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Reservoir Geomechanics
In situ stress and rock mechanics applied to reservoir processes ��� ���������������������
Week 1 – Lecture 1 Course Overview
Mark D. Zoback Professor of Geophysics
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Why is Geomechanics Important?
Drilling and Reservoir Engineering • Compaction, Compaction Drive, Subsidence, Production-
Induced Faulting Prediction • Optimizing Drainage of Fractured Reservoirs
• Hydraulic Propagation in Vertical & Deviated Wells
• Wellbore Stability During Drilling (mud weights, drilling directions)
• Completion Engineering (long-term wellbore stability, sand production prediction)
• Well Placement (Azimuth and Deviation, Sidetracks)
• Underbalanced Drilling to Formation Damage
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Why is Geomechanics Important?
Reservoir Geology and Geophysics
• Optimizing Drainage of Fractured Reservoirs
• Pore Pressure Prediction
• Understanding Shear Velocity Anisotropy
• Fault Seal Integrity
• Hydrocarbon Migration
• Reservoir Compartmentalization
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Why is Geomechanics Important?
Exploitation of Shale Gas/Tight Gas/Tight Oil
• Properties of Ultra-Low Permeability Formations
• How Formation Properties Affect Production
• Optimizing Well Placement
• Multi-Stage Hydraulic Fracturing
• Importance of Fractures and Faults on Well Productivity
• Interpretation of Microseismic Data
• Simulating Production from Ultra-Low Permeability Formations
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Text for Class
Part I – Basic Principles Chapters 1-5
Part II – Measuring Stress Orientation and Magnitude
Chapters 6-9 Part III – Applications
Chapters 10-12
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Course Syllabus – Part I - Basic Principles
Week 1 Lecture 1 – Introduction and Course Overview Lecture 2 – Ch. 1 - The Tectonic Stress Field
HW-1 Calculating SV from density logs Week 2 Lecture 3 - Ch. 2 - Pore Pressure at Depth
HW-2 Estimating pore pressure from porosity logs Lecture 4 - Ch. 3 - Basic Constitutive Laws Week 3 Lecture 5 - Ch. 4 - Rock Strength
HW-3 Estimating rock strength from geophysical logs Lecture 6 - Ch. 4 - Fault Friction and Crustal Strength
HW-4 Calculating limits on crustal stress Week 4 Lecture 7 - Ch. 5 - Faults and Fractures
HW-5 Analysis of fractures in image logs Stanford|ONLINE gp202.class.stanford.edu
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Course Syllabus – Part II – In Situ Stress
Week 4 Lecture 8 - Ch. 6 - Stress Concentrations Around Vertical Wells Week 5 Lecture 9 - Ch. 7 - Hydraulic Fracturing, Measuring Shmin, Limiting Frac Height and Constraining Shmax
HW-6 Analysis of stress induced wellbore failures Lecture 10 - Ch. 8 - Failure of Deviated Wells Week 6 Lecture 11 - Ch. 9 - State of Stress in Sedimentary Basins
HW-7 Identification of critically-stressed faults
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Course Syllabus – Part III - Applications
Week 6 Lecture 12 - Ch. 10 - Wellbore Stability -1 Week 7 Lecture 13 - Ch. 10 - Wellbore Stability – 2 Lecture 14 - Ch. 11 - Critically-Stressed Faults and Flow
HW-8 Development of a geomechanical model Week 8 Lecture 15 - Ch. 11 - Fault Seal and Dynamic Hydrocarbon Migration Lecture 16 - Ch. 12 - Effects of Depletion, Reservoir Stress Paths Week 9 Lecture 17 - Ch. 12 - Compaction of Weak Sands and Shales and Subsidence
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Course Syllabus – Additional Topics
Week 9 Lecture 18 – Geomechanics and Shale Gas/Tight Oil Production - 1 Week 10 Lecture 19 – Geomechanics and Shale Gas/Tight Oil Production - 2 Lecture 20 - Geomechanics and Triggered Seismicity
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Exploration Appraisal Development Harvest Abandonment
Geomechanical Model
Time
Product ion
Wellbore Stability Pore Pressure Prediction
Sand Production Prediction
Compaction
Depletion
Subsidence Casing Shear
Fault Seal/Fracture Permeability
Fracture Stimulation/ Refrac Coupled Reservoir Simulation
Geomechanics Through the Life of a Field
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Components of a Geomechanical Model
Sv – Overburden SHmax – Maximum horizontal
principal stress Shmin – Minimum horizontal
principal stress
Sv
Shmin SHmax
Principal Stresses at Depth
UCS Pp Pp – Pore Pressure
UCS – Rock Strength (from logs) Fractures and Faults (from Image
Logs, Seismic, etc.)
