Numerical study for continuous surfactant flooding considering adsorption in heterogeneous reservoir

Abstract

Surfactant flooding is a proven Enhanced Oil Recovery (EOR) technique used for mobilizing residual oil trapped in the reservoir. The mechanism of surfactant injection into reservoirs for improving oil recovery factor is to alter the fluid/fluid interaction by reducing interfacial tension between oil and brine. Besides, they alter fluid/rock properties via wettability alteration of the porous medium. Surfactant flooding has been applied on several field pilot projects. This research mainly focuses on investigating the continuous surfactant flooding for Bentiu oil reservoir in Sudan. The main method used in this study is numerical analysis of compositional flow using STARS software provided by the Computer Modelling Group Company (CMG-STARS). The research also proposed new surfactant for the continuous flooding. Moreover, the surfactant ability to increase the recovery factor was studied and compared to the traditional water flooding recovery method. Furthermore, for accuracy purposes, the risk of surfactant adsorption in the typical heterogeneous field was studied. The surfactant adsorption was calculated from static batch adsorption test by the surface tension method. The simulation results showed that the newly proposed surfactant improved total oil recovery by ∼70%. The surfactant flooding showed lower water cut when compared to conventional water flooding. The improvement in the oil recovery and water cut was a good indication for the suitability of surfactant flood in the heterogeneous reservoir.