CO₂ injection into underground formations can reduce CO₂ emissions, enhance hydrocarbon and methane recovery, and extract geothermal heat. As the pressure and temperature vary in subsurface formations, the injected CO₂ can be in gas, liquid and supercritical phase. The change in CO₂ phase is likely to have a significant impact on capillary and viscous forces, which, in turn, will have a considerable influence on injectivity, displacement, migration, storage capacity and integrity of CO₂ processes. This study was designed to investigate the effect of CO₂ phase, at different injection rates, on the dynamic pressure evolution and the CO₂ displacement performance during CO₂ injection into a water-saturated sandstone core sample. The results indicate that CO₂ phase significantly affects the differential pressure profile and water production profile. The differential pressure profiles measured from the displacement of supercritical CO₂ and gas CO₂ were significantly different from those measured from liquidCO₂ displacements, particularly before CO₂ breakthrough. Gas and supercriticalCO₂ injection gave a water production rate much higher than the CO₂ injection rate at early stages. Liquid CO₂ injection yielded a water production rate similar to the CO₂ injection rate. This may indicate that the injection of ScCO₂or GCO₂ (under a pressure higher than 60 bar) could give a high and quick oil production rate. The highest water recovery was obtained after the injection of 0.85, 1.08 and 2.32 pore volumes of scCO₂, gCO_2, and LCO₂, respectively. The residual water saturations for the three CO₂ phases were in the range of 30–33% while the endpoint relative permeability was in the range of 18–21%. The endpoint relative permeabilities for gas and liquid CO₂ were very similar and higher than that of supercritical CO₂ under our experimental conditions. The increase in injection rate caused a slight increase in the endpoint relative permeabilities for the three CO₂ phases.

将CO ₂注入地下地层可以减少CO ₂排放，提高碳氢化合物和甲烷的回收率，并提取地热。随着地下地层中压力和温度的变化，注入的CO ₂可以处于气相，液相和超临界相。CO ₂相的变化可能会对毛细作用力和粘性作用力产生重大影响，进而对毛细作用力，位移，迁移，储存能力和CO ₂过程的完整性产生重大影响。本研究旨在探讨CO的作用₂阶段，在不同的注射速率，在动态压力变化和CO ₂将CO ₂注入含水饱和砂岩岩心样品中时的驱油性能。结果表明，CO ₂相显着影响压差曲线和产水曲线。从超临界CO的位移测量的差分压力曲线₂和气体CO ₂是从那些从测量liquidCO不同显著₂的位移，特别是前CO ₂突破。气体和supercriticalCO ₂注射给予了水的生产速度比CO高得多₂在早期喷射率。液态CO ₂注入产生的产水速率与CO ₂注入速率相似。这可能表明注入ScCO ₂或GCO ₂（在高于60 bar的压力下）可以提供高而快速的产油率。的SCCO 0.85，1.08和2.32孔体积在注射后获得的最高水回收₂，GCO _2，和LCO ₂分别。三个CO ₂相的残留水饱和度在30–33％的范围内，而终点相对渗透率在18–21％的范围内。气体和液体CO ₂的端点相对磁导率非常相似，并且高于超临界CO _2的相对磁导率。在我们的实验条件下。注入速率的增加导致三个CO ₂相的终点相对渗透率略有增加。