Additional Components of a Geomechanical Model
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Course Syllabus – Part I - Basic Principles
Week 1 Lecture 1 – Introduction and Course Overview Lecture 2 – Ch. 1 - The Tectonic Stress Field
HW-1 Calculating SV from density logs Week 2 Lecture 3 - Ch. 2 - Pore Pressure at Depth
HW-2 Estimating pore pressure from porosity logs Lecture 4 - Ch. 3 - Basic Constitutive Laws Week 3 Lecture 5 - Ch. 4 - Rock Strength
HW-3 Estimating rock strength from geophysical logs Lecture 6 - Ch. 4 - Fault Friction and Crustal Strength
HW-4 Calculating limits on crustal stress Week 4 Lecture 7 - Ch. 5 - Faults and Fractures
HW-5 Analysis of fractures in image logs Stanford|ONLINE gp202.class.stanford.edu
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Anderson Classification of Relative Stress Magnitudes
Tectonic regimes are defined in terms of the relationship between the vertical stress (Sv) and two mutually perpendicular horizontal stresses (SHmax and Shmin)
Normal
Strike-slip
Reverse
Map View StereonetCross-section
SHmaxShmin
SHmaxShmin
SHmaxShmin
X
shmin
sv
b
sHmax
sv
a.
c .
b.
Sv > SHmax > Shmin
SHmax
Shmin
SvNormal
SHmax > Sv > Shmin
SHmax > Shmin > Sv
Strike-Slip
Reverse
SHmaxShmin
Sv
Shmin
SHmax
Sv
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Range of Stress Magnitudes at Depth
Hydrostatic Pp
Figure 1.4 a,b,c – pg.13
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Course Syllabus – Part I - Basic Principles
Week 1 Lecture 1 – Introduction and Course Overview Lecture 2 – Ch. 1 - The Tectonic Stress Field
HW-1 Calculating SV from density logs Week 2 Lecture 3 - Ch. 2 - Pore Pressure at Depth
HW-2 Estimating pore pressure from porosity logs Lecture 4 - Ch. 3 - Basic Constitutive Laws Week 3 Lecture 5 - Ch. 4 - Rock Strength
HW-3 Estimating rock strength from geophysical logs Lecture 6 - Ch. 4 - Fault Friction and Crustal Strength
HW-4 Calculating limits on crustal stress Week 4 Lecture 7 - Ch. 5 - Faults and Fractures
HW-5 Analysis of fractures in image logs Stanford|ONLINE gp202.class.stanford.edu
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Variations in Pore Pressure Within Compartments, Each With ~Hydrostatic Gradients
Figure 2.4 – pg.32 Stanford|ONLINE gp202.class.stanford.edu
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Range of Stress Magnitudes at Depth
Overpressure at Depth
Figure 1.4 d,e,f – pg.13
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Course Syllabus – Part I - Basic Principles
Week 1 Lecture 1 – Introduction and Course Overview Lecture 2 – Ch. 1 - The Tectonic Stress Field
HW-1 Calculating SV from density logs Week 2 Lecture 3 - Ch. 2 - Pore Pressure at Depth
HW-2 Estimating pore pressure from porosity logs Lecture 4 - Ch. 3 - Basic Constitutive Laws Week 3 Lecture 5 - Ch. 4 - Rock Strength
HW-3 Estimating rock strength from geophysical logs Lecture 6 - Ch. 4 - Fault Friction and Crustal Strength
HW-4 Calculating limits on crustal stress Week 4 Lecture 7 - Ch. 5 - Faults and Fractures
HW-5 Analysis of fractures in image logs Stanford|ONLINE gp202.class.stanford.edu
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Laboratory Testing
Stre
ss (M
Pa)
