This study focused on the effects of the CO phase on the formation mechanisms of residual water. Based on nine groups of core-flooding experiments, the order of residual water saturation was gaseous CO > supercritical CO > liquid CO, and a quantitative power function relationship between residual water saturation and displacement time for different CO phases was proposed. The experimental results show that when CO transitions from the gaseous phase to the supercritical phase and then to the liquid phase, the decrease in the interfacial tension and cosine value of the contact angle in two-phase flow can lead to a decrease in residual water saturation. Meanwhile, an increase in the viscosity ratio of two-phase flow weakens the viscous fingering phenomenon and can also lead to a decrease in residual water saturation. However, the log-log stability phase diagram reveals that the viscous force is the primary factor influencing all core-flooding experiments.

中文翻译：

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CO2-水-岩石系统中残余水的形成机制：CO2相的影响


本研究的重点是CO相对残余水形成机制的影响。基于9组岩心驱油实验，残余水饱和度大小顺序为气态CO>超临界CO>液态CO，并提出了不同CO相残余水饱和度与驱替时间之间的定量幂函数关系。实验结果表明，当CO由气相过渡到超临界相再过渡到液相时，两相流界面张力和接触角余弦值的减小会导致残余水饱和度的降低。同时，两相流粘度比的增加减弱了粘性指进现象，也会导致残余水饱和度降低。然而，双对数稳定性相图表明，粘性力是影响所有岩心驱油实验的主要因素。