Applied Petroleum Geomechanics

Cover
Applied Petroleum Geomechanics
Copyright
Dedication
About the author
Foreword
Preface
1. Stresses and strains
	1.1 Stresses
		1.1.1 Normal and shear stresses
		1.1.2 Stress components
		1.1.3 Stresses in an inclined plane
		1.1.4 Principal stresses
		1.1.5 Effective stresses
		1.1.6 In situ stresses, far-field and near-field stresses
	1.2 Mohr's circle representation of stresses
		1.2.1 Mohr's circles for two-dimensional stresses
		1.2.2 Mohr's circles for three-dimensional stresses
	1.3 Strains
	1.4 Stress-strain relations in isotropic rocks
		1.4.1 Stress-strain relations for different rocks
		1.4.2 Isotropic dry rocks
		1.4.3 Isotropic thermal rocks
		1.4.4 Plane stress and plane strain in isotropic thermal rocks
			1.4.4.1 Plane stress state
			1.4.4.2 Plane strain state
		1.4.5 Isotropic porous rocks
	1.5 Stress-strain relations in anisotropic elastic rocks
		1.5.1 Orthotropic elastic rocks
		1.5.2 Transversely isotropic elastic rocks
	References
2. Rock physical and mechanical properties
	2.1 Rock density
		2.1.1 Bulk and matrix densities
		2.1.2 Bulk density at the shallow depth
	2.2 Porosity
		2.2.1 Porosity from density, velocity, and resistivity
		2.2.2 Depth-dependent porosity and normal compaction
		2.2.3 Stress-dependent porosity
	2.3 Sonic or seismic velocities and transit time
		2.3.1 Compressional and shear velocities
		2.3.2 Sonic transit time
		2.3.3 Relationship of Vp and Vs
		2.3.4 Velocity and porosity relationship
		2.3.5 Fluid (gas) effect on Vp and Vs
		2.3.6 Anisotropy of Vp and Vs
	2.4 Permeability
		2.4.1 Permeability and hydraulic conductivity
		2.4.2 The relationship of permeability and porosity
		2.4.3 Stress-dependent permeability
		2.4.4 Stress and permeability relations in fractured rocks
		2.4.5 Stress and proppant effects on permeability of hydraulic fractures
		2.4.6 Stress and permeability relation in porous rocks
	2.5 Young's modulus
		2.5.1 Static Young's modulus
		2.5.2 Empirical equations to estimate static Young's modulus
		2.5.3 Anisotropic Young’s modulus
		2.5.4 Dynamic Young's modulus
		2.5.5 Relations of dynamic and static Young's moduli
	2.6 Poisson's ratio
		2.6.1 Static Poisson's ratio
		2.6.2 Poisson's ratio anisotropy
		2.6.3 The relationship of dynamic and static Poisson's ratios
	2.7 Biot's effective stress coefficient
		2.7.1 Static Biot's coefficient
		2.7.2 Dynamic Biot's coefficient
		2.7.3 Empirical methods for Biot's coefficient
		2.7.4 Biot's coefficient estimate from well logs
	References
3. Rock strengths and rock failure criteria
	3.1 Laboratory tests for rock strengths
		3.1.1 Uniaxial tensile test
		3.1.2 Uniaxial compression test
		3.1.3 Triaxial compression test and rock peak strengths
		3.1.4 Polyaxial compression test
	3.2 Rock strengths from petrophysical and well log data
		3.2.1 Empirical equations of rock strengths in shales
			3.2.1.1 From sonic velocity
			3.2.1.2 From porosity
			3.2.1.3 From Young's modulus
		3.2.2 Empirical equations of rock strengths in sandstones
			3.2.2.1 From sonic velocity and transit time
			3.2.2.2 From Young's modulus and porosity
		3.2.3 Empirical equations of rock strengths in carbonate rocks
			3.2.3.1 From sonic velocity
			3.2.3.2 From Young's modulus and porosity
		3.2.4 Field methods for estimating rock uniaxial compressive strength
	3.3 Rock strength anisotropy
	3.4 Rock failure criteria
		3.4.1 Rock failure types
		3.4.2 Mohr-Coulomb failure criterion
			3.4.2.1 Linear Mohr-Coulomb failure criterion
