Enhanced Oil Recovery Using Nanofluid Injection in Marginal Wells: A Techno‐Economic Evaluation for Prolonged Field Life and Job Retention in Oil‐Dependent Regions

ABSTRACT Marginal oil wells, often abandoned due to low pressure and declining productivity, still contain significant untapped reserves that could support energy security and local economies. This study investigates nanofluid‐enhanced oil recovery (EOR) as a cost‐effective and scalable solution for revitalizing such wells. Silica‐ and cobalt ferrite (CoFe 2 O 4 )‐based nanofluids, stabilized with sodium dodecyl sulfate (SDS), were synthesized and tested on sandstone and carbonate cores under simulated reservoir conditions. Core flooding experiments demonstrated an incremental oil recovery of 14%–18% at an optimal concentration of 0.05 wt%, driven by interfacial tension reduction (32 to 6 mN/m) and wettability alteration (115°–45°). Economic analysis showed a recovery cost of $5.30/barrel and a breakeven oil price of $34, with a return on investment up to 2.4×. A Techno‐Socio‐Economic Viability Index (TSEVI) indicated strong socio‐economic benefits, including 60%–75% employment retention and positive net present value. Overall, nanofluid EOR presents a technically efficient, economically viable, and socially beneficial approach for extending the productive life of marginal oilfields.