Understanding nanoconfined water effect on CO₂ utilization and storage has tremendous implications in academic research and practical applications, especially for extremely low‐permeability shale reservoirs. Here, a new nanoscale‐extended cubic‐plus association equation of state is developed by including the confinement effects and intermolecular interactions, based on which the phase behavior and interfacial tension of the pure water and water‐CO₂ system are accurately calculated. Moreover, three important parameters, caprock‐sealing pressure, maximum storage height, and storage capacity, are quantitatively determined for assessing the potential for the CO₂ storage. On the basis of the results from this study, the negative effect of nanoconfiend water can be substantially reduced or even converted to be positive for the CO₂ utilization and storage in the shale reservoirs due to the extremely small pore scale as well as the associated strong confinements and intermolecular interactions. Overall, this study supports the foundation of general practical applications pertaining to CO₂ utilization and geological storage in unconventional low‐permeability shale formations with existence of nanoconfined water.

中文翻译：

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纳米约束水对二氧化碳利用和地质封存的影响

了解纳米约束水对CO ₂利用和存储的影响在学术研究和实际应用中具有重大意义，尤其是对于渗透率极低的页岩储层。在这里，通过包含约束效应和分子间相互作用，开发了一个新的纳米级扩展的立方加缔合状态方程，在此基础上，可以精确计算纯水和水-CO ₂系统的相行为和界面张力。此外，定量确定了三个重要参数，即盖层密封压力，最大存储高度和存储容量，以评估CO ₂的潜力。存储。根据这项研究的结果，由于孔隙尺寸极小，并且伴有强烈的纳米级水，纳米级自给水的负面影响可以显着降低，甚至转化为对页岩储层中CO ₂利用和储存的积极影响。限制和分子间的相互作用。总的来说，这项研究为存在纳米约束水的非常规低渗透页岩地层中有关CO ₂利用和地质封存的一般实际应用奠定了基础。