Study On Displacement Effect Factors Of Surfactant-polymer System And Method Of Mobility Control After Polymer Flooding

After polymer flooding, there are still a lot of remaining oil has not been taken out of the oil layer, surfactant-polymer flooding is an important technology to improve recovery after polymer flooding. The potential for enhanced oil recovery is limited by using common method of surfactant-polymer flooding. Combined with method of mobility control,surfactant-polymer flooding can further improve the Swept volume and displacement efficiency. Therefore, it is a great significance to study the displacement effect factors of surfactant-polymer system and the method of mobility control after polymer flooding.In this paper, based on the study on mechanism of surfactant-polymer flooding, using Eclipse numerical simulation software to explore the effect of variation coefficient on oil displacement and distribution of remaining oil after polymer flooding. The results showed that:the higher the variation coefficient, the worse the polymer flooding effect, the remaining oil is concentrated in lower permeability layer.The displacement effect factors of surfactant-polymer system are studied for reservoir of variation coefficient is 0.72. The results showed that: the effect of flooding is affected by the injection of the polymer solution concentration, the inter-facial tension of system, Injection volume, the coefficient of variation and injection time. The injection rate of system has little effect on surfactant-polymer flooding after polymer flooding.Based on two parallel cores experiments, the permeability contrast of 1: 5 and 1:10heterogeneous model are established. Based on the basic idea of mobility designs, the mobility control scheme of slug combination of a high concentration of polymer and surfactant-polymer systems is designed. The main principle of the mobility control scheme is that high concentration polymer solution is firstly injected to block the high permeability layer so that improve the Swept volume, then the subsequent solution can be injected into the low-permeability layer, start the remaining oil in low permeability layer, thereby improving recovery. Combined with the results of numerical simulation, the optimum scheme is optimized.