Calculation of Gas Recovery Upon Ultimate Depletion of Aquifer Storage

Abstract

The recovery of cushion gas upon ultimate depletion of an aquifer storage reservoir is dependent upon reservoir heterogeneity, aquifer strength, production rate, and fluid and rock properties. This study illustrates the use of multi-dimensional, two-phase, compressible fluid flow calculations to simulate the depletion. Results that illustrate the non-exhaustive examination of the efJects of heterogeneity, aquifer strength, and gas production rate are presented. The study indicates a strong dependence of recovery upon reservoir heterogeneity. The multi-dimensional type of calculation employed appears necessary to reliably estimate recoverable cushion gas for any particular reservoir.