Synthesis and Physicochemical Evaluation of an Olive Oil-Derived Anionic Surfactant: Effects on Interfacial Tension, Wettability Alteration, and Oil Recovery Efficiency

The economic and environmental challenges associated with commercially available surfactants have driven the development of sustainable alternatives for enhanced oil recovery (EOR). The study explores the synthesis and application of an olive oil-derived anionic surfactant for EOR. The synthesized surfactant exhibits superior surface and thermodynamic properties, favoring interfacial adsorption over bulk micelle formation. Evaluation of the key EOR properties, including emulsification, rock wettability, and interfacial tension, showed that the surfactant achieved a low IFT (0.21 mN/m) against crude oil at its critical micelle concentration (CMC), with further reduction to 96.4% at optimal salinity (0.0075 mN/m), demonstrating its potential for use in saline reservoirs. Thermal stability tests revealed minimal degradation up to 150 °C, suggesting its suitability for use in high-temperature reservoirs. Additionally, it effectively alters the wettability of oil-wet sandstone cores, as evidenced by a substantial decrease in the contact angle. When combined with polymer injection, the process achieved a notable 18.56% increase in oil recovery, underscoring the efficacy of polymer-augmented surfactant flooding in mobilizing residual oil. Furthermore, biodegradability testing confirmed the eco-friendly nature of the surfactant.