Performance Evaluation of Silica–Graphene Quantum Dots for Enhanced Oil Recovery from Carbonate Reservoirs

Abstract

Nanomaterials have shown significant performances in enhancing oil recovery by reducing the interfacial tension (IFT) and contact angle (CA) of the rock/crude oil/water system in porous media. This is evaluated by the synergistic impact of silica–graphene quantum dots (Si–GQDs) on IFT reduction and wettability alteration for the purpose of enhancing oil recovery from carbonate reservoirs. The silica–graphene quantum dots (Si–GQDs) were synthesized by combining graphene oxide and silicon oxide nanoparticles (NPs) and characterized using several analytical techniques. Both distilled water and brine, as dispersion media, were used to prepare nanofluids by dispersing the synthesized Si–GQDs at different concentrations from 1000 to 10,000 ppm. The main properties of the nanofluids including pH, density, and conductivity were measured to evaluate their quality and the performance of Si–GQDs. In addition, the prepared nanofluids were used in the measurements of IFT and contact angles at different concentrations of the synthesized Si–GQDs in both types of used water. The obtained results show that the DWN1000 nanofluid formulated from dispersing 1000 ppm Si–GQDs in distilled water enables an additional 14.4% OOIP oil recovery due to a significant reduction in the value of IFT from 28.3 to 9.5 mN m–1, improving rheology behavior and wettability alteration toward a strong water-wet system from 134 to 61° contact angles.