Evaluation on Adaptability of Medium Phase Microemulsion Flooding in C1 Reservoir of Wuliwan

With the development stage of medium and high water cut, The peak water intake in the profile of Wuliwan C1 reservoir is improved after weakened water, and water injection inrush is easy to lead to water flooding in small injection, but the proportion of non-suction well or weak suction well in the first interval section is high. The plane remaining oil is mainly distributed in the micro-seepage channel in the deep part of the reservoir and the water flooding is difficult. At the same time, the conventional measures are difficult to develop the remaining oil, and it is more difficult to further expand the swept volume after multiple rounds of microsphere flooding. Based on reservoir temperature, crude oil properties, formation water and produced water salinity composition in the test area, a lower medium phase microemulsion flooding system under the condition of high salinity was designed. The results show that the designed medium phase microemulsion system is composed of two surfactant complex, the volume ratio of the main surfactant A and the auxiliary surfactant B is 1:1, and the interfacial tension can reach 0.003 mN/m under the condition of 0.5% mass concentration, which has very low interfacial tension and good solubility. The swept volume of microsphere flooding was expanded, the oil washing efficiency was improved by the medium phase microemulsion flooding in the test area of Wuliwan C1 reservoir, which had an obvious effect on reducing water cut, and improved a new method for the effective use of remaining oil in the middle and high water cut reservoir.