Page 38 - Applied Petroleum Geomechanics

CHAPTER 2

Rock physical and mechanical

properties

Contents

2.1 Rock density 30
2.1.1 Bulk and matrix densities 30
2.1.2 Bulk density at the shallow depth 33
2.2 Porosity 34
2.2.1 Porosity from density, velocity, and resistivity 34
2.2.2 Depth-dependent porosity and normal compaction 39
2.2.3 Stress-dependent porosity 39
2.3 Sonic or seismic velocities and transit time 41
2.3.1 Compressional and shear velocities 41
2.3.2 Sonic transit time 42
2.3.3 Relationship of V p and V s 42
2.3.4 Velocity and porosity relationship 44
2.3.5 Fluid (gas) effect on V p and V s 47
2.3.6 Anisotropy of V p and V s 49
2.4 Permeability 50
2.4.1 Permeability and hydraulic conductivity 50
2.4.2 The relationship of permeability and porosity 51
2.4.3 Stress-dependent permeability 52
2.4.4 Stress and permeability relations in fractured rocks 54
2.4.5 Stress and proppant effects on permeability of hydraulic fractures 57
2.4.6 Stress and permeability relation in porous rocks 59
2.5 Young’s modulus 60
2.5.1 Static Young’s modulus 61
2.5.2 Empirical equations to estimate static Young’s modulus 63
2.5.3 Anisotropic Young’s modulus 65
2.5.4 Dynamic Young’s modulus 66
2.5.5 Relations of dynamic and static Young’s moduli 67
2.6 Poisson’s ratio 70
2.6.1 Static Poisson’s ratio 70
2.6.2 Poisson’s ratio anisotropy 70
2.6.3 The relationship of dynamic and static Poisson’s ratios 72
2.7 Biot’s effective stress coefficient 73
2.7.1 Static Biot’s coefficient 73
2.7.2 Dynamic Biot’s coefficient 75

Applied Petroleum Geomechanics
ISBN 978-0-12-814814-3 Copyright © 2019 Elsevier Inc.
https://doi.org/10.1016/B978-0-12-814814-3.00002-2 All rights reserved. 29