Abstract
The application of nanoparticles (NPs) to improve oil recovery is gaining wide acceptance in the petroleum industry in recent times. Due to their size and set chemical characteristics, NPs can be used to enhance oil recovery in carbonate reservoirs by altering the rock wettability and reducing oil–brine interfacial tension (IFT). Also, when used with surface-active agents like surfactant (cationic, anionic or non–ionic) in low–salinity waterflooding (LSWF), NPs can enhance the performance of surfactant. This study focuses on the implications of combining green NPs with surfactant and low–salinity water for EOR applications in carbonate reservoirs. A NP was synthesized from a green source, rice husk, and then characterized using XRD, FTIR, TGA and SEM analyses. A cationic surfactant, Aspiro S 6420, was added in the nanoemulsion of silica nanoparticle (SNP) and 1% diluted seawater (dSW). The SNP-Surfactant-1%dSW nanoemulsion was investigated for its beneficial effects for EOR applications. Zeta potential measurements were carried out for various brine dilutions, then for 1% dSW and surfactant, and finally 1%dSW–Surfactant–SNP nanoemulsions. The measurements showed that the zeta potentials are highly positive, confirming the stability of the nanoemulsions and alteration of rock wettability. Interfacial tension (IFT) between oil and brine were measured at a temperature of 86°C. The addition of surfactant (Aspiro S 6420) led to significant drop in IFT between oil and brine. Finally, when SNPs were added to the 1%dSW–Surfactant emulsions, the IFT reduced significantly, confirming that the combination of low salinity brine–cationic surfactant (Aspiro S 6420)–SNP can be used as a promising injection fluid to recover oil from carbonate reservoirs.
