Page 121 - Principles of Applied Reservoir Simulation 2E

Chapter 12

Reservoir Structure

The physical size and shape of the reservoir may be inferred from several
methods that serve as sources of information for defining the large-scale
structure of the reservoir. These information sources are briefly reviewed below.

12.1 Giga Scale

Seismic measurements discussed in the literature by authors such as
Ausburn, et al. [ 1978], McQuillin, et al. [ 1984], Sheriff [ 1989] and Dorn [ 1998]
provide much of the Giga Scale information that can be directly used to
characterize a reservoir. Historically, seismic analyses have been of interest
primarily as a means of establishing the structural size of the reservoir. People
did not believe that seismic data could resolve sufficient detail to provide
information beyond overall reservoir structure. But that view has changed with
the emergence of 4-D seismic monitoring and reservoir geophysics [for example,
see Richardson, 1989;Ruijtenberg,etal., 1990; Anderson, 1995;He,etal., 1996;
Johnston, 1997;; Fanchi, et al. 1999]. It is therefore worthwhile to introduce
some basic geophysical concepts within the context of the reservoir management
function.
Seismic waves are vibrations that propagate from a source, such as an
explosion, through the earth until they encounter a reflecting surface and are
reflected into a detector, such as a geophone. Figure 12-1 shows a seismic trace.
Each trace represents the signal received by a detector. Changes to the amplitude

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