Page 223 - Principles of Applied Reservoir Simulation 2E

Chapter 21

Model Initialization

The initial reservoir fluid saturation and pressure distributions are based
on data presented in this chapter. These distributions provide a volumetric
estimate of initial fluids in place that can be compared with basic reservoir
analysis of field performance. The basic reservoir analysis described below
includes a geologic estimate of volumetrics and a material balance determination
of initial fluids in place.

21.1 Volumetrics

A volumetric estimate of oil volume is a useful number for checking the
accuracy of the numerical representation of the reservoir in a reservoir model.
The volume of oil in the reservoir may be estimated as the product of bulk
volume Fj, porosity <j>, and oil saturation S 0.
The bulk volume of the reservoir is estimated by writing bulk volume V B
as the product A* A_yAz where A*, Ay, and Az approximate the length, width,
and net thickness of the pay interval, respectively.
4 From maps: A* = 2000' and A>> = 1200' for an area ~ 55 acres
1
4 From well logs: Az = 72' + 96 = 168'
3
The resulting estimate of bulk volume V B is 4.03 x 10 8 ft .
Pore Volume V P is the product §V B. Porosity (j) is estimated as the
thickness weighted average porosity from well logs:
* . 72 x Q.20 + 96 x Q.25 m
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