Figure 3.2 – pg.58 Stanford|ONLINE gp202.class.stanford.edu
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Constitutive Laws
Figure 3.1 a,b – pg.57 Stanford|ONLINE gp202.class.stanford.edu
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Figure 3.1 c,d – pg.57
Constitutive Laws
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Course Syllabus – Part I - Basic Principles
Week 1 Lecture 1 – Introduction and Course Overview Lecture 2 – Ch. 1 - The Tectonic Stress Field
HW-1 Calculating SV from density logs Week 2 Lecture 3 - Ch. 2 - Pore Pressure at Depth
HW-2 Estimating pore pressure from porosity logs Lecture 4 - Ch. 3 - Basic Constitutive Laws Week 3 Lecture 5 - Ch. 4 - Rock Strength
HW-3 Estimating rock strength from geophysical logs Lecture 6 - Ch. 4 - Fault Friction and Crustal Strength
HW-4 Calculating limits on crustal stress Week 4 Lecture 7 - Ch. 5 - Faults and Fractures
HW-5 Analysis of fractures in image logs Stanford|ONLINE gp202.class.stanford.edu
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Section 1 • Compressive Strength • Strength Criterion • Strength Anisotropy Section 2 • Shear Enhanced Compaction • Strength from Logs, HW 3 Section 3 • Tensile Strength • Hydraulic Fracture Propagation • Vertical Growth of Hydraulic Fractures Stanford|ONLINE gp202.class.stanford.edu
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Outline of Lecture
Course Syllabus – Part I - Basic Principles
Week 1 Lecture 1 – Introduction and Course Overview Lecture 2 – Ch. 1 - The Tectonic Stress Field
HW-1 Calculating SV from density logs Week 2 Lecture 3 - Ch. 2 - Pore Pressure at Depth
HW-2 Estimating pore pressure from porosity logs Lecture 4 - Ch. 3 - Basic Constitutive Laws Week 3 Lecture 5 - Ch. 4 - Rock Strength
HW-3 Estimating rock strength from geophysical logs Lecture 6 - Ch. 4 - Fault Friction and Crustal Strength
HW-4 Calculating limits on crustal stress Week 4 Lecture 7 - Ch. 5 - Faults and Fractures
HW-5 Analysis of fractures in image logs Stanford|ONLINE gp202.class.stanford.edu
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Limits on Stress Magnitudes Hydrostatic P
p
€
Sv −Pp
Shmin −Pp
= 3.1
Shmin =Sv −Pp
3.1+Pp
Shmin ≈ 0.6Sv
Critical Shmin
Critical SHmax
Critical SHmax
€
SHmax −Pp
Sv −Pp
= 3.1
SHmax = 3.1 Sv −Pp( ) +Pp
€
SHmax −Pp
Shmin −Pp
= 3.1
SHmax = 3.1 Shmin −Pp( ) +Pp
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Course Syllabus – Part I - Basic Principles
Week 1 Lecture 1 – Introduction and Course Overview Lecture 2 – Ch. 1 - The Tectonic Stress Field
HW-1 Calculating SV from density logs Week 2 Lecture 3 - Ch. 2 - Pore Pressure at Depth
HW-2 Estimating pore pressure from porosity logs Lecture 4 - Ch. 3 - Basic Constitutive Laws Week 3 Lecture 5 - Ch. 4 - Rock Strength
HW-3 Estimating rock strength from geophysical logs Lecture 6 - Ch. 4 - Fault Friction and Crustal Strength
HW-4 Calculating limits on crustal stress Week 4 Lecture 7 - Ch. 5 - Faults and Fractures
HW-5 Analysis of fractures in image logs Stanford|ONLINE gp202.class.stanford.edu
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Normal
Strike-slip
Reverse
Map View StereonetCross-section
SHmaxShmin
SHmaxShmin
SHmaxShmin
X
shmin
sv
b
sHmax
sv
a.
c .
b.
