Abstract
Surfactants are favorable chemical additives that are widely utilized in enhanced oil recovery (EOR) due to their inherent abilities such as wettability alteration and interfacial tension (IFT) reduction. However, most of the commercially available surfactants are expensive, hazardous to the environment, and can readily adsorb on the surface of the porous rocks. The present work investigates the possible application of a novel plant-based natural surfactant derived from the weed, Eichhornia crassip es, for EOR The wettability alteration and IFT measurements have been performed in reservoir-like conditions (i.e., high temperature and pressure). Adsorption of the surfactant at the oil-water interface has been studied. In addition, the effect of the natural surfactant on the rheological behavior of xanthan gum has been analyzed over a wide range of shear rates, frequencies, and temperatures. Further, core flooding experiments have been carried out by injecting the surfactant-polymer slugs of different concentrations into the sandstone core sample under reservoir-like conditions. Effective reduction values of similar to 37-41% in IFT and similar to 43% in wettability were observed with increasing surfactant concentration. Moreover, enhancement in the rheological properties and 13.3-22.4% additional oil recovery demonstrate the possible applications of this natural surfactant-polymer system in EOR.