中文摘要：

对于低渗透油藏，通过分析CO2注入井的井底压力双对数曲线特征，可以有效评价CO2混相驱的开发效果，但低渗透油藏存在强应力敏感效应，将会影响解释结果的可靠性，目前考虑应力敏感的CO2混相驱试井模型较少。基于三区复合油藏渗流理论，设计考虑应力敏感效应的CO2混相驱物理模型，并建立试井模型，从而获得井底压力的双对数曲线特征。结果表明：CO2混相驱试井模型曲线分为5个渗流阶段；应力敏感效应使得整个CO2混相驱试井曲线特征不再遵循0.5M规则，试井曲线后期出现较明显的上翘；CO2注入井井筒储集系数过高，纯CO2径向流阶段逐渐消失；流度比、各区驱替前缘半径将对整个CO2混相驱的渗流过程产生较大影响。试井模型应用于CO2注入井，能够准确确定纯CO2区和过渡区驱替前缘半径及其他相关参数，提高低渗透油藏CO2混相驱相关参数的解释精度。

英文摘要：

Analyzing the double logarithm curve characteristics of bottom hole pressure from CO2injection well is an efficient method to evaluate the performance of CO2miscible flooding in the low-permeability reservoirs.Strong stress sensitivity exists in the low-permeability reservoirs,which will affect the reliability of interpretation results.However,there is no report about well test model with the consideration of stress sensitivity.Based on the percolation theory of three-region composite reservoirs,physical model and well test model of CO2miscible flooding considering the stress sensitivity were established to know the double logarithm curve characteristics of bottom hole pressure.The results present that the well test model curve of CO2miscible flooding can be divided into five flow regions.The stress sensitivity makes the well test curve no longer follow the rule of0.5M,and the well test curve will appear obvious upward trend in the late stage.The higher wellbore storage coefficient will cover the pure CO2radial flow region.Mobility ratio and displacement front radius play an important role in the process of CO2miscible flooding.This model was applied to the CO2injection well.The displacement front radius and other relevant parameters in pure CO2region and transition region can be accurately determined,and the interpretation accuracy of the relevant parameters of CO2miscible flooding in the low-permeability reservoir may be improved.