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چکیده
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Although water flooding is widely applied for enhanced oil recovery (EOR), its efficiency is often limited by excessive water production and scale formation, which damage reservoir permeability and reduce oil recovery. This study evaluates the performance of smart-water and hybrid smart-water-polymer injection as a novel approach to mitigate these limitations and enhance oil recovery. The objective is to optimize injection-water composition and assess its ability to control scale deposition, alter wettability, and enhance oil recovery by both experimental and simulation investigations. Compatibility tests between formation water and different injection waters were conducted to determine scale tendency, while contact-angle measurements were used to quantify wettability alteration. Based on these results, the optimal smart-water formulation was selected and combined with a polymer to form a hybrid injection fluid. Core-flooding experiments and simulations were then performed to derive water-oil relative permeability and capillary-pressure curves for various injection scenarios, including formation water, seawater, smart water, hybrid smart-water–polymer, and a combined smart-water plus hybrid smart-water–polymer strategy. Dynamic reservoir-simulation results show that smart-water injection increases oil recovery by 15.04% during secondary recovery, while hybrid smart-water–polymer flooding achieves a recovery of 23.32%. The smart water + hybrid-smart-water–polymer injection yields the highest total recovery improvement of 31.75% and shifts wettability from mixed-wet to predominantly water-wet conditions. These findings demonstrate that hybrid smart-water–polymer flooding provides a practical and superior alternative to conventional seawater injection.
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