Polymeric Surfactant for EOR: Polymeric Sodium Methyl Ester Sulfonate (PMES) Performance in High Brine Salinity

The recent successes in the field have confirmed that chemical EOR is a viable technique for oil recovery. Numerous new chemicals and processes have been developed to increase the effectiveness and the economics of chemical EOR towards extreme reservoir conditions. Recently, an alternative chemical formulation using the new polymeric surfactant is developed to improve the conventional alkali/surfactant/polymer. This project evaluates the performance and compatibility of the new formulated Polymeric Sodium Methyl Ester Sulfonate (PMES) in high saline brine environment. The evaluations are made based on the ability of the PMES in viscosity control and in interfacial tension (IFT) reduction between oil and water. The project consist of series of experiments starting with fluid to fluid compatibility test, followed by interfacial tension and viscosity test of various combination of solutions, then lastly core flood tests for oil recovery simulation. Based on the results obtained from the constructive experimental tests, the optimum concentration of surfactant is 0.6% while the optimum concentration for alkali is 0.8%. At this optimum concentration, the interfacial tension of the fluid was significantly reduced while maintaining the desired solution viscosity even in high saline brine environment. By using the optimum surfactant and alkali surfactant concentrations, the tertiary recovery could reach 22.3% of the original oil in place when only 0.5 pore volume of the formulated slug and chase water was injected. In conclusion, it is certain that PMES has good tolerance level in high brine salinity without any momentous effects on its performance in interfacial reduction and viscosity control.