Research And Application On Depressurizing And Stimulation Mechanism Of The Surfactant

The reserves of low permeability reservoir in Linpan Oil Production Plant are very big, but it is clastic reservoir with low porosity, extra low permeability and high degree of mineralization., because of the influence of acid-sensitive mineral in the layer, the longevity of acidizing treatment in these wells is short and it cannot solve the problem thoroughly.In view of the geologic condition of Xia502 block of Jiangjiadian Oilfield, the compatibility experiments of ten kinds of normal surface active agents and injected water initially selected the right surface active agent which suited the high degree of mineralization condition of Jiangjiadian Oilfield. Moreover , the surface active agent combination experiments with measuring the surface tension selected the assist agent and the combination optimum concentration and finally ascertained the surface active agent stimulation combination system with extra low interfacial tension. The system could endure high temperature and high degree of mineralization and maintain the of extra low interfacial tension. The research and experiment of the filtering flow property and alteration mechanism of oil and gas of low permeable reservoir show that the system could decrease interfacial tension of oil and gas by a wide margin, widen two-phase cocurrent flow area and decrease the residual oil saturation. Moreover, the relative permeability of oil and gas got higher, especially the water phase permeability got higher rapidly and the final value was much higher. The hydrophilcity of rock was much stronger and injecting low interfacial tension water with active agent could decrease the interfacial tension of oil and gas and raise the relative permeability of injected water. Finally, it realized the goal of decreasing staring pressure. The experiment at the well site showed that water injection rate increased by 10～15m3/d when the injection pressure decreased by 3～4MPa or was unchangeable. Developing the research of stimulation technology of low permeable or extra low permeable reservoirs not only values theoretically but also has practical value for developing active water drive and raise the final recovery efficiency of low permeable reservoirs.