			3.4.2.2 Modified Mohr-Coulomb failure criterion
		3.4.3 Weak plane sliding failure criterion
		3.4.4 Drucker-Prager failure criterion
		3.4.5 Modified Lade failure criterion
		3.4.6 Hoek-Brown failure criterion
		3.4.7 True triaxial failure criterion
		3.4.8 Cam-Clay failure criterion
		3.4.9 Tensile and Griffith failure criteria
	References
4. Basic rock fracture mechanics
	4.1 Stress concentration at the crack tip
	4.2 Linear-elastic fracture mechanics
		4.2.1 Griffith crack theory
		4.2.2 Stress intensity factor and fracture toughness
		4.2.3 Three basic fracture modes
		4.2.4 Fracture tip stresses and displacements
			4.2.4.1 Model I fracture
			4.2.4.2 Model II fracture
			4.2.4.3 Model III fracture
		4.2.5 Stresses and displacements in an inclined fracture
		4.2.6 Plastic zone and fracture process zone at the fracture tip
			4.2.6.1 Plastic process zone at the fracture tip
			4.2.6.2 Fracture process zone at the fracture tip in rock
		4.2.7 Fracture toughness of rock and its correlation to tensile strength
	4.3 Sneddon solutions of fracture widths
		4.3.1 2-D plane strain solution of the Griffith fracture
		4.3.2 General solution for fracture width of the Griffith fracture
		4.3.3 3-D solution for a penny-shaped fracture
	4.4 Natural fractures and mechanical behaviors of discontinuities
		4.4.1 Discontinuities and discrete fracture network
		4.4.2 Mechanical behaviors of discontinuities
		4.4.3 Mechanical behaviors of rock masses
	References
5. In situ stress regimes with lithology-dependent and depletion effects
	5.1 In situ stresses in various faulting regimes
	5.2 In situ stress bounds and stress polygons
	5.3 Lithology-dependent in situ stresses and improved stress polygon
		5.3.1 Lithology-dependent coefficient of friction of the fault
		5.3.2 Poisson's ratio-dependent stress polygon
		5.3.3 Relationship of the coefficient of friction of the fault and Poisson's ratio
		5.3.4 Lithology-dependent minimum and maximum horizontal stresses
	5.4 Fault strength and in situ stresses
	5.5 Depletion and injection impacts
		5.5.1 Depletion-reducing horizontal stresses
		5.5.2 Depletion and Mohr's circle representation
		5.5.3 Injection and shear failures
	References
6. In situ stress estimate
	6.1 Overburden stress
		6.1.1 Overburden stress from bulk density
		6.1.2 Overburden stress from empirical equations
			6.1.2.1 Overburden stress for offshore drilling
			6.1.2.2 Overburden stress for onshore drilling
	6.2 Minimum horizontal stress from measurements
		6.2.1 Leak-off tests in normal and strike-slip faulting stress regimes
		6.2.2 Leak-off tests in the reverse faulting stress regime
		6.2.3 Minimum stress interpretations from leak-off tests
		6.2.4 Minimum stress from diagnostic fracture injection test
		6.2.5 Case example of in situ minimum stress measurement
	6.3 Minimum horizontal stress calculation
		6.3.1 Minimum horizontal stress without tectonic impact
		6.3.2 Minimum horizontal stress with tectonic impact
		6.3.3 Minimum horizontal stress in anisotropic rocks
		6.3.4 Minimum horizontal stress from empirical equations
	6.4 Maximum horizontal stress
		6.4.1 Maximum horizontal stress from extended leak-off test
			6.4.1.1 No fluid penetration in the formation
			6.4.1.2 For permeable fractures
		6.4.2 Maximum horizontal stress from drilling-induced tensile fractures
			6.4.2.1 In normal and strike-slip faulting stress regimes
			6.4.2.2 In the reverse faulting stress regime
				6.4.2.2.1 For a vertical well
				6.4.2.2.2 For a horizontal well
