Study on micro-utilization of CO2 drive in long core of Jilin ultra-low permeability reservoir
In order to solve the problem related to the difficulty in the utilization of the ultra-low permeability reservoir in Moliqing oilfield,Songliao Basin,the study of CO2 displacement of long core was carried out by using the experimental method of physical simulation experiment and nuclear magnetic resonance technology.The results show that CO2 displacement efficiency of rock samples ranges from 72.30%to 80.40%.The average occurrence ratio of macropore throat(>33 ms)is 33.65%,and that of micropore throat(<33 ms)is 18.01%.After CO2 displacement with a flow volume of 1 PV,the average relative recovery degree of macropore throat is 80.67%and the average relative recovery degree of small pore throat is 17.45%.After CO2 displacement with a flow volume of 5 PV,the average relative recovery degree of macropore throat is 95.68%,and the average relative recovery degree of small pore throat is 39.82%.A larger PV displacement can effectively use the oil of small pore throat.The research results can provide theoretical support for CO2 displacement in Moriqing oilfield,and also provide scientific guidance for pilot gas injection test in similar reservoirs.
ultra-low permeability reservoirnuclear magnetic resonanceCO2 floodingdegree of recovery
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