Enhanced oil recovery (EOR) processes are unavoidable fact, which will be applied in oil upstream industry. It seems the miscible gas injection into oil reservoirs be one of the most effective methods in EOR approaches. Therefore, the interfacial mass transfer and dead end pore flooding of carbon dioxide miscibility flooding take part an important role in oilfield. This study is mainly conducted by reservoir flow and supercritical fluid theory. Supercritical CO2 miscible flooding mechanism and a special dead end displacement mechanism are studied in ultra-low permeability reservoir. Besides, supercritical CO2 micro-flow characteristics and mass transfer between oil and CO2 are analyzed. Using a high-speed advanced and visualization camera (5000/s) micro-simulation model, the flooding mechanism of transient dead end pore and interfacial mass transfer are both observed. The oil film migration phenomenon and the miscibility are also clarified. During the flooding, the wax in crude oil continues to deposit at pore throat to form transient dead end. Supercritical CO2 could flood the oil in dead end by the cylinder and the cylindrical flow. As existence of molecular coalesces in supercritical CO2, it has a strong ability to dissolve heavy crude oil. This study will provide a theoretical support for CO2 crude oil miscible flooding in pilot test of permeability reservoir.

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