ABSTRACT
For reservoirs entering the middle and late stage of development, there is still a large amount of residual oil remaining in the reservoir after water flooding, and CO2 flooding has been widely used as the main enhanced oil recovery technology at this time. To clear the interface characteristics and interaction relationship of oil-gas-water under high temperature and high pressure. The microscopic influencing factors of interfacial tension are analyzed and the mining effect of CO2 flooding in the late stage of high water cut reservoir is revealed. Axisymmetric drop shape analysis (ADSA) method has been used to measure the interfacial features of oil-gas, oil-carbonated water and oil-water system under the simulated-formation condition. The influence of density of medium, intermolecular force and interfacial tension of various physical parameters are analyzed from the microscopic point of view. The effects of two-phase density difference, intermolecular force and interfacial tension of various physical quantities of oil-water are analyzed. In the oil-CO2 system, the main factors affecting the interfacial tension are the density difference between two phases and the intermolecular force. In the oil-saturated carbonate system, the intermolecular force, the shape factor of suspended droplets and the square value of the maximum diameter of suspended droplets are the main factors to reduce the interfacial tension.