Sv > SHmax > Shmin
SHmax
Shmin
SvNormal
SHmax > Sv > Shmin
SHmax > Shmin > Sv
Strike-Slip
Reverse
SHmaxShmin
Sv
Shmin
SHmax
Sv
Stress Regimes and Active Fault Systems
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Course Syllabus – Part II – In Situ Stress
Week 4 Lecture 8 - Ch. 6 - Stress Concentrations Around Vertical Wells Week 5 Lecture 9 - Ch. 7 - Hydraulic Fracturing, Measuring Shmin, Limiting Frac Height and Constraining Shmax
HW-6 Analysis of stress induced wellbore failures Lecture 10 - Ch. 8 - Failure of Deviated Wells Week 6 Lecture 11 - Ch. 9 - State of Stress in Sedimentary Basins
HW-7 Identification of critically-stressed faults
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Stress Concentration Around a Vertical Well
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Compressional and Tensile Wellbore Failure
UBI Well A FMI Well B
Well A
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Course Syllabus – Part II – In Situ Stress
Week 4 Lecture 8 - Ch. 6 - Stress Concentrations Around Vertical Wells Week 5 Lecture 9 - Ch. 7 - Hydraulic Fracturing, Measuring Shmin, Limiting Frac Height and Constraining Shmax
HW-6 Analysis of stress induced wellbore failures Lecture 10 - Ch. 8 - Failure of Deviated Wells Week 6 Lecture 11 - Ch. 9 - State of Stress in Sedimentary Basins
HW-7 Identification of critically-stressed faults
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Drilling Induced Tensile Wall Fractures
FMI FMS Stanford|ONLINE gp202.class.stanford.edu
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Visund Field Orientations
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Regional Stress Field in the Timor Sea
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Complex Stress Field in the Elk Hills Field
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Horizontal Principal Stress Measurement Methods Stress Orientation
Stress-induced wellbore breakouts (Ch. 6) Stress-induced tensile wall fractures (Ch. 6) Hydraulic fracture orientations (Ch. 6)
Earthquake focal plane mechanisms (Ch. 5) Shear velocity anisotropy (Ch. 8)
Relative Stress Magnitude
Earthquake focal plane mechanisms (Ch. 5) Absolute Stress Magnitude
Hydraulic fracturing/Leak-off tests (Ch. 7) Modeling stress-induced wellbore breakouts (Ch. 7, 8) Modeling stress-induced tensile wall fractures (Ch. 7, 8)
Modeling breakout rotations due to slip on faults (Ch. 7)
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Horizontal Principal Stress Measurement Methods Stress Orientation
Stress-induced wellbore breakouts (Ch. 6) Stress-induced tensile wall fractures (Ch. 6) Hydraulic fracture orientations (Ch. 6)
Earthquake focal plane mechanisms (Ch. 5) Shear velocity anisotropy (Ch. 8)
Relative Stress Magnitude
Earthquake focal plane mechanisms (Ch. 5) Absolute Stress Magnitude
Hydraulic fracturing/Leak-off tests (Ch. 7) Modeling stress-induced wellbore breakouts (Ch. 7, 8) Modeling stress-induced tensile wall fractures (Ch. 7, 8)
Modeling breakout rotations due to slip on faults (Ch. 7)
Why do we use these techniques? 1. Model is developed using data from formations of interest 2. Every well that is drilled tests the model 3. They work!
