Taking the cores of extra-low-permeability reservoir in Jilin Oilfield as example, the long core oil-flooding experiments are engaged for different flooding programs. The studies show that when the gas-water ratio is 2: 1 , the maximum ultimate recovery (60. 45% ) can be realized and the minimum ultimate recovery of the water flooding is 39. 56%. The relation between the experimental ultimate recoveries for different gas-water ratios and the CO2 volume proportion to the total injected fluid are positively correlated; and furthermore the water breakthrough times for different displacing experiments are not the same. The gas-water alternating injection can result in lagging behind of the water breakthrough times; when the gas is broken through, the injected volume of the gas is about 0. 2 PV. There is an accordant change trend in the total pressure gradients of water flooding and CO2 flooding experiments ; on the contrary, there is much seriously different in the change trends of the total pressure gradients for the experiments of 1: 1 and 1: 2 gas-water ratios comparing with the mentioned ratio(2: 1 GWR).%采用吉林油田特低渗透储层的岩心进行不同驱替方式的长岩心驱油实验.研究表明,气、水比为2∶1驱油实验的最终采收率最大(为60.45％),水驱油实验的最终采收率最小(为39.56％).不同气、水比驱油实验最终采收率与总注人流体中CO2所占体积比例呈正相关关系,不同驱替实验的见水时间不同.气、水的交替注入会导致见水时间滞后,产出端见气时的注入体积约为0.2倍孔隙体积.水驱油和CO2驱油实验的总压力梯度的变化趋势较一致,气、水比为1∶1和1∶2驱油实验与气、水比2∶1驱油实验的总压力梯度的变化趋势差别较大.
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