Recent progresses of microemulsions-based nanofluids as a potential tool for enhanced oil recovery

The worldwide demand of energy sources is increasing day by day. The trend of growing interest on renewable products is also increasing widely. Regardless of the advances of sustainable power sources, oil and gas industry stays as the world's essential fuel source. Therefore, deep concern is required for the improvement of oil recovery techniques as large amount of oil deposits still remains undiscovered even after the conventional recovery methods. Henceforth, chemical EOR (enhanced oil recovery) strategy is strongly suggested as a productive oil recuperation method by the infusion of synthetic substances to support oil recovery. Particularly oil recovery method by microemulsions (MEs) which assists with recuperating bypassed oil and remaining oil caught in the reservoir because of its capacity to plunge interfacial tension among oil and water to a degree and furthermore it modifies the wettability of supply rocks. In this review, an up-to-date synopsis on the synergistic impact of surfactant and NPs (nanoparticles) in MEs, type of surfactants and MEs, optimization in formulation of MEs, and applications of MEs in EOR have been discussed. A detailed description of selection and characterization of NPs for preparation of microemulsions-based nanofluids (MENF) in EOR application is furnished. Different influencing factors like interfacial tension, wettability alteration, adsorption, emulsion formation and fluid flow control are elaborately explained to show their effects on EOR by MENF. Advantages of MENF in EOR over other chemical methods are depicted. Finally, challenges and future prospects of MENF in EOR are deliberated to increase the oil recovery for mitigation of energy crisis.