An Efficient Semianalytic Reservoir Model for Complex Reservoirs

Abstract

Abstract This paper presents a summary of the development of a semi-analytic reservoir model for gas reservoirs with various reservoir complexities. The types of reservoir complexities that have been considered in this study include; multiple reservoir layers in which the reservoir layers may be infinite or finite in extent, dual or single porosity systems, and wells that have been fractured. The reservoir model that has been developed and used in this study was constructed with the appropriate Laplace domain pressure and rate-transient solutions that are available in well testing literature. This reservoir model was developed to provide a more detailed and accurate means of analyzing or predicting the performance of a gas reservoir than is possible with a simple "type Curve" approach, yet would be more computationally efficient than a finite difference reservoir model. The results of the semi-analytic reservoir model have been validated with the reference solutions generated with a commercial finite difference reservoir simulator. The results of the semi-analytic reservoir model are comparable to the results of the finite difference simulator, yet require substantially less computation time and computer memory.