Effect of SiO2 nanoparticles on the performance of L-Arg and L-Cys surfactants for enhanced oil recovery in carbonate porous media

Surfactant flooding as conventional chemical enhanced oil recovery (cEOR) was widely used to improve oil from the matured-producible reservoirs. Currently, nanoparticles (NPs) earned the vast attraction in EOR applications due to their sizes and physiochemical properties that possibly influence the viscosity, attraction, and IFT specifications of the fluid system. This work studied the effect of silica NPs on the performance of two synthesized amino-acid surfactants (lauroyl-arginine (L-Arg) and lauroyl-cysteine (L-Cys)) for improving oil recovery by considering the IFT reduction and wettability alteration. The conductivity, pH and turbidity measurements were considered to discover their critical micelle concentration (CMC). While, the visual observation and zeta potential were applied to analyze the dispersion stability of nanoparticles (NPs) within the surfactant solutions. The obtained results expressed that the high stability of SiO2 NPs achieved at 1000 ppm concentration when dispersed in surfactant solutions, and 2000 and 4500 ppm concentrations of L-Arg and L-Cys nano-surfactants are determined as CMC values, respectively. By adding SiO2 into surfactants, high reductions of 58% and 66% are obtained in the values of IFT and contact angle, respectively. Therefore, higher improvement in oil recovery was achieved by nano-surfactant flooding compared with the surfactant flooding, which are 13.1% and 11.9% OOIP, respectively.