Page 20 - Petrophysics

PREFACE THE FIRST EDITION
TO

This book presents the developed concepts, theories, and laboratory
procedures as related to the porous rock properties and their interactions with
fluids (gases, hydrocarbon liquids, and aqueous solutions). The properties of
porous subsurface rocks and the fluids they contain govern the rates of fluid flow
and the amounts of residual fluids that remain in the rocks after all economical
means of hydrocarbon production have been exhausted. It is estimated that the
residual hydrocarbons locked in place after primary and secondary production,
on a worldwide scale, is about 40% of the original volume in place. This
is a huge hydrocarbon resource target for refined reservoir characterization
(using the theories and procedures of petrophysics) to enhance the secondary
recovery or implement tertiary (EOR) recovery. The use of modern methods for
reservoir characterization with a combination of petrophysics and mathematical
modeling is bringing new life into many old reservoirs that are near the point of
abandonment. This book brings together the theories and procedures from the
scattered sources in the literature.
In order to establish the basis for the study of rock properties and rock-fluid
interactions, the first two chapters are devoted to a review of mineralogy,
petrology, and geology. Next, the two rock properties that are perhaps the
most important for petroleum engineering, i.e., porosity and permeability, are
presented in detail in Chapter 3. Finally, the problem of porosity-permeability
correlation has been solved. The subjects of Chapter 4 are the electrical resistivity
and water saturation of rocks which are the basis for well logging techniques.
The next chapter takes up the theories and applications of capillary pressure and
wettability to various phenomena associated with fluid-saturated rocks, such as
residual saturations due to fluid trapping, variations of relative permeabilities,
effects on production, and the measurements and use of capillary pressure for
determination of pore size distributions and wettability. Chapter 6 is devoted
exclusively to the applications of Darcy’s Law to linear, radial, laminar, and
turbulent flows, and multiple variations of permeability and porosity in rocks.
Chapter 7 presents an introduction to the important topic of rock mechanics
by considering rock deformation, compressibility, and the effects of stress
on porosity and permeability. The book ends with a discussion of rock-fluid
interactions associated with various types of formation damage. Finally, a set
of 19 laboratory procedures for determination of the rock and fluid properties,

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