Critical investigation of zwitterionic surfactant for enhanced oil recovery from both sandstone and carbonate reservoirs: Adsorption, wettability alteration and imbibition studies

Abstract

Abstract Surfactant flooding, a proven method of oil recovery from conventional reservoirs, is limited due to its adsorption on reservoir rocks. Surfactant adsorption leads to modification of wetting state of reservoirs, but it is dependent on the type of surfactant. In present study, a zwitterionic surfactant was selected to study its wettability alteration and adsorption behavior on sandstone and carbonate samples. The adsorption profile was fitted to isotherm models and best-fitted model was determined by R2 values. Zeta potential suggested hydrophilic interaction between the surface and surfactant. Increase in salinity and alkalinity had opposite effects on surfactant adsorption. Surfactant was found effective in altering the wetting state of rock surface. Increase in salinity and alkalinity was found to improve the wettability alteration effectiveness. Effective wettability alteration was also tested by spontaneous imbibition into core samples. Thus, zwitterionic surfactant was found suitable for application in both sandstone and carbonate reservoirs.