Experimental Investigation of the Microscopic Displacement Mechanisms of Surfactant Flooding in High Salinity and High Temperature Conditions

The high amount of trapped crude oil in carbonate reservoirs is the main objective of the various Enhanced Oil Recovery techniques. However, the harsh conditions of these reservoirs, such as high temperature, incompatibility of formation brine and sea water ions, as well as oil-wet conditions, are among the factors which face the desired approach with serious challenges. Therefore, in this study, the stability, interfacial tension, wettability alteration, and microvisual flooding experiments have been investigated using two types of anionic surfactants [DSS and SDBS] and two types of cationic surfactants [CTAB and CPC]. The amount of recovered oil was 63%, 48%, 44% and 35% respectively. The highest recovery factor was due to implementation of the DSS surfactant. Also, in order to investigate the effect of surfactant on the wettability alteration, the reservoir rock samples were aged for two weeks. Contact angle measurement of 160 degree has proved the oil wetness condition. Wettability alteration has been investigated using treating solutions of anionic surfactants DSS, SDB and cationic surfactants [CTAB and CPC]. Obtaining results demonstrate contact angles of 100, 90, 60 and 48.7 respectively. Finally, the highest wettability change is due to the application of CPC which alters the contact angle from 160 degrees to 48.7.