A Review on the Investigation of Acetylated Starch & Silica Nanoparticles for Enhanced Oil Recovery (EOR) Application

The decline in conventional oil recovery efficiency necessitates the development of advanced tertiary methods such as Enhanced Oil Recovery (EOR). This study investigates a hybrid nanofluid composed of acetylated cassava starch and silica nanoparticles for application in chemical EOR. Acetylated starch was synthesized to enhance viscosity and thermal stability, while silica nanoparticles were incorporated for their interfacial activity and wettability alteration capabilities. Comprehensive laboratory experiments were conducted to evaluate the hybrid fluid’s physicochemical, rheological, and recovery performance. Characterization using FTIR, XRD, SEM, and TGA confirmed successful functionalization and improved thermal resilience. Rheological tests demonstrated shear-thinning behavior with high viscosity retention. The hybrid fluid also achieved a 57.7% reduction in interfacial tension and altered sandstone wettability from oil-wet to strongly water-wet conditions. Core flooding tests revealed a recovery factor of 68.9%, outperforming starch-only, silica-only, and brine controls. The synergy between the polymer and nanoparticles enhanced colloidal stability, flow performance, and oil displacement efficiency under simulated reservoir conditions. The use of cassava starch as a biodegradable and locally sourced material underscores the environmental and economic viability of the formulation. These findings support the potential of acetylated starch–silica nanofluids as sustainable, high-performance EOR agents.