Page 167 - Principles of Applied Reservoir Simulation 2E

152 Principles of Applied Reservoir Simulation

much on the coding of the simulator as it does on the formulation technique. The
best way to determine simulator robustness is to test the simulator with data sets
representing many different types of reservoir management problems. The
examples provided with WINB4D are designed to demonstrate the robustness,
or range of applicability, of the simulator.
Simulator technology is generally considered proprietary technology, yet
it has an economic impact that takes it out of the realm of the research laboratory
and makes it a topic of importance in the corporate boardroom. Nevertheless,
numerical representations of nature are subject to inaccuracies [for example, see
Mattax and Dalton, 1990; Saleri, 1993; and Oreskes, et al., 1994]. This point
has been illustrated in several simulator comparison projects sponsored by the
Society of Petroleum Engineers beginning with Odeh [1981] and continuing
through Killough [1995]. Each comparison project was designed to allow
comparisons of proprietary technology by asking participating organizations to
solve the same pre-determined problem. Figure 15-3 is taken from the first
comparison project [Odeh, 1981]. The first project compared the performance
of simulators modeling the injection of gas into a saturated black oil reservoir.
Figure 15-3 shows that differences in the formulations of several reservoir
simulators lead to differences in predictions of economically important quantities
such as oil rate production.

O

4 6 8 10
Time, years
Figure 15-3. Oil rate from first SPE comparative
solution project (after Odeh, 1981; reprinted by
permission of the Society of Petroleum Engineers).