Page 9 - Applied Petroleum Geomechanics

xvi Preface

and rock mechanics knowledge, gives detailed applications of geomechanics
in the petroleum and related industries (e.g., other energy industries and
geological engineering), and provides a quick reference and guide in
geomechanics for engineers and geologists.
This book consists of 12 chapters. In Chapter 1 basic rock mechanics
concepts are introduced. Stressestrain governing equations are given for
both elastic and poroelastic rocks with consideration of thermal and
anisotropic effects. The in situ stress equations accounting for anisotropy
effect are derived.
Chapters 2 and 3 discuss rock physical and mechanical properties and
rock failure criteria. The anisotropy, stress-dependent behaviors, and fluid
impacts on rock properties are discussed. Empirical equations and new
correlations for obtaining rock properties are examined for both conven-
tional and unconventional reservoirs. Laboratory test methods and rock
failure criteria are discussed to reveal rock failure mechanisms.
Chapter 4 overviews basic rock fracture mechanics. Stress distributions
around the fracture tips in three fracture modes are introduced. Sneddon’s
solutions of fracture widths are examined, which can be applied to hy-
draulic fracturing modeling and wellbore strengthening design.
In Chapters 5 and 6, measurements and interpretations of horizontal
stresses are discussed. Integrated methods for calculating overburden stress
and the minimum and maximum horizontal stresses are examined in
different faulting stress regimes. Poisson’s ratioedependent stress polygons
are applied to constrain in situ stresses.
Chapters 7 and 8 cover pore pressure generation mechanisms and
overpressure behaviors. Pore pressure predictions in hydraulically con-
nected formations and in shales are systematically examined. Resistivity,
sonic, porosity, and d-exponent methods are modified using depth-
dependent normal compaction trends for easy applications. Methods and
procedures of real-time pore pressure detection are also presented.
In Chapter 9, fracture gradient prediction methods in sedimentary rocks
and salt are overviewed. Case applications are examined to illustrate how to
apply those methods. For depleted reservoirs, wellbore strengthening
techniques can be used to increase formation fracture gradient and reduce
mud losses in drilling operations. Semianalytical solutions for calculating the
fracture width are presented with consideration of in situ stress anisotropy.
Chapter 10 covers borehole failure types, wellbore stresses, and wellbore
stability. Elastic and poroelastic solutions are discussed for determining the
required mud weight for borehole stability. Impacts of bedding planes, rock