Primary Evaluation of a New Green Synthesized Anionic Surfactant, Micellar Behavior Analysis, and Flooding in Sandstone Reservoirs: Application in Chemical Enhanced Oil Recovery

Surfactants are among the most common chemical materials injected into reservoirs to improve oil recovery. They can optimize the significant roles of chemical enhanced oil recovery (EOR) including interfacial tension (IFT) and wettability alteration. However, surfactants are relatively expensive materials. In the last decade, researchers have been attempting to introduce environmentally friendly and affordable surfactant to meet chemical EOR goals; therefore, biosurfactants were developed. This research has tried to introduce and develop an anionic synthesized surfactant [powder extracted from cottonseeds (PECS)] and has characterized it on the basis of the EOR targets. For this purpose, by conducting the Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (HNMR) analysis, the existence of the saponin structure on this surfactant has been proved. Thereafter, to ensure the thermal stability, thermal gravimetric analysis (TGA) has been carried out. Moreover, studying the micellar behavior of PECS through electrical conductivity and surface tension analysis, it was perceived that the critical micelle concentration (CMC) is 1,200 ppm. Other solution properties including pH and density have also been measured. To investigate and ensure the validated potential for EOR parameters, IFT and wettability alteration analyses have been executed, proving the reduction of the IFT from 29.7 to 0.46 mN/m and the reduction of the contact angle value from 126.3 degrees to 57.8 degrees, respectively. Other surfactant properties in EOR application including emulsion stability and foamability have also been studied, representing 12-week emulsion stability and 12-minute foam half-life, respectively. In addition, gas flow rate effect for foamability of surfactant was measured. As an important parameter to investigate the performance of the novel introduced surfactant, the adsorption of surfactant on rock surface has been studied to determine the acceptable range for EOR application. Finally, coreflooding experiments showed a 7.6% increase of recovery factor.