Page 7 - Fundamentals of Reservoir Engineering

PREFACE

This teaching textbook in Hydrocarbon Reservoir Engineering is based on various
lecture courses given by the author while employed in the Training Division of Shell
Internationale Petroleum Maatschappij B.V. (SIPM), in the Hague, between 1974 and
1977.

The primary aim of the book is to present the basic physics of reservoir engineering,
using the simplest and most straightforward of mathematical techniques. It is only
through having a complete understanding of the physics that the engineer can hope to
appreciate and solve complex reservoir engineering problems in a practical manner.

Chapters 1 through 4 serve as an introduction to the subject and contain material
presented on Shell's basic training courses. They should therefore be of interest to
anyone even remotely connected with the business of developing and producing
hydrocarbon reserves.

Chapters 5 through 8 are more specialised describing the theory and practice of well
testing and pressure analysis techniques, which are probably the most important
subjects in the whole of reservoir engineering. The approach is entirely general in
recognising that the superposition of dimensionless pressure, or pseudo pressure
functions, perm its the analysis of any rate-pressure-time record retrieved from a well
test, for any type of reservoir fluid. To appreciate this generality, the reader is advised
to make a cursory inspection of section 8.13 (page 295), before embarking on a more
thorough reading of these chapters. The author hopes that this will serve as a useful
introduction to the recently published and, as usual, excellent SPE Monograph
(Advances in Well Test Analysis; by Robert C. Earlougher, Jr.), in which a knowledge is
assumed of much of the theory presented in these four chapters.

Chapter 9 describes the art of aquifer modelling, while Chapter 10, the final chapter,
covers the subject of immiscible, incompressible displacement. The message here is-
that there is but one displacement theory, that of Buckley and Leverett. Everything else
is just a matter of "modifying" the relative permeability curves (known in the business
as "scientific adjustment"), to account for the manner in which the fluid saturations are
distributed in the dip-normal direction. These curves can then be used in conjunction
with the one dimensional Buckley-Leverett equation to calculate the oil recovery. By
stating the physics implicit in the generation of averaged (pseudo) relative
permeabilities and illustrating their role in numerical simulation, it is hoped that this
chapter will help to guide the hand of the scientific adjuster.

The book also contains numerous fully worked exercises which illustrate the theory.
The most notable omission, amongst the subjects covered, is the lack of any serious
discussion on the complexities of hydrocarbon phase behaviour. This has al ready
been made the subject of several specialist text books, most notably that of Amyx,
Bass and Whiting (reference 8, page 42), which is frequently referred to throughout this
text.