Formula Optimization And Performance Evaluation Of Low Interfacial Tension Oil Displacement System

ASP formula that is the solution of alkaline,surfactant and polymerhas higher ability of enhancing oil recovery because of the synergistic effect between them and so can greatly increase the oil recovery in mature oil fields.The formula of ASP was optimized for a Chinese mature oil field that with acidic heavy oil and the performancewas evaluated systematically.The experimental results showed that polymer D2 had the highest molecular weight,the best effect of viscosity increase,and matching with pore throat of the formation,therefore preferred polymer D2 as the thickener.Surfactant JS-33 and sodium carbonate had obvious synergistic effect,can effectively decrease the oil-water interfacial tension.There was synergic effect between the alkaline and the surfactant and the interfacial tension was reduced to10^-3mN/m.Therefore,the preferred JS-33 was selected as a surfactant component.The optimized formula had good thermal stability in 60 days.The chemical system had little viscosity reduction andinterfacial tension can be maintained at 10^-2mN/m after three times of adsorption by the sand grain.The ASP system can increase the oil recovery by 27.5%-30.6%.