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Obtaining a Comprehensive Geomechanical Model
Vertical stress S v z 0 ( ) = ρ g dz 0
z 0
∫ Shmin ⇐ LOT, XLOT, minifrac
Least principal stress
SHmax magnitude ⇐ modeling wellbore failures
Max. Horizontal Stress
Pore pressure Pp ⇐ Measure, sonic, seismic
Stress Orientation Orientation of Wellbore failures
Parameter Data
Rock Strength Lab, Logs, Modeling well failure Faults/Bedding
Planes Wellbore Imaging
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Course Syllabus – Part II – In Situ Stress
Week 4 Lecture 8 - Ch. 6 - Stress Concentrations Around Vertical Wells Week 5 Lecture 9 - Ch. 7 - Hydraulic Fracturing, Measuring Shmin, Limiting Frac Height and Constraining Shmax
HW-6 Analysis of stress induced wellbore failures Lecture 10 - Ch. 8 - Failure of Deviated Wells Week 6 Lecture 11 - Ch. 9 - State of Stress in Sedimentary Basins
HW-7 Identification of critically-stressed faults
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Wellbore Wall Stresses for Arbitrary Trajectories
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Course Syllabus – Part II – In Situ Stress
Week 4 Lecture 8 - Ch. 6 - Stress Concentrations Around Vertical Wells Week 5 Lecture 9 - Ch. 7 - Hydraulic Fracturing, Measuring Shmin, Limiting Frac Height and Constraining Shmax
HW-6 Analysis of stress induced wellbore failures Lecture 10 - Ch. 8 - Failure of Deviated Wells Week 6 Lecture 11 - Ch. 9 - State of Stress in Sedimentary Basins
HW-7 Identification of critically-stressed faults
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Generalized World Stress Map
180
180
270
270
0
0
90
90
180
180
-35 -35
0 0
35 35
70 70
SHmax incompressionaldomain
SHmax and Shminin strike-slipdomain
Shmin inextensionaldomain
9-2
M.L. Zoback (1992) and subsequent papers
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Course Syllabus – Part III - Applications
Week 6 Lecture 12 - Ch. 10 - Wellbore Stability -1 Week 7 Lecture 13 - Ch. 10 - Wellbore Stability – 2 Lecture 14 - Ch. 11 - Critically-Stressed Faults and Flow
HW-8 Development of a geomechanical model Week 8 Lecture 15 - Ch. 11 - Fault Seal and Dynamic Hydrocarbon Migration Lecture 16 - Ch. 12 - Effects of Depletion, Reservoir Stress Paths Week 9 Lecture 17 - Ch. 12 - Compaction of Weak Sands and Shales and Subsidence
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~5cm/yr
Critically-Stressed Faults and Fluid Flow
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Exploration Success Targeting Critically-Stressed Faults in
Damage Zones
Reservoir Faults &
Damage Zones Hennings et al (2012)
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a
d
h
k
j
a
k
h
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Course Syllabus – Part III - Applications
Week 6 Lecture 12 - Ch. 10 - Wellbore Stability -1 Week 7 Lecture 13 - Ch. 10 - Wellbore Stability – 2 Lecture 14 - Ch. 11 - Critically-Stressed Faults and Flow
HW-8 Development of a geomechanical model Week 8 Lecture 15 - Ch. 11 - Fault Seal and Dynamic Hydrocarbon Migration Lecture 16 - Ch. 12 - Effects of Depletion, Reservoir Stress Paths Week 9 Lecture 17 - Ch. 12 - Compaction of Weak Sands and Shales and Subsidence
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Depletion in Gulf of Mexico Field X
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Pp
S3
0
10
20
30
40
50
60
70
80
90
Feb-82
Nov-84
Aug-87
May-90
Jan-93
Oct-95
Jul-98
Apr-01
Jan-04
Pp (p
si)
Pp
S 3
Depletion in Gulf of Mexico Field X
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• Elliptical reservoir at 16300 ft depth with single well at centre • Reservoir dimensions – 6300 x 3150 x 70 ft, grid – 50 x 50 x 1 • Average permeability – 350 md, φinit – 30% • Oil flow, little/no water influx, no injection • IP – 10 MSTB/d, min. BHP - 1000 psi, Econ. Limit – 100 STB/d • Ran for maximum time of 8000 days
Compaction Drive
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Simulation Result - Recovery
0
5
10
15
20
25
30
0 2000 4000 6000 8000 10000
days
Cum
. O
il, M
MSTB
Elastic strain only (Constant compressibility)
Compaction drive
Compaction drive with permeability change
Compaction Drive
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National Geographic, October 2004
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Land Loss 1932-2050
Land Gain 1932-2050
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Oil and gas fields are pervasive
through the region of high rates of
land loss.