		6.4.3 Maximum horizontal stress from wellbore breakouts
		6.4.4 Maximum horizontal stress from breakouts and drilling-induced fractures
		6.4.5 Maximum horizontal stress from excess horizontal strains
		6.4.6 Maximum horizontal stress from equilibrium of in situ stresses and pore pressure
		6.4.7 Maximum horizontal stress estimate
	6.5 Maximum horizontal stress orientation
		6.5.1 From borehole breakouts
		6.5.2 From drilling-induced tensile fractures
	References
7. Abnormal pore pressure mechanisms
	7.1 Normal and abnormal pore pressures
		7.1.1 Hydrostatic pressure and normal pore pressure
		7.1.2 Salinity effect on hydrostatic pressure
		7.1.3 Overpressure and underpressure
		7.1.4 Pore pressure and pore pressure gradient
	7.2 Origins of abnormal pore pressures
		7.2.1 Overpressures by compaction disequilibrium
		7.2.2 Overpressures from hydrocarbon generation
		7.2.3 Overpressures by uplift and unloading
	7.3 Overpressures and smectite-illite transformation
		7.3.1 Overpressure mechanism of smectite to illite transformation
		7.3.2 Smectite and illite transition identified by rock properties
		7.3.3 Unloading caused by smectite and illite transformation
		7.3.4 Smectite and illite normal compaction trend and overpressure
	7.4 Pore pressure seals and compartments
	7.5 Abnormal formation pressures in some petroleum basins
		7.5.1 Global distribution
		7.5.2 Abnormal pressure in the Macondo well of the Gulf of Mexico
		7.5.3 Abnormal pressures in the Scotian Shelf, Canada
		7.5.4 Abnormal pressures in the Central Graben, the North Sea
		7.5.5 Abnormal pressures in the Cooper Basin, Australia
		7.5.6 Abnormal pressures in China
		7.5.7 Abnormal pressures in the Malay Basin
		7.5.8 Abnormal formation pressures in major US shale plays
			7.5.8.1 Pore Pressure Gradient in Major US Shale Plays
			7.5.8.2 Bakken and Three Forks plays
			7.5.8.3 Haynesville and Bossier shale plays
	References
8. Pore pressure prediction and monitoring
	8.1 Introduction
	8.2 Pore pressure prediction from hydraulics
		8.2.1 Pore pressure in a hydraulically connected formation
		8.2.2 Shallow gas flow and pore pressure elevation by gas columns
		8.2.3 Centroid effect
		8.2.4 Vertical and lateral transfer and drainage
	8.3 Principle of pore pressure prediction for shales
	8.4 Pore pressure prediction from porosity
		8.4.1 Depth-dependent porosity method
		8.4.2 Case application of the porosity method
	8.5 Pore pressure prediction from resistivity
		8.5.1 Eaton's resistivity method
		8.5.2 Modified Eaton's resistivity method
		8.5.3 From Archie's resistivity equation
		8.5.4 Resistivity corrections from temperature and salinity
	8.6 Pore pressure prediction from velocity and transit time
		8.6.1 Eaton's method and its improvement
			8.6.1.1 Eaton's method
			8.6.1.2 Modified Eaton's method
		8.6.2 Bowers' method
		8.6.3 Miller's method
		8.6.4 Tau model
		8.6.5 Depth-dependent sonic method
		8.6.6 Distinguishing gas effect on compressional transit time
		8.6.7 Smectite and illite impacts on pore pressure prediction
	8.7 Predrill pore pressure prediction and calibration
		8.7.1 Calibration from formation pressure tests
		8.7.2 Calibration from well influx, kick, and connection gas
		8.7.3 Calibration from wellbore instability events
		8.7.4 Predrill pore pressure prediction in the prospect well
			8.7.4.1 From seismic interval velocity
			8.7.4.2 From analog wells
	8.8 Real-time pore pressure detection
		8.8.1 Procedures of real-time pore pressure detections
