Microemulsions stabilized with nanoparticles for EOR: A review

The global demand for energy sources is increasing every day. Despite advances in sustainable energy sources, the oil and gas industry remains the world's primary source of fuel. Even after conventional oil recovery methods, significant amounts of oil deposits still exist in reservoirs. Therefore, it is necessary to enhance Enhanced Oil Recovery (EOR) techniques. Among EOR methods, the use of microemulsions (MEs) has been extensively studied due to their high efficiency in extracting residual oil. Recently, the use of nanoparticles (NPs) has been proposed as stabilizers for microemulsions (MENPs). In this work, we present the concept, types, and mechanisms of EOR. Subsequently, we conducted a review of the characteristics and use of MEs and NPs in EOR. After this review, it was possible to conclude that the incorporation of nanoparticles into microemulsions is yielding better results than traditional microemulsion flooding for advanced oil recovery. The interactivity between NPs and reservoir fluids ensures alteration of wettability, reduction of interfacial tension, and reduction of oil viscosity. Nanoparticles have demonstrated their efficiency in stabilizing microemulsions for EOR. Inorganic nanoparticles, especially silica and metallic ones, are the most commonly used for advanced oil recovery and produce the most promising results. Finally, the challenges and future prospects of MENPs in EOR were also discussed. It is important to highlight that this study strongly contributes to the oil industry by presenting the latest sustainable and efficient alternatives to increase oil recovery and mitigate the energy crisis. •Silica and Iron nanoparticles are the most used for enhanced oil recovery.•The presences of NPs in MEs increase the oil recovery.•NPs make microemulsions more stable at high temperatures and pressure in addition to decreasing the IFT.