CO₂ sequestration into saline aquifers has been demonstrated as an effective technique to mitigate the effects of carbon dioxide on the atmosphere. The displacement mechanism during this process has not been clarified and the two-phase immiscible flow is affected by many factors. In this study, two types of homogeneous micromodels with circular and square cross sections were used to investigate the pore-scale of residual and capillary trapping at 25 ℃ and ambient pressure. Two salinities and six injection rates were used to study their impacts on CO₂ saturation. Drainage experiments were conducted using a high-resolution microscope and a camera. The CO₂ saturation and its distribution are investigated using image processing. Three forms of wetting phases are observed in circular grains, whereas additional special forms are observed in square grains, and these existing forms of the wetting phase are applied for mechanism analysis. Changes in the tortuosity and wettability are also analyzed to clarify why the saturation in the micromodel with square cross section was higher than that of circular cross section. The displacement pattern, the injection rate, the salinity, and the micromodel structure all have impacts on CO₂ displacement efficiency and safe sequestration.

事实证明，将CO ₂封存到盐水层中是减轻二氧化碳对大气影响的有效技术。该过程中的位移机理尚未阐明，两相不混溶流受许多因素影响。在这项研究中，使用两种类型的具有圆形和正方形横截面的均质微模型来研究在25℃和环境压力下残留和毛细管捕集的孔径。使用两种盐度和六种注入速率来研究它们对CO ₂饱和度的影响。使用高分辨率显微镜和照相机进行排水实验。一氧化碳₂使用图像处理研究饱和度及其分布。在圆形晶粒中观察到了三种形式的润湿相，而在方形晶粒中观察到了其他特殊形式，并且将这些现有的润湿相形式用于机理分析。还分析了曲折度和润湿性的变化，以弄清为什么具有正方形横截面的微模型的饱和度高于圆形横截面的饱和度。驱替模式，注入速率，盐度和微模型结构都对CO ₂驱替效率和安全隔离产生影响。