55
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Study Area
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )⎪⎩
⎪⎨
⎧
Δ−=
Δ−−=
∫
∫∞ −
∞ −
αααν
αααν
α
α
drJRJepHRCru
drJRJepHRCru
Dmr
Dmz
10 1
00 1
120,
120,
( ) ( )∫ Δ=ΔH
m dzzpzCH0
Assuming R>>H, total reduction in reservoir height:
For a circular reservoir, surface displacements are:
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Geertsma Model
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Geertsma Model
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Study Area: LaFourche Parish
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Leeville Subsidence
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Course Syllabus – Additional Topics
Week 9 Lecture 18 – Geomechanics and Shale Gas/Tight Oil Production - 1 Week 10 Lecture 19 – Geomechanics and Shale Gas/Tight Oil Production - 2 Lecture 20 - Geomechanics and Triggered Seismicity
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Palo Duro
Woodford
Avalon
Barnett 24-252 Tcf
Haynesville (Shreveport/Louisiana) 29-39 Tcf
Fayetteville 20 Tcf
Floyd/ Conasauga
Niobrara/Mowry
Cane Creek
Monterey
Michigan Basin
Utica Shale
Horton Bluff Formation
New Albany 86-160 Tcf
Marcellus 225-520 Tcf
Antrim 35-160 Tcf
Lewis/Mancos 97 Tcf
Green River 1.3-2 Trillion Bbl
Gammon
Colorado Group >300 Tcf
Bakken 3.65 Billion Bbl
Montney Deep Basin >250 Tcf
Horn River Basin/ Cordova Embayment >700 Tcf
0 600
MILES
Eagle Ford 25-100+ Tcfe
OIL SHALE PLAY
GAS SHALE PLAY
✓
✓
✓ ✓
✓
✓ ✓
Current Shale Gas/Tight Oil Research Projects
✓ ✓
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Eagle Ford Shale Pore Structure
50µm
10 µm 500 nm
Shale Permeability is a Million Times Smaller Than Conventional Reservoir
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Horizontal Drilling and Multi-Stage Slick-Water Hydraulic Fracturing Induces Microearthquakes (M ~ -1 to M~ -3)
To Create a Permeable Fracture Network
SHmax
Multi-Stage Hydraulic Fracturing
Dan Moos et al. SPE 145849
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Palo Duro
Woodford
Avalon
Barnett 24-252 Tcf
Haynesville (Shreveport/Louisiana) 29-39 Tcf
Fayetteville 20 Tcf
Floyd/ Conasauga
Niobrara/Mowry
Cane Creek
Monterey
Michigan Basin
Utica Shale
Horton Bluff Formation
New Albany 86-160 Tcf
Marcellus 225-520 Tcf
Antrim 35-160 Tcf
Lewis/Mancos 97 Tcf
Green River 1.3-2 Trillion Bbl
Gammon
Colorado Group >300 Tcf
Bakken 3.65 Billion Bbl
Montney Deep Basin >250 Tcf
Horn River Basin/ Cordova Embayment >700 Tcf
0 600
MILES
Eagle Ford 25-100+ Tcfe
OIL SHALE PLAY
GAS SHALE PLAY
We Need to Dramatically Improve Recovery Factors
Dry Gas ~25% Petroleum Liquids ~ 5% Stanford|ONLINE gp202.class.stanford.edu
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Course Syllabus – Additional Topics
Week 9 Lecture 18 – Geomechanics and Shale Gas/Tight Oil Production - 1 Week 10 Lecture 19 – Geomechanics and Shale Gas/Tight Oil Production - 2 Lecture 20 - Geomechanics and Triggered Seismicity
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Recent Publications Physical properties of shale reservoir rocks
Sone, H and Zoback, M.D. (2013), Mechanical properties of shale-gas reservoir rocks—Part 1: Static and dynamic elastic properties and anisotropy, Geophysics, v. 78, no. 5, D381-D392, 10.1190/GEO2013-0050.1
Sone, H and Zoback, M.D. (2013), Mechanical properties of shale-gas reservoir rocks—Part 2: Ductile creep, brittle strength, and their relation to the elastic modulus, Geophysics, v. 78, no. 5, D393-D402, 10.1190/GEO2013-0051.1
Slowly slipping faults during hydraulic fracturing
Das, I. and M.D Zoback (2013), Long-period, long-duration seismic events during hydraulic stimulation of shale and tight gas reservoirs — Part 1: Waveform characteristics, Geophysics, v.78, no.6, p. KS107–KS118.
