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چکیده
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A significant portion of the world oil remains trapped in mature reservoirs, locked in place by unfavorable fluid-rock interactions and capillary forces. In this regard, the efficiency of enhanced oil recovery (EOR) hinges on the fundamental modification of fluid-rock interactions, specifically wettability and interfacial tension. While low-salinity water, polymers, and nanoparticles individually show potential for IFT reduction and wettability alteration, their synergistic combination within a tailored formulation for complex porous media is poorly understood. This research bridges this critical knowledge gap by engineering and evaluating a novel class of synergistic nanofluid, combining activated carbon, gamma alumina (γ-Al2O3) nanoparticles, and polymer. In this study, the new NF is known as ANP. Through rigorous physicochemical characterization and scale coreflooding experiments, we demonstrate that the optimized NF (notably at 550 ppm) fundamentally modifies fluid-rock interactions. The primary mechanism, attributed to the expansion of the electrical double layer by LSW, is effectively potentiated by the nanoparticles and polymer. The mechanism leading to a dramatic wettability alteration from strongly oil-wet (148°) to water-wet (37°) and a substantial reduction in IFT from 27.23 to 3.4 mN/m. This multi-scale performance translates directly to peak oil recovery in displacement tests. This research provides a foundational and scalable strategy for employing nanofluid-based polymers as next-generation injection fluids, not only as a highly effective enhanced oil recovery agent but also as a strategic tool for minimizing formation damage, thereby offering a new paradigm for efficient field implementation.
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