CO dissolution reactions in saline aquifers during geologic carbon sequestration (GCS) involve multiple physicochemical processes and pose a challenge for both experimental and numerical techniques to capture reactive transport features and complex porous structures. Benefited from advanced models in the lattice Boltzmann (LB) community, namely, multiphase flow LB model and multicomponent transport LB model with chemical reactions, dynamics of CO-water interfaces, concentration evolution of ions, and heterogeneous and homogeneous reactions could be readily captured by the proposed LB model to characterize CO dissolution reactions applicable to far-field applications. This LB model can not only emphasize CO dissolution processes at the scale of a few pores but also elaborate on the corresponding controlling mechanisms in porous media during GCS in saline aquifers. LB simulations herein indicate that both diffusion coefficient and reactive interfacial length may change the total concentration gradient at the CO-water interface to further affect CO dissolution reactions. It is also confirmed that CO dissolution is a non-equilibrium process, which could not be neglected in reservoir-scale simulations. The effect of reactive interfacial length on CO dissolution is negligible due to a narrower range of contact angles in saline aquifers. Influenced by the structural complexity of porous media, the dissolution of CO clusters shows a strong heterogeneous characteristic evaluated by the pore size distribution. The evolution of pH in homogeneous reactions is estimated via mass action equations. Besides, the effects of partial pressure, formation temperature, and salinity, as three key factors in the practical application, are thoroughly probed. The high pressure is conducive for sequestration because of its greater sequestration efficiency, but the temperature has both positive and negative impacts on CO dissolution trapping and should be carefully evaluated in a certain saline aquifer before the operation. High ion strength would decrease the efficiency of dissolution trapping to some extent.

中文翻译：

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利用格子玻尔兹曼法模拟盐水层中 CO2 溶解反应

地质碳封存 (GCS) 期间咸水层中的 CO 溶解反应涉及多种物理化学过程，对捕获反应传输特征和复杂多孔结构的实验和数值技术提出了挑战。受益于格子玻尔兹曼 (LB) 界的先进模型，即具有化学反应的多相流 LB 模型和多组分传输 LB 模型，CO-水界面动力学、离子浓度演化以及非均相和均相反应可以通过提出的 LB 模型用于表征适用于远场应用的 CO 溶解反应。该LB模型不仅可以强调少数孔隙尺度上的CO溶解过程，而且可以详细阐述咸水层GCS过程中多孔介质的相应控制机制。本文的 LB 模拟表明，扩散系数和反应界面长度都可能改变 CO-水界面处的总浓度梯度，从而进一步影响 CO 溶解反应。还证实了CO溶解是一个非平衡过程，在油藏规模模拟中不可忽视。由于盐水含水层中的接触角范围较窄，反应界面长度对 CO 溶解的影响可以忽略不计。受多孔介质结构复杂性的影响，CO团簇的溶解表现出强烈的非均质特征，通过孔径分布来评价。均相反应中 pH 值的变化通过质量作用方程进行估计。此外，还深入探讨了分压、地层温度和盐度这三个实际应用中的关键因素的影响。高压因其封存效率较高而有利于封存，但温度对CO溶解捕集既有积极的影响，也有消极的影响，在操作前应在一定的咸水层中仔细评估。高离子强度会在一定程度上降低溶解捕获效率。