Application of a new anionic surfactant based on sesame oil by Alkali-Surfactant (AS) injection in chemical enhanced oil Recovery: Characterization, mechanisms and performance

Abstract

This study is centered on creating an anionic surfactant using edible sesame oil for enhanced oil recovery (EOR) objects. The surfactant was synthesized under esterification and sulfonation processes. Characterization analyses were performed to describe the surfactant and evaluate its temperature stability. Related experiments were conducted to investigate phase behavior, surface activity, and EOR implications of the surfactant. A chemical flooding experiment was carried out. This involved injecting the surfactant along with the appropriate levels of salinity and alkalinity, into a carbonate plug. Additionally, the ability of the surfactant to generate and maintain foam and emulsion was examined. The surface tension values were reduced from 64 to 33.07 mN/m, and the interfacial tension (IFT) values dropped from 21 to 0.81 mN/m. Through these experiments, the critical micelle concentration (CMC) of the surfactant was determined to be 800 ppm. Upon reaching the CMC, the IFT further decreased to 0.38 and 0.14 mN/m at optimal salinity and alkalinity levels respectively. The previously hydrophobic carbonate surface underwent significant improvement in wettability, transitioning to hydrophilic behavior. This shift was evident as the contact angle decreased from 130.2° to 58.8° within a brief 60-minute equilibration period, representing a suitable wettability state for EOR. The surfactant exhibited an emulsion and foam stability period lasting 35 days. Additionally, its ability to function effectively in the presence of sodium chloride (NaCl) ions was verified with compatibility demonstrated at salinity levels below 100000 ppm. Ultimately, the flooding outcomes displayed a notable 16.18 % enhancement in oil recovery when employing the optimum fluid.