Experimental investigation of silica nanoparticle assisted Surfactant and polymer systems for enhanced oil recovery

Abstract

Enhanced oil recovery techniques are commonly used today in oil fields to boost oil production. The objective of the present study is to investigate the use of silica nanoparticles (NPs) with surfactants and polymers to increase the oil recovery from oil fields. Synergistic effects of surfactant, polymer, and nanoparticles on interfacial tension (IFT) reduction, wettability alteration, emulsification, and viscosity improvement are reported in this study. Core flooding experiments were performed in cores with different permeabilities to screen the reservoir on basis of rock properties. The dispersion of NPs in the aqueous solution of surfactant and polymer was characterized by stability analysis, Turbiscan analysis, dynamic light scattering (DLS), and zeta-potential measurements. The nanoparticles were able to further reduce the IFT between the surfactant solution and crude oil. The stability of nanofluids was increased when surfactant was added as evidenced by a higher zeta potential value (−39.6 mV). The addition of polymer led to even higher stability of the nanofluids as observed by the Turbiscan analyzer. A synergistic effect of NPs, surfactant, and polymer was observed in the core flooding experiments. The nanofluid system provided higher incremental oil recovery in high permeability core as compared to low permeability core. Different recovery mechanisms responsible for oil recovery by nanofluids like wettability alteration, disjoining pressure, log jamming, and pore channel plugging phenomena are discussed. The flooding results indicate that the injection of the designed slug increases the oil recovery up to 28% of the original oil in place after conventional water flooding. Therefore, the findings of this study can help for a better understanding of the use of silica NPs with surfactant and polymer as a chemical EOR agent. The result also helps in the screening of sandstone reservoirs where nanofluid could be employed.