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Surface functionalization of silica nanoparticles to improve the performance of water flooding in oil wet reservoirs

Over the past few years, increasing attention has been devoted to the applications of special engineered nanoparticles in enhancing oil recovery. Earlier studies reported the effects of these particles on wettability alteration of reservoir rock. The present study presents a new method for modifying the surface properties of silica nanoparticles to make them more effective for enhancing oil recovery purposes. Contact angle, interfacial tension measurements, and core flood experiments were performed to examine the effects of these surface-modified nanoparticles on the interfacial interactions of injected water and reservoir rock and oil sample. To improve the performance of water flooding, surface-modified nanoparticles were produced in laboratory and it was found that amine-functionalized silica nanoparticles are significantly more effective than typical nanoparticles. Experimental results revealed that both contact angle and interfacial tension decrease more in the presence of functionalized nanoparticles. These results were confirmed by performing core flood tests which showed an 18% increase in total oil recovery compared to typical nanoparticles. Therefore, amine-functionalized silica nanoparticles could be more effective than typical nanoparticles in increasing the sweep efficiency by changing the wettability of reservoir rock and reducing oil/water interfacial tension. Moreover, it was observed that there is an optimum concentration for contact angle and interfacial tension reduced by nanoparticles and in concentration more than this threshold value the interfacial tension starts to increase slightly.