A synergistic nano-brine formulation for enhanced oil recovery through interfacial engineering in carbonate reservoirs.

This study presents a novel approach for enhanced oil recovery (EOR) in carbonate reservoirs through the synergistic use of engineered low-salinity brine and nanoparticles. Generally, conventional studies of nanofluid-EOR in carbonates largely focus on the macroscopic effects of metal oxides, leaving the design and behavior of custom multi-component nanofluids engineered to control multiple interfacial forces simultaneously poorly understood. In this study, the nanoparticle was synthesized by functionalization with other chemicals (potassium laurate and Triton X-100). The results showed that excellent colloidal stability, evidenced by a zeta potential of -58.46 mV at 80 ppm and pH 4.5. Also, contact angle analysis demonstrated a wettability shift from oil-wet to strongly water-wet. Core flooding tests achieved a significant incremental oil recovery of 31.11%, driven by the synergistic reduction of interfacial tension, effective wettability alteration, and enhanced structural disjoining pressure. The results identify the optimal and cost-effective nanofluid concentrations (80 ppm) for field-scale injection into carbonate reservoirs. These findings underscore the promise of engineered nanofluid brine systems as a viable and sustainable EOR strategy, providing valuable direction for the development of advanced materials in energy and industrial applications.