Simulating Heterogeneity in Reservoir Models Through Statistically Defined Pseudowells

M. P. Ryan, T. A Jones, C. R. Johnson

In computer modeling of heterogeneous reservoirs, it is often necessary to introduce stochastic variation to simulate inferred features of depositional environments. In Exxon's three-dimensional modeling program, we found that statistically defined pseudowells are a simple, direct, and effective method to introduce inferred heterogeneity.

The pseudowells are based on the attributes of the real wells, with the number and location of the pseudowells governing the size and distribution of the heterogeneities in the final model. Occurrence and thickness of a specific lithofacies within a pseudowell are controlled by user-defined transition probabilities and thickness distributions calculated from well data or interpreted by the geologist. Shape and orientation of heterogeneous features are controlled by the distribution of pseudowell locations and by interpolation bias within the modeling program itself.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.