Applying membrane technology for preparing low salinity for hybrid nanofluid, surfactant, and alkaline enhanced oil recovery process

The use of an individual or hybrid enhanced oil recovery (EOR) technologies and their main active mechanisms are complicated issues that should be investigated in more detail. Recently, nanofluids and smart water have gained special attention as appropriate enhanced oil recovery (EOR) technologies due to their excellent capability in changing interfacial properties. In addition, surfactant, alkaline and their combination are conventional chemical EOR agents. This study was aimed at evaluating synergistic/antagonistic of hybrid smart-nanofluid-alkaline solutions with examination of different combinations of these agents based on seawater and treatment of seawater by membrane desalination process. Firstly, the salinity of seawater decreased from 39650 ppm (ionic strength of about 0.7 M) to 4275 ppm (ionic strength = 0.09 M) using microfiltration membrane. Secondly, a hydrophilic nanoparticle of SiO₂ was synthesized from rice husk with the mean particle size of 70 nm. In the third stage, the effects of salinity, alkaline, SDS as anionic surfactant, SiO₂ and PVP as stabilizer of SiO₂ were investigated through interfacial tension (IFT), critical micelle concentration (CMC), microemulsion, and contact angle measurements as well as spreading coefficient calculation. Even though dilution of seawater showed an appropriate modification in the spreading coefficient due to the favorite wettability alteration, the addition of SiO₂ nanoparticles showed an insignificant modification. It was also revealed that the individual SDS had better performance compared to all considered hybrid solutions because of experiencing the most IFT reduction (∼0.1 mN/m), favorite wettability alteration for fracture carbonate reservoir (155° to 35°), the highest spreading coefficient (∼-0.03) and the lowest CMC value (∼200 ppm), as well as fast oil/water separation.