Civil and Environmental Engineering, University of Virginia , Thornton Hall, 351 McCormick Road, Charlottesville, Virginia 22904, United States.
Environ Sci Technol. 2013 Oct 1;47(19):11318-25. doi: 10.1021/es401221j. Epub 2013 Sep 23.
Hydraulically fractured shale formations are being developed widely for oil and gas production. They could also represent an attractive repository for permanent geologic carbon sequestration. Shales have a low permeability, but they can adsorb an appreciable amount of CO2 on fracture surfaces. Here, a computational method is proposed for estimating the CO2 sequestration capacity of a fractured shale formation and it is applied to the Marcellus shale in the eastern United States. The model is based on historical and projected CH4 production along with published data and models for CH4/CO2 sorption equilibria and kinetics. The results suggest that the Marcellus shale alone could store between 10.4 and 18.4 Gt of CO2 between now and 2030, which represents more than 50% of total U.S. CO2 emissions from stationary sources over the same period. Other shale formations with comparable pressure-temperature conditions, such as Haynesville and Barnett, could provide significant additional storage capacity. The mass transfer kinetic results indicate that injection of CO2 would proceed several times faster than production of CH4. Additional considerations not included in this model could either reinforce (e.g., leveraging of existing extraction and monitoring infrastructure) or undermine (e.g., leakage or seismicity potential) this approach, but the sequestration capacity estimated here supports continued exploration into this pathway for producing carbon neutral energy.
水力压裂页岩地层正在被广泛开发用于石油和天然气生产。它们也可能成为永久性地质碳封存的一个有吸引力的储存库。页岩的渗透率很低，但它们可以在裂缝表面吸附相当数量的二氧化碳。在这里，提出了一种估算裂缝页岩地层二氧化碳封存能力的计算方法，并将其应用于美国东部的马塞勒斯页岩。该模型基于历史和预测的 CH4 产量，以及 CH4/CO2 吸附平衡和动力学的已发表数据和模型。结果表明，仅马塞勒斯页岩就可以在现在到 2030 年之间储存 104 到 184 亿吨的二氧化碳，这超过了同期美国固定源二氧化碳排放量的 50%以上。其他具有类似压力-温度条件的页岩地层，如海恩斯维尔和巴尼特，可能提供更大的储存能力。传质动力学结果表明，二氧化碳的注入速度将比 CH4 的产量快几倍。本模型未包含的其他因素可能会加强（例如，利用现有的提取和监测基础设施）或破坏（例如，泄漏或地震潜力）这种方法，但这里估计的封存能力支持继续探索这种生产碳中和能源的途径。
