Implications of anionic and natural surfactants to measure wettability alteration in EOR processes

Minerals surface properties have played a substantial to predict the rock mineralogy and chemical materials interactions, especially in chemical flooding (e.g., polymers, surfactant). In this paper, two different surfactants; nonionic surfactant (Zizyphus Spina Christi) and anionic surfactant (henceforth; SDBS) were used to experimentally investigate the minerals of reservoir rocks especially carbonate reservoirs and measure wettability changes accordingly. The contact angle evaluations have depicted that utilized surfactants change the wettability of pellet surfaces of calcite, dolomite, quartz, and anhydrite to neutral-wet or slightly water-wet. As it was observed, SDBS provided the maximum wettability changes for quartz surface. Moreover, the Zizyphus Spina Christi and SDBS have provided efficient performances on the decrease of wettability changes and residual oil saturation in dolomite core and quartz core, respectively. According to the results of this study, the oil recovery factor with anionic SDBS surfactant for calcite, dolomite, and quartz plugs are 66%, 41%, and 93%, respectively. This increase is more visualized for quartz cores that indicated the compatibility of this surfactant with quartz core samples.