Carbon geo-sequestration is a promising method for mitigating global warming and climate change. Depleted shale gas reservoirs with high adsorption capacities, excellent sealing properties, and complete infrastructure are potential sites for CO2 storage. However, hydraulic fracturing and extensive CO2 injection can result in fault reactivation, leading to CO2 migration and an increased risk of environmental contamination. Given this problem, a partially permeable boundary is introduced to characterize permeable faults. Herein, a novel methodology based on rate transient analysis that considers CO2 adsorption, diffusion, and leakage is proposed for evaluating the CO2 storage capacity of depleted shale gas reservoirs. The analytical solution for a multiple fractured horizontal well with finite conductivity is derived from the principle of potential superposition, Laplace transform, and correction functions. Subsequently, according to the analytical solutions, a rapid and robust CO2 storage capacity assessment technique is established. Using field data of the Marcellus shale, a sensitivity analysis is performed to analyze the effects of the reservoir and well parameters on the injection performance, carbon storage potential, and CO2 leakage risk. The results indicate that the proposed model is consistent with previously reported semi-analytical models and numerical simulations. The injection rate and cumulative leakage ratio increase with the leakage ratio, resulting in gas migration and an increased risk of leakage. Reservoirs with large drainage radii, high Langmuir volumes, and small Langmuir pressures are suitable for carbon sequestration, significantly increasing the adsorption capacity and reducing the leakage risk. In this study, a novel method is used to calculate the analytical solution for multiple fractured horizontal wells, which allows a rapid and practical CO2 geo-sequestration capacity assessment for CO2 storage projects.

碳地缘封存是缓解全球变暖和气候变化的一种很有前景的方法。具有高吸附能力、优异的密封性能和完整的基础设施的枯竭页岩气藏是 CO2 储存的潜在场所。然而，水力压裂和大量的二氧化碳注入会导致断层重新激活，导致二氧化碳迁移并增加环境污染的风险。鉴于此问题，引入部分可渗透边界来表征可渗透断层。在此，提出了一种基于速率瞬态分析的新方法，该方法考虑了 CO2 的吸附、扩散和泄漏，用于评估枯竭页岩气储层的 CO2 储存能力。具有有限导流能力的多裂缝水平井的解析解是根据电位叠加原理、拉普拉斯变换和校正函数推导出来的。随后，根据分析解决方案，建立了一种快速、稳健的二氧化碳储存能力评估技术。利用 Marcellus 页岩的现场数据，进行敏感性分析，分析储层和井参数对注入性能、碳储存潜力和 CO2 泄漏风险的影响。结果表明，所提出的模型与先前报道的半解析模型和数值模拟一致。注入率和累积泄漏率随着泄漏率的增加而增加，导致气体迁移和泄漏风险增加。排水半径大的水库，高朗缪尔体积和小朗缪尔压力适合碳封存，显着提高吸附能力并降低泄漏风险。在这项研究中，使用一种新方法来计算多口压裂水平井的解析解，从而可以对 CO2 封存项目进行快速实用的 CO2 地质封存能力评估。