Enhanced oil recovery using a novel non-ionic surfactant synthesized from olive oil: Performance and synergistic effects

In recent years, there has been increasing focus on the application of natural surfactants in enhanced oil recovery (EOR) due to the environmental concerns associated with conventional surfactants. This study presents a systematic approach in this field by introducing a novel non-ionic surfactant synthesized from olive oil through a two-step synthesis process. The synthesis of olive oil alkanolamide (OOAA) surfactant was confirmed using FTIR and characterized by GC-MS analysis. The synthesized OOAA surfactant showcased favorable attributes including effective emulsification, wettability modification, interfacial tension reduction, limited adsorption losses, and efficient oil displacement. Critical micelle concentration (CMC) of OOAA surfactant was found to be very low, 50 ppm at 303 K. At CMC, the interfacial tension (IFT) of synthesized OOAA surfactant was found to be 18.75 mN/m, which further decreased by 26 % at the optimal salinity of the NaCl solution. The contact angle study revealed significant wettability alteration for the optimized salt concentration. Adsorption of the surfactant onto rock surfaces was analyzed by using two adsorption isotherms. The Langmuir adsorption isotherm emerged as the best fitting model, yielding an R2 value of 0.899. The formulation of OOAA surfactant/PHPA/NaCl solution showed shear thinning behavior and also exhibited viscoelastic properties. The synergism of OOAA surfactant with PHPA polymer led to a substantial tertiary recovery of 31 % OOIP over the conventional water flooding. These comprehensive findings underline the potential of the synthesized OOAA surfactant for enhancing oil recovery in sandstone reservoirs.