Wettability alteration of sandstone oil reservoirs by different ratios of graphene oxide/silica hybrid nanofluid for enhanced oil recovery

Abstract

Nowadays, there has been a recognition of the remarkable potential of nanofluids and microorganisms as eco-friendly agents for enhanced oil recovery. on the other hand, one of the unique strategies for boosting hydrocarbon recovery is altering the wettability of the rock surface of oil and gas reservoirs. Herein, a nanohybrid that combines graphene oxide (GO) and silica (SiO2) was synthesized using a low-temperature, facile, and eco-friendly approach (sol-gel). GO-SiO2 nanocomposite was characterized with the aid of XRD, SEM, and FTIR analyses. Afterward, Nanofluids with different concentrations (0.005, 0.01, 0.015, and 0.02 wt%) of GO-SiO2 nanocomposite at various ratios (1:1, 1:2, and 2:1) were prepared using a surfactant-free and pH-neutral approach with a salinity of 30,000 ppm. The results of the Zeta potential measurement reveal that the manufactured nanofluids have great stability and the ratio of 1:1 was the most effective ratio for improving the reservoir wettability change from oil-wet to water-wet. At a higher temperature of 80 °C compared to the ambient condition of 25 °C, a more significant change in wettability was observed (23° to 161°). At the optimal concentration of nanofluid (0.015 wt%), the contact angle increased from 23° (on a non-treated surface) to 161°. These findings suggest that GO-SiO2 has great potential as an affordable, flexible, and environmentally friendly natural nanofluid, particularly under harsh conditions for the EOR process.