Evaluation of Chemical Properties of Microemulsion and Experimental Study of Oil Displacement Mechanism

Polymer macromolecules are difficult to enter low permeability reservoirs due to the characteristics of narrow pore throat, serious reservoir heterogeneity and high injection pressure. At present, low permeability oil fields are mainly developed by water drive, and the recovery rate is low. Therefore, the microemulsion flooding technology of low permeability reservoir is studied in order to develop low permeability oilfield reasonably and efficiently. The results show that the interfacial tension of the three microemulsions can reach an ultra-low level, and the interfacial tension of the betaine microemulsion is the lowest, which is 0.0026 mN/m. The three microemulsions have particle size peaks between 0.08 μm and 0.1 μm, and can easily pass through low-permeability core pores. The microemulsion viscosity is 7.2,8.5,7.4 mPa·s, respectively, which has a good ability to reduce the water-oil mobility ratio. In terms of solubilization capacity, MSDDS microemulsion had the strongest solubilization capacity, reaching 11.7 mL/g, while TW-20 and ABSC-14 microemulsion solubilization parameters were 9.5mL/g and 10.6mL/g, respectively. When the temperature is higher than the turbidity point of nonionic surfactants, the microemulsions appear stratified turbidity. Due to its ultra-low interfacial tension and better solublization parameters, betaine microemulsion improved the recovery rate by 16.45%.