CO₂-foam injection is a promising technology for reducing gas mobility and increasing trapping within the swept region in deep brine aquifers. In this work, a consistent thermodynamic model based on a combination of the Peng-Robinson equation of state (PR EOS) for gas components with an activity model for the aqueous phase is implemented to accurately describe the complex phase-behavior of the CO₂-brine system. The phase-behavior module is combined with the representation of foam by an implicit-texture (IT) model with two flow regimes. This combination can accurately capture the complicated dynamics of miscible CO₂ foam at various stages of the sequestration process. The Operator-Based Linearization (OBL) approach is applied to improve the efficiency of the highly nonlinear CO₂-foam problem by transforming the discretized nonlinear conservation equations into a quasi-linear form based on state-dependent operators. We first validate our simulation results for enhanced CO₂ dissolution in a small domain with and without the presence of a capillary transition zone (CTZ). Then a 3D unstructured reservoir is used to examine CO₂-foam behavior and its effects on CO₂ storage. Simulation studies show good agreement with analytical solutions in both cases with and without CTZ. Besides, the presence of a CTZ enhances the CO₂ dissolution rate in brine. Foam simulations show that foams can reduce gas mobility effectively by trapping gas bubbles and inhibit CO₂ from migrating upward in the presence of gravity, which in turn improves the sweep efficiency and opens the unswept region for CO₂ storage. In the long run (post-injection), with the increasing effects of dissolution, the mechanism of residual trapping, due to the presence of foam, may not be significant. This work suggests a possible strategy to develop an efficient CO₂ storage technology.

CO ₂泡沫注入是一种有前景的技术，可用于降低气体流动性并增加深层盐水层在扫掠区域内的捕集。在这项工作中，一个一致的热力学模型基于状态（PR EOS），用于与用于水相的活动模型气体成分的彭罗宾逊方程的组合被实现为准确地描述CO的复杂的相位行为₂ -盐水系统。通过具有两种流动状态的隐式纹理（IT）模型，将相行为模块与泡沫表示相结合。这种组合可以准确地捕获可混溶CO ₂的复杂动力学。在隔离过程的各个阶段产生泡沫。基于算子的线性化（OBL）方法通过基于状态依赖算子将离散的非线性守恒方程转换为准线性形式，从而提高了高度非线性的CO ₂泡沫问题的效率。我们首先验证我们的模拟结果在有和没有毛细管过渡区（CTZ）的情况下在小范围内提高CO ₂溶解度的结果。然后，使用3D非结构化储层检查CO ₂泡沫行为及其对CO ₂储存的影响。仿真研究表明，在有和没有CTZ的情况下，分析解决方案都具有很好的一致性。此外，CTZ的存在会提高CO ₂在盐水中的溶解速度。泡沫模拟显示，泡沫可以通过捕获气泡来有效降低气体流动性，并在重力存在下抑制CO ₂向上迁移，从而提高了清扫效率，并打开了未扫描的区域用于存储CO ₂。从长远来看（注射后），随着溶出度的增加，由于泡沫的存在，残留捕集的机理可能并不重要。这项工作提出了开发有效的CO ₂储存技术的可能策略。