		8.8.2 Real-time pore pressure detection-resistivity and sonic methods
		8.8.3 Real-time pore pressure detection-corrected d-exponent method
		8.8.4 Real-time pore pressure detection-from connection gas or total gas
		8.8.5 Abnormal pore pressure indicators and detections in real-time drilling
			8.8.5.1 Indicators from logging-while-drilling logs
			8.8.5.2 Direct indicators of pore pressure-well influxes and mud losses
			8.8.5.3 Indicators from mud gas
		8.8.6 Abnormal pore pressure interpretation from wellbore instability
			8.8.6.1 Indicators from wellbore failures
			8.8.6.2 Indicators from abnormal cuttings
		8.8.7 Summary of real-time indicators for abnormal pore pressures
	Appendix 8.1. Derivation of pore pressure prediction from porosity
	Appendix 8.2. Derivation of sonic normal compaction equation
	References
9. Fracture gradient prediction and wellbore strengthening
	9.1 Fracture gradient in drilling operations
		9.1.1 Concept of fracture gradient
		9.1.2 Fracture gradient from leak-off tests
		9.1.3 Fracture gradient and mud losses in drilling operations
	9.2 Fracture gradient prediction methods
		9.2.1 Matthews and Kelly method
		9.2.2 Depth-dependent k0 method
		9.2.3 Eaton's method or the minimum stress method
		9.2.4 Daines' method
		9.2.5 Fracture gradient from wellbore tensile failure
	9.3 Drilling direction impacts on fracture gradient in horizontal wells
	9.4 Temperature and depletion impacts on fracture gradient
		9.4.1 Temperature impact on fracture gradient
		9.4.2 Pore pressure and depletion impacts on fracture gradient
	9.5 Upper and lower bound fracture gradients
	9.6 Fracture gradient in salt and subsalt formations
	9.7 Reasons of leak-off test being greater than overburden stress gradient
		9.7.1 Leak-off test value being the formation breakdown pressure
		9.7.2 In tectonic stress regimes
	9.8 Wellbore strengthening to increase fracture gradient
		9.8.1 Wellbore strengthening
		9.8.2 Analytical solutions of the fracture width
		9.8.3 Semianalytical solution of the fracture width accounting for stress anisotropy
		9.8.4 Fracture width impacted by inclinations and drilling directions
		9.8.5 Fracture widths in the stress cage with consideration of temperature
		9.8.6 3-D semianalytical solution of the fracture width
	References
10. Borehole stability
	10.1 Wellbore instability and mud weight window
	10.2 Borehole failure types and identification
		10.2.1 Wellbore breakouts and drilling-induced tensile fractures
		10.2.2 Borehole breakout diagnosis from caliper logs
		10.2.3 Breakouts and drilling-induced tensile fractures from image logs
		10.2.4 Borehole stability and lithology
		10.2.5 Borehole instability diagnosis from cuttings
	10.3 Wellbore stability-elastic solutions for inclined boreholes
		10.3.1 Local far-field stresses in an inclined borehole
		10.3.2 Near-wellbore stresses in an inclined borehole
		10.3.3 Principal effective stresses at the wellbore wall
		10.3.4 Minimum mud weight calculation using the Mohr-Coulomb failure criterion
		10.3.5 Minimum mud weight calculation using modified Lade failure criterion
	10.4 Wellbore stability-elastic solutions for vertical boreholes
		10.4.1 Near-wellbore stresses in a vertical borehole
		10.4.2 Minimum mud weight calculation using the Mohr-Coulomb failure criterion
			10.4.2.1 For the maximum tangential stress is the maximum principal stress
			10.4.2.2 For the maximum axial stress is the maximum principal stress
	10.5 Required mud weight for borehole stability with allowable breakout width
