Xu, Feng (SOUTHWEST PETROLEUM UNIVERSITY) | Guo, Xiao (the State Key Lab of Oil and Gas Reservoir Geology and Exploitation) | Wang, Wanbin (the State Key Lab of Oil and Gas Reservoir Geology and Exploitation) | Zhang, Nan (the State Key Lab of Oil and Gas Reservoir Geology and Exploitation) | Jia, Sa (the State Key Lab of Oil and Gas Reservoir Geology and Exploitation) | Wang, Xiaoqin
Low permeability reservoir occupies an important position in China's petroleum industry, as an important oil industry resource over a period of time in future, which helps to increase reserves and production. Surfactant flooding is one of the most effective ways to improve development effect in the low permeability reservoirs, which can reduce the injection pressure and increase injection rate, thereby enhancing oil recovery. Common mechanisms that how the surfactants enhance oil recovery are discussed in the paper. On the basis of assumptions, a seepage model of surfactant flooding was built to describe the complex process. Experiments was done to determine the surfactant's performance, such as the relationship between surfactant concentration and oil/water interfacial tension, the relationship between surfactant concentration and rock adsorbance, and the relationship between surfactant concentration and water viscosity. Take the Yanchang low permeability reservoir for example, where the study of surfactant flooding is conducted after the optimal water injection plan to evaluate the effect of different surfactant concentration on the development results in the low permeability reservoir. The simulation results show that surfactant flooding has the role of enhancing oil recovery, and that the optimal surfactant concentration is 2%, which can enhance oil recovery by the percentage of 0.22.