Analisis Pengaruh Konsentrasi Surfaktan-polimer Terhadap Wettability Dan Recovery Factor Pada Batuan Karbonat Menggunakan Simulasi Reservoir

Currently, most of the oil is still trapped in the pore structure of the reservoir even after the primary recovery and secondary recovery schemes have been implemented. In Indonesian oil fields, there is an average of 60-70% of oil remaining in the reservoir after the primary and secondary stages. Therefore, it is necessary to carry out the Enhanced Oil Recovery (EOR) stage to increase oil production. The EOR method used in this study is chemical EOR, namely surfactant-polymer injection which is used to reduce interfacial tension (IFT) and increase the viscosity of the pressing fluid. In this research, chemical EOR was carried out to increase recovery factor and change wettability in carbonate fields using reservoir simulation. Reservoir elative was carried out using CMG-STARS with surfactant-polymer concentration as the parameter sensitivity. In this study, it was found that the injection of surfactant-polymer can change the wettability of carbonate rocks. Surfactant-polymer concentration is very influential on the recovery factor. In this study, the surfactant injection scenario produced an optimum recovery factor of 34.25% and in the polymer injection scenario the optimum recovery factor was obtained at 30.77%, while in the surfactant-polymer injection scenario the optimum recovery factor was obtained at 40.20 %. Based on the results of the injection scenario, it is known that the highest optimum recovery factor obtained is in the surfactant-polymer injection scenario, the result is an increase of 20.50% from the basecase (water injection) recovery factor of 19.70%