Analysis of oil recovery efficiency and optimal selection of different displacement media in Daqing tight oil reservoir

Improving the availability of crude oil is the primary problem in tight oil development. In this paper, displacement experiment and online nuclear magnetic resonance detection technology are combined to analyze the production characteristics and effects of crude oil injected into tight oil reservoirs by CO2, CH4, active water and formation water, and by comparing the gas-oil ratio, water cut and injection-production pressure difference of each displacement medium. In the process of tight oil reservoir development, the potential of different displacement media to improve the degree of production is determined, and the optimal displacement media is selected. The effect of CO2 injection in tight core samples in Fuyu area is the best, and the recovery degree reaches 60%. for reservoirs with a large proportion of pores less than 0.1 μm, CO2 flooding can achieve effective mobility; in reservoirs with a large proportion of pores above 1 μm, the displacement efficiency by formation water is higher than that of other media. It is expected that this study can provide support for the optimization of tight oil development plans.