Effect of nanoparticles on the performance of polymer/surfactant flooding for enhanced oil recovery: A review

It is well known that approximately 30% of Original Oil in Place (OOIP) is produced by water flooding. Therefore, to improve the residual oil recovery, the Enhanced Oil Recovery (EOR) methods are applied. Chemical flooding, as a promising EOR technique, has encountered some challenges in achieving its objectives, including the high cost of chemicals and its poor performance under oil and gas reservoir harsh conditions. Chemical nanofluids, as engineered colloidal suspensions of nanoparticles (NPs) in chemical-based fluids, have been recently discovered to address these challenges. This study comprehensively reviews the positive effects of NPs on the performance of polymer and surfactant flooding found in the literature. In addition, the enhancement of oil recovery through the use of disparate polymers and surfactants in combination with different NPs is investigated to bring the most potential NPs to researchers’ attention for future studies. It was concluded that NPs have great potential to improve rheological properties of polymers, and interfacial tension (IFT) between displacing and displaced fluid is reduced more than polymer and surfactant alone by adding NPs to the chemical solutions. Moreover, in the presence of NPs, the wettability of reservoir rock is altered towards more water-wet medium. NPs are also reported to have the ability to decrease the surfactant adsorption on porous media to some extent. Furthermore, the remaining challenges and possible future trends in this regard are reflected in the present paper. The collective review of the results presented in this study helps researchers to have a better understanding of NPs’ effects on Chemical Enhanced Oil Recovery (CEOR).