Novel smart water-based titania nanofluid for enhanced oil recovery

Abstract

Smart water application in carbonate reservoirs has been recently gained a lot of attention by researchers as a low-cost enhanced oil recovery (EOR) method. In this study, for the first time, the behavior of different smart waters in the absence and presence of TiO2 nanoparticles (NPs) has been investigated by analyzing their effect on wettability alteration, interfacial tension (IFT) reduction, and oil recovery improvement during the spontaneous imbibition process. The zeta potential analysis of TiO2 NPs in seawater (SW) shows a detrimental and insufficient effects of divalent cations (Ca2+ and Mg2+) and monovalent cations (Na+ and K+) on the nanofluid (NF) stability at a pH value higher than its point of zero charge (PZC), respectively, while the detrimental effect of divalent anions (SO42−) is observed at pH values lower than PZC. The results of contact angle measurements show a little improvement in the wettability alteration changing from modified SWs (MSWs) to diluted MSWs (dMSWs) and a significant improvement changing from dMSWs to dMSWs-based NF that is observed a diverse behavior for the IFT reduction, emphasizing the significant role of NPs addition to smart waters and decreasing the salinity of smart waters. During the imbibition experiments, the performance of all types of smart waters is drastically increased in the presence of TiO2 NPs confirming the results of contact angle experiments, occurred by their retention on the rock surface and movement through the porous media depending on the type of ions presented in the smart waters.