Das, I., and M.D Zoback (2013), Long-period long-duration seismic events during hydraulic stimulation of shale and tight gas reservoirs — Part 2: Location and mechanisms, Journal of Geophysics, , v.78, no.6, p. KS97–KS105.
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Recent Publications Why slow slip occurs
Kohli, A. H. and M.D. Zoback (2013), Frictional properties of shale reservoir rocks, Journal of Geophysical Research, Solid Earth, v. 118, 1-17, doi: 10.1002/jgrb. 50346 Zoback, M.D., A. Kohli, I. Das and M. McClure, The importance of slow slip on faults during hydraulic fracturing of a shale gas reservoirs, SPE 155476, SPE Americas Unconventional Resources Conference held in Pittsburgh, PA, USA 5-7 June, 2012
Fluid transport/adsorption in nanoscale pores
Heller, R., J. Vermylen and M.D. Zoback (2013), Experimental Investigation of Matrix Permeability of Gas Shales, AAPG Bull., in press. Heller, R. and Zoback, M.D. (2013), Adsorption of Methane and Carbon Dioxide on Gas Shale and Pure Mineral Samples, The Jour. of Unconventional Oil and Gas Res., in review.
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Recent Publications . Viscoplasticity in clay-rich reservoirs
Sone, H. and M.D. Zoback (2013), Viscoplastic Deformation of Shale Gas Reservoir Rocks and Its Long-Term Effects on the In-Situ State of Stress, Intl. Jour. Rock Mech., in review. Sone, H and M.D. Zoback (2013), Viscous Relaxation Model for Predicting Least Principal Stress Magnitudes in Sedimentary Rocks, Jour. Petrol. Sci. Eng., in review.
Discrete Fracture Network Modeling in Unconventional Reservoirs
Johri, M. and M.D. Zoback, M.D. (2013), The Evolution of Stimulated Reservoir Volume During Hydraulic Stimulation of Shale Gas Formations, URTec 1575434, Unconventional Resources Technology Conference in Denver, CO, U.S.A., 12-14 August 2013
Case Studies Yang, Y. and Zoback, M.D., The Role of Preexisting Fractures and Faults During Multi-Stage Hydraulic Fracturing in the Bakken Formation, Interpretation, in press
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Course Syllabus – Additional Topics
Week 9 Lecture 18 – Geomechanics and Shale Gas/Tight Oil Production - 1 Week 10 Lecture 19 – Geomechanics and Shale Gas/Tight Oil Production - 2 Lecture 20 - Geomechanics and Triggered Seismicity
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An Increase in Intraplate Seismicity
Prague, OK* Nov. 2011 M 5.7
Prague, OK 3 M5+ Eqs Nov., 2011
Zoback (2012)
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An Increase in Intraplate Seismicity
Prague, OK* Nov. 2011 M 5.7
Prague, OK 3 M5+ Eqs Nov., 2011
Ellsworth (2013)
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Managing Triggered Seismicity
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EARTH April, 2012
Hurd and Zoback (2012)
Earthquakes Spreading Out Along an Active Fault
Horton (2012) Stanford|ONLINE gp202.class.stanford.edu
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- Avoid Injection into Potentially Active Faults - Limit Injection Rates (Pressure) Increases - Monitor Seismicity (As Appropriate) - Assess Risk - Be Prepared to Abandon Some Injection Wells
Seismicity Triggered by Injection
Guy Arkansas Earthquake Swarm
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