Effect of Different Surfactants and Nanoparticles on Pore-Scale Oil Recovery Process Using Heterogeneous Micromodel

The application of surface-active agents during oil recovery process is ubiquitous. It is essential to achieve a satisfying oil recovery rate with low dosage of surface-active substances in an environment-friendly manner. Despite the wide application of surface-active agents, the impact of individual and the combination of surface-active agents on the microscale multiphase flow and interfacial phenomenon have not been systematically investigated. In this work, idealized pore-throat network micromodels were employed as the surrogate of the porous media to study the influence of surface-active agents on the oil recovery involving nonionic, anionic, zwitterionic surfactants, and nanoparticles. Oil recovery efficiency and residual oil characteristic in different permeable regions were quantitatively analyzed. Anionic surfactants resulted in the highest oil recovery of 79% and were selected to formulate composite agents. The combination of anionic and zwitterionic surfactants resulted in better overall oil recovery which was up to 84%, yet complicated interfacial phenomenon was observed. To comprehend the complex interactions between crude oil and assorted surface-active agents, the impact of interfacial tension, wettability, and emulsification on oil-brine flow behaviors and final oil recovery was discussed providing an insight on the efficient and cost-effective application of surface-active agents on enhancing oil recovery.