Nanoparticles in enhanced oil recovery: state-of-the-art review

Abstract Against the backdrop of escalating global energy demand projected to rise by 50% within the next decade, this comprehensive review aims to evaluate and analyze the transformative potential of nanomaterials in Enhanced Oil Recovery (EOR) techniques. The study specifically examines the synergistic interactions between various nanoparticles (NPs) and chemical modifiers, while addressing the critical challenges in practical implementation. The scope encompasses a systematic assessment of different NPs types, their mechanisms of action, their optimization for field-scale applications, and the identification of research gaps that need to be addressed for industrial-scale deployment. The review methodology employs a multi-faceted analytical approach, combining systematic analysis of experimental studies with a critical evaluation of field implementation challenges. The performance of metal oxides and silica NPs was critically reviewed by examining their interactions with polymers, surfactants, and low salinity brines (LowSal) across diverse reservoir conditions. The analysis particularly focused on correlating NPs characteristics (type, concentration, size, and surface area) with their impact on chemical modifier adsorption, recovery factors, wettability alterations, and interfacial tension (IFT) modifications. Our analysis revealed that silica (SiO 2 ) and alumina (Al 2 O 3 ) NPs demonstrate superior performance in EOR applications, with distinct advantages under specific reservoir conditions. SiO 2 NPs achieve 30–50% IFT reduction under optimal conditions, particularly at lower temperatures, while exhibiting excellent compatibility with existing EOR infrastructure. Al 2 O 3 NPs exhibit remarkable stability across various temperature ranges, while zirconium oxide (ZrO₂) NPs show up to 40% IFT reduction at elevated temperatures, offering versatility for different reservoir types. Optimal NP concentration was identified between 0.1–0.5 wt%, with higher concentrations potentially causing adverse effects such as pore blockage and particle aggregation. The combination of NPs with surfactants or polymers demonstrated synergistic effects, with SiO 2 NPs–surfactant combinations achieving an additional 10–20% IFT reduction compared to SiO 2 NPs alone. Surface modifications and optimized salinity conditions improved NPs stability by 20–30% in high-salinity environments, addressing a key challenge in field applications. Importantly, recent field trials underscore these laboratory findings by demonstrating a near 98% increase in cumulative oil production (from 15,502 to 30,682 bbl) in a Colombian heavy-oil reservoir following Ni–Pd–doped Al 2 O 3 nanofluid injection. These operations also improved API gravity (from 11.6° to 13.4°) and significantly reduced viscosity (from 39,987 cP to 11,734 cP), economically, the steam requirements and associated costs reduced with nanofluid treatments in only one field trial up to 48% cost reduction attributed to lower steam usage and enhanced production. Highlighting the practical impact and longevity of NPs-based EOR technologies in real-field settings. This review thus provides a systematic framework for selecting and optimizing NPs-based EOR systems while identifying critical research needs in scaling up laboratory successes to commercial deployment. The findings emphasize the need for long-term stability studies, cost-effective synthesis methods, and environmental impact assessments to fully harness the potential of nanotechnology in the petroleum industry.