Document Type : Article
National Iranian South Oil Company (NISOC), Ahwaz, Iran
Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
IOR Research Institute, Negar Alley, Valiasr Street, Tehran, Iran
In this work, hybrid of silica nanoparticles (NPs) with sulfonated copolymer has been prepared in order to improve the copolymer properties for enhanced oil recovery (EOR). Some tests are done to find the effectiveness of injecting fluid on recovery factor (RF), such as; contact angle (CA), interfacial tension (IFT), inherent viscosity and eventually Micro-Model (MM) flooding. In CA test, wettability alteration from oil-wet (OW) to water-wet (WW) is reached by sedimentation and adsorption of NPs on the rock slice. In addition, IFT reduction is obtained by increasing the NaCl concentration. The viscosity change is investigated for the hybrid and copolymer under simulated high-temperature oil reservoir conditions. It is found that silica NPs-copolymer hybrid exhibits better inherent viscosity and thermal stability than copolymer alone. At MM flooding, more RF and produced oil in water (O/W) emulsion is obtained from hybrid respect to polymer alone. Hybrid injection results in IFT reduction, increment in viscosity and O/W emulsion formation that cause enhancement in capillary number (Nca) and RF and subsequently reduction in residual oil saturation. Therefore, NPs-copolymer hybrid could be a much better candidate than even high-performance polymer solutions for EOR process.