Lee Ji Ho, Cho Jinhyung, Lee Kun Sang
Korea National Oil Corporation, 305, Jongga-ro, Jung-gu, Ulsan, 44538, Republic of Korea.
Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
Sci Rep. 2020 Feb 7;10(1):2071. doi: 10.1038/s41598-020-59131-y.
In shale gas reservoirs, CH and CO have finite aqueous solubilities at high-pressure conditions and their dissolutions in water affect the determination of the original gas in place and the CO sequestration. In addition, the dissolution of CO decreases the pH of connate water, and the geochemical reactions may thus occur in carbonate-rich shale reservoirs. The comprehensive simulations of this work quantify the effects of aqueous solubility and geochemistry on the performance CO huff-n-puff process in shale gas reservoir. Accounting for the aqueous solubility of CH increases the initial natural gas storage and natural gas production. The effect of the aqueous solubility of CO enables to sequester additional CO via solubility trapping. Considering the geochemical reactions, the application of the CO huff-n-puff process causes the dissolution of carbonate minerals and increases the porosity enhancing the gas flow and the gas recovery. Incorporation of geochemistry also predicts the less CO sequestration capacity. Therefore, this study recommends the consideration of aqueous solubility and geochemical reactions for the accurate prediction of gas recovery and CO sequestration in shale gas reservoirs during the CO huff-n-puff process.
在页岩气藏中，CH和CO在高压条件下具有有限的水溶度，它们在水中的溶解会影响原始气藏气量的确定以及CO的封存。此外，CO的溶解会降低原生水的pH值，因此在富含碳酸盐的页岩气藏中可能会发生地球化学反应。本研究的综合模拟量化了水溶度和地球化学对页岩气藏中CO吞吐过程性能的影响。考虑CH的水溶度会增加初始天然气储量和天然气产量。CO水溶度的影响使得能够通过溶解捕集封存额外的CO。考虑地球化学反应，CO吞吐过程的应用会导致碳酸盐矿物溶解并增加孔隙度，从而提高气体流动和气体采收率。纳入地球化学因素还预测了较低的CO封存能力。因此，本研究建议在CO吞吐过程中考虑水溶度和地球化学反应，以便准确预测页岩气藏中的气体采收率和CO封存情况。
