Enhanced oil recovery via metal oxide nanoparticles: A review of recent advancements, core mechanisms, and future outlook

Global conventional oil production has declined, and large volumes of hydrocarbons remain unrecovered in active reservoirs. This has increased demand for advanced enhanced oil recovery (EOR) technologies. Conventional methods, including chemical, thermal, and gas injection, to improve recovery but are often constrained by high costs, limited efficiency, and environmental and geological challenges. Nanotechnology is an emerging sector with high potential for applications across many sectors, including EOR. Metal oxide nanoparticles (NPs), such as alumina (Al₂O₃), titania (TiO₂), silica (SiO₂), zinc oxide (ZnO), and iron oxide (Fe₂O₃), have gained considerable attention throughout the years. Owing to their tunable surface properties, stability, and physicochemical versatility, screening criteria, these nanomaterials offer multiple pathways for improving oil recovery. The core mechanisms include changes in wettability, reductions in interfacial tension and disjoining pressure, foam stabilization, and variations in viscosity within porous media. This review aims to provide a comprehensive overview of the role of metal oxide nanoparticles in EOR, with emphasis on their synthesis, physicochemical characteristics, stability, effectiveness of nanoparticles, and practical applications under reservoir conditions. This review also focuses on the field challenges, such as pore jamming, retention losses, techno-economic models, and environmental profiling. By bringing together insights from experimental studies, theoretical applications, and field trials, this paper aims to become a bridge between laboratory research and large-scale industrial applications. The main goal is to create a tiered deployment roadmap (micro-pilots to full-field by 2028–2030), decisively advancing nano-EOR from lab promise to industrial reality. • Metal oxide nanoparticles boost oil recovery by altering wettability, reducing IFT, and modifying viscosity. • Silica is cost-effective for sandstone, alumina favors carbonate reservoirs, and iron oxides offer magnetic controllability. • High costs, scalability challenges, and reservoir instability hinder widespread field application. • Sustainable "green" synthesis methods are essential to mitigate risks like aquatic toxicity and soil contamination. • Smart trigger-responsive systems and machine learning will drive future EOR optimization.