Page 13 - Reservoir Geomechanics

xii Preface

The examples of regional stress fields from various regions around the world pre-
sented in Chapters 1 and 6 are taken from collaborative research done with former Ph.D.
students David Castillo, Lourdes Colmenares, Balz Grollimund and Martin Brudy.
This work, and much of the other work done with students and post-docs at Stan-
ford, was supported by the companies participating in the Stanford Rock and Borehole
Geophysics Consortium (SRB). Chapter 2,on pore pressure, refers to work done with
former Ph.D. students Thomas Finkbeiner, David Wiprut, Balz Grollimund and Alvin
Chan. The concepts in this chapter benefited from discussions with Peter Flemings
(Penn State) and Chris Ward. Chapter 3,on elasticity and constitutive laws, includes
a section on viscoelastic and viscoplastic constitutive laws for uncemented reservoir
sands that is based on research done in collaboration with former Ph.D. students Carl
Chang, Dan Moos and Paul Hagin. Chapter 4,on rock failure, was done in part in
collaboration with Lourdes Colmenares, former Ph.D. student John Townend, former
post-docs Chandong Chang and Lev Vernik and Dan Moos. James Byerlee (USGS
retired) was an inspirational Ph.D. advisor and teacher in rock mechanics. His work on
rock friction, discussed in Chapter 4,isof critical importance on establishing bounds
on stress magnitudes at depth in the crust. Chapter 5 is on fractures and faults at
depth, and is based largely on wellbore imaging studies initiated with former Ph.D.
student Colleen Barton and includes applications done with Thomas Finkbeiner and
Sneha Chanchani.
At the beginning of the second part of the book on Measuring Stress Orienta-
tion and Magnitude, Chapter 6 discusses stress concentrations around vertical wells
and compressional and tensional wellbore failures. This work was done in part in
collaboration with Dan Moos, Martin Brudy, David Wiprut and David Castillo, as
well as former post-docs Pavel Peska and Marek Jarosinski. John Healy and Steve
Hickman of the USGS were early collaborators on the use of hydraulic fracturing
for stress measurements. The stress measurement methods based on wellbore fail-
ures in vertical (Chapters 7) and deviated wellbores (Chapter 8) were developed in
collaboration with Pavel Peska, Martin Brudy and Dan Moos. Former Ph.D. student
Naomi Boness and I developed the methodologies presented in Chapter 8 for utiliz-
ing cross-dipole shear velocity logs for mapping stress orientation in deviated wells.
The techniques described in these chapters are not intended to be a comprehensive
review of the numerous techniques proposed over the years for stress measurement
(or stress estimation) at depth. Rather, I emphasize stress measurement techniques that
have proven to work reliably in deep wells under conditions commonly found in oil
and gas reservoirs. Chapter 9 reviews stress magnitude measurements made in vari-
ous sedimentary basins around the world in the context of global patterns of in situ
stress and some of the mechanisms responsible for intraplate stress. Chapter 9 also
includes a case study related to deriving stress magnitude information from geophysi-
cal logs carried out with former Ph.D. student Amie Lucier.
The final part of the book, Applications, starts with a discussion of wellbore stability
in Chapter 10. Many of the examples considered in the section are taken from studies