Impact of trapping of residual oil by mobile water on recovery performance in miscible enhanced oil recovery processes

摘要

In this paper we examine how residual oil trapping by mobile water affects the recovery perforamnce of miscible EOR processes. The objectives of the study are (1) to develop a multiphase, numerical model to investigate factors affecting water-blocking and the release of oil from dendritic states; (2) to evaluate performance of miscible processes and forecast displacement efficiency and recovery under a variety of operating conditions, and (3) to determine the "optimum" water-volvent ratio to be used in a miscible Water-Alternate-Gas (WAG) process. Using the multiphase flow model, we considered the oleic phase as two parts, a mobile phase and a trapped phase, and studied the effects of capillary forces, solvent viscosity, fraction of trapped oil, dispersion and mass transfer coefficients on recovery performance. Guidelines for determining to optimum water-solvent ratio to be used in a miscible WAG process are discussed.