Crude oil has been one of the most important natural resources since 1856, which was the first time a world refinery was constructed. However, the problem associated with trapped oil in the reservoir is a global concern. Consequently, Enhanced Oil Recovery (EOR) is a modern technique used to improve oil productivity that is being intensively studied. Nanoparticles (NPs) exhibited exceptional outcomes when applied in various sectors including oil and gas industries. The harshness of the reservoir situations disturbs the effective transformations of the NPs in which the particles tend to agglomerate and consequently leads to the discrimination of the NPs and their being trapped in the rock pores of the reservoir. Hence, Electromagnetic-Assisted nanofluids are very consequential in supporting the effective performance of the nanoflooding process. Several studies have shown considerable incremental oil recovery factors by employing magnetic and dielectric NPs assisted by electromagnetic radiation. This is attributed to the fact that the injected nanofluids absorb energy disaffected from the EM source, which changes the fluid mobility by creating disruptions within the fluid’s interface and allowing trapped oil to be released. This paper attempts to review the experimental work conducted via electromagnetic activation of magnetic and dielectric nanofluids for EOR and to analyze the effect of EM-assisted nanofluids on parameters such as sweeping efficiency, Interfacial tension, and wettability alteration. The current study is very significant in providing a comprehensive analysis and review of the role played by EM-assisted nanofluids to improve laboratory experiments as one of the substantial prerequisites in optimizing the process of the field application for EOR in the future.

The utilization of metal-oxide nanoparticles in enhanced oil recovery (EOR) has generated considerable research interest to increase the oil recovery. Among these nanoparticles, alumina nanoparticles (Al₂O₃-NPs) have proved promising in improving the oil recovery mechanism due to their prominent thermal properties. However, more significantly, these nanoparticles, coupled with electromagnetic (EM) waves, can be polarized to reduce water/oil mobility ratio and create disturbances at the oil/nanofluid interface, so that oil can be released from the reservoir rock surfaces and travelled easily to the production well. Moreover, alumina exists in various transition phases (γ, δ, θ, κ, β, η, χ), providing not only different sizes and morphologies but phase-dependent dielectric behavior at the applied EM frequencies. In this research, the oil recovery mechanism under EM fields of varying frequencies was investigated, which involved parameters such as mobility ratio, interfacial tension (IFT) and wettability. The displacement tests were conducted in water-wet sandpacks at 95 °C, by employing crude oil from Tapis. Alumina nanofluids (Al₂O₃-NFs) of four different phases (α, κ, θ and γ) and particle sizes (25–94.3 nm) were prepared by dispersing 0.01 wt. % NPs in brine (3 wt. % NaCl) together with SDBS as a dispersant. Three sequential injection scenarios were performed in each flooding scheme: (i) preflushes brine as a secondary flooding, (ii) conventional nano/EM-assisted nanofluid flooding, and (iii) postflushes brine to flush NPs. Compared to conventional nanofluid flooding (3.03–11.46% original oil in place/OOIP) as incremental oil recovery, EM-assisted nanofluid flooding provided an increase in oil recovery by approximately 4.12–12.90% of OOIP for different phases of alumina. It was established from these results that the recovery from EM-assisted nanofluid flooding is itself dependent on frequency, which is associated with good dielectric behavior of NPs to formulate the oil recovery mechanism including (i) mobility ratio improvement due to an electrorheological (ER) effect, (ii) interfacial disturbances by the oil droplet deformation, and (iii) wettability alteration by increased surface-free energy.