OIL DISPLACEMENT TEST RESEARCH ON SURFACTANT-POLYMER SYSTEM

ASP cooperates alkali, surfactant and polymer to flood oil reserves. It can produce a ultra low interfacial tension to oil with very low concentration of surfactant, and improve displacement efficiency largely; it enhance producible oil recovery factor largely. ASP experiment practice in Daqing Oilfield had gotten preferable effect, which enhanced producible oil recovery factor by 20%.But during the practical use of ASP,some questions follow. Among them the most severe effect on oil and formation is that alkali can lower formation permeability because it can scrap formation clay and make them move and can form alkali scale, Alkali can lower largely viscoelasticity of polymer.As a result sweeping volume is lowered because of viscidity fingering. To surfactant-polymer system, in order to improve the oil recovery efficiently, a kind of better surfactant need be found. According to the request of interfacial tension attaining to 10-2 mN/m in surfactant-polymer system, NEP system had been researched that has low interfacial tension and get rid of scale effect on viscoelasticity of flooding system. Its last producible oil index may equal that of APS. After experimental study, it has been concluded that new surfactant-polymer system can enhance producible oil recovery factor by 20%.