
• Decrease in Ф and k toward base
Three Forks• Best Ф and k developed
in laminated sediments (dolomite and mudstone) at top
• In general better Ф and k than Bakken; more dolomite
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Lithology and Matrix Results - Nesson State 42X-36Ф k
FldQtz
Ls
Dol
Illite
Dol
LowerBakken
UpperBakken
MiddleBakken
ThreeForks
• Detailed lithology (ELAN) tied to core and ECS• Porosity and permeability tied to core and CMR
Lithology(Dry Weight %) 30%
10 mD0.010%
Pyr
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• Provides low cost way of acquiring information in laterals
• Pumped down inside drill pipe
• When calibrated to core and vertical logs from pilot well can be used to determine:
– Lithology
– Porosity (reserves)
• Used in hydraulic fracture stage selection or swell packer placement
Clay
Quartz Porosity
Calcite
Reservoir Saturation Tool (RST)(Reservoir Characterization)
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Stimulation Optimization
• Mechanical Rock Properties– Containment
– Planning
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Sonic Scanner(3-D Rock Mechanical Properties)
• Stress orientation (SH)
• Stress magnitude
• Anisotropic mechanical rock properties
– Young’s Modulus
– Poisson’s Ratio
• Input for hydraulic fracture modeling and optimization
TOC
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Sonic Scanner - 3-D Rock Mechanics
Large stress difference due
to shale layering
Young’s Modulus and PR differ by
80%
In this well hydraulicfracture containment
provided byBakken Shales
0.73/0.81
0.73/0.73
0.73/0.89
Upper Bakken
MiddleBakken
LowerBakken
ThreeForks
Young’sModulus PR
AnisoStress
GR
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Multi Stage – Nesson State 44X-3610
900
1150
0
1315
0
Fractures
TXSP Aniso
% Carbonate
GR
1125
0
1220
0
1250
0
1345
0
1380
0
Stage 1Stage 6 Stage 5 Stage 4 Stage 3 Stage 2
PackerIn Target Perforations
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Recommended Logging Suite - Vertical
• Vertical Pilot (first 1 to 2 wells in an area)
– PEx (Resistivity and Porosity)
– ECS (Lithology)
– CMR (Porosity and Permeability)
– RST (Reservoir Characterization)
– Sonic Scanner (SH and Vertical Hydraulic Fracture Containment)
– Core
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Recommended Logging Suite - Laterals
• Lateral (first 1 to 2 wells in an area)
– FMI (Fracture Characterization)
– ECS – Sonic Scanner– RST
• Lateral (Development)– RST
MD
TVD
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Summary• Core calibrated log measurements in the Bakken
and Three Forks can lead to a better understanding of :
– Fractures– Porosity– Permeability– Lithology– Anisotropic mechanical rock properties and
stress profile • These log measurements can be used to model
and optimize stimulations