	10.6 Wellbore breakout profiles
		10.6.1 Rock strength effect on wellbore breakouts
		10.6.2 Horizontal stress effect on wellbore breakouts
		10.6.3 Mud weight effect on wellbore breakouts
		10.6.4 Breakouts in the horizontal well
	10.7 Single-porosity poroelastic wellbore stability solutions
		10.7.1 Single-porosity poroelastic wellbore solution
		10.7.2 Steady state poroelastic wellbore solution
	10.8 Dual-porosity finite element wellbore stability solutions
		10.8.1 Wellbore stresses in elastic, single-, and double-porosity media
		10.8.2 Wellbore failures in a strike-slip faulting stress regime
			10.8.2.1 Inclined boreholes
			10.8.2.2 Horizontal wells
		10.8.3 Wellbore failures in a normal faulting stress regime
	10.9 Wellbore tensile failures
		10.9.1 Elastic solution of wellbore tensile failures
		10.9.2 Poroelastic solution of wellbore tensile failures
	10.10 Borehole stability analysis with consideration of weak bedding planes
		10.10.1 Shear failure in weak bedding planes in vertical and horizontal wells
		10.10.2 Shear failure of weak bedding planes in an inclined borehole
		10.10.3 Illustrative examples
	10.11 Borehole stability in difficult conditions
		10.11.1 Borehole stability in fractured formations
		10.11.2 Time effect on borehole stability
		10.11.3 Chemical effect on borehole stability
		10.11.4 Borehole stability in salt and subsalt formations
			10.11.4.1 Salt creep modeling
			10.11.4.2 Mud weight design in salt formation
			10.11.4.3 Case study of borehole stability in subsalt formations
	References
11. Geomechanics applications in hydraulic fracturing
	11.1 Fracture initiation and formation breakdown pressures
		11.1.1 Fracture initiation pressure
		11.1.2 Formation breakdown pressure
		11.1.3 Fracture propagation pressure
	11.2 In situ stresses controlling fracture propagation
		11.2.1 In situ stress regimes and hydraulic fracture propagation
		11.2.2 Stress barrier and hydraulic fracture containment
		11.2.3 Rock properties and heterogeneities on hydraulic fracture propagation
		11.2.4 Stress difference and hydraulic fracture propagation
	11.3 Impact of shear stresses on fracture propagations
		11.3.1 Shear stress and fracture kinking
		11.3.2 Shear stress and hydraulic fracture propagation
		11.3.3 Off-azimuth and on-azimuth horizontal wells
	11.4 Impact of depletion on hydraulic fracturing propagation
	11.5 Stress shadow and fracture interference
		11.5.1 Stress shadow and spacing of stages
		11.5.2 3-D conceptual model of stress shadow impact
	11.6 Interaction of hydraulic fractures and natural fractures
	11.7 Rock brittleness
	11.8 PKN and GDK models of hydraulic fracturing
		11.8.1 PKN model and calculation of fracture dimensions
			11.8.1.1 PKN model and its modification
			11.8.1.2 Simple calculation of hydraulic fracture dimensions
		11.8.2 KGD model
	References
12. Sanding prediction
	12.1 Elastic solutions for sanding prediction
		12.1.1 Sand arch stability
		12.1.2 Open hole wellbore stability
		12.1.3 Elastic solution on perforation tunnel stability
	12.2 Poroelastic solutions for sanding prediction
		12.2.1 Critical drawdown in an open hole or perforation tunnel
		12.2.2 Case application for sanding prediction
	12.3 Sanding failure criteria and sanding prediction
		12.3.1 Sanding failure criteria
		12.3.2 Sanding strength and critical drawdown
	References
Index
	A
	B
	C
	D
	E
	F
	G
	H
	I
	K
	L
	M
	N
	O
	P
	R
	S
	T
	U
	V
	W
	X
	Y
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