文献类型：期刊文献

英文题名：Effect of confinement on the vapor-liquid-liquid three-phase equilibrium during CO2 utilization and sequestration in shale reservoirs

作者：Chen, Zhuo[1];Li, Ruixue[2,3];Du, Yifei[2];Ma, Shunting[2];Zhang, Xin[4];Shi, Jialin[5]

机构：[1]Univ Alberta, Dept Chem & Mat Engn, Edmonton, AB T6G 2V4, Canada;[2]Chengdu Univ Technol, Coll Energy, Chengdu 610059, Peoples R China;[3]Chengdu Univ Technol, State Key Lab Oil & Gas Reservoir Geol & Exploitat, Chengdu 610059, Peoples R China;[4]Univ Alberta, Sch Min & Petr Engn, Edmonton, AB T6G 1H9, Canada;[5]East China Univ Sci & Technol, Sch Chem & Mol Engn, State Key Lab Chem Engn, Shanghai 200237, Peoples R China

年份：2025

卷号：16

期号：3

起止页码：199

外文期刊名：ADVANCES IN GEO-ENERGY RESEARCH

收录：EI(收录号：20252618675187);WOS:【ESCI(收录号:WOS:001517750300002)】；

基金：Acknowledgements This study was supported by the project from National Natural Science Foundation of China (No. 52004040) .

语种：英文

外文关键词：carbon sequestration; three-phase equilibrium; shale reservoir; confinement effect; phase behavior; CO2 utilization

摘要：With the rising global energy demand, shale gas and oil emerge as pivotal resources. Recent innovations utilizing CO2 as an injectant can effectively enhance shale oil and gas recovery and facilitate CO2 storage within shale reservoirs. However, low-temperature CO2 injection may result in the coexistence of three hydrocarbon phases, while the abundant nanopores in shale formations also notably influence the phase behavior of reservoir fluids. To optimize shale oil recovery and CO2 sequestration in shale formations, it is a prerequisite for precisely capturing the effect of confinement on the phase behavior of reservoir fluids within nanopores during CO2 injection. In this work, we introduce a novel threephase vapor-liquid-liquid equilibrium calculation algorithm, which is designed to handle the unique phase behavior challenges presented by CO2 utilization and storage in shale reservoirs. To improve the robustness and efficiency, the proposed algorithm integrates a trust region-based stability test with a hybrid flash calculation algorithm that combines the Newton-Raphson and trust-region methods. Our thermodynamic model incorporates the capillarity effect and shifts in the critical points due to molecule-wall interactions, which are essential for accurate phase behavior simulation under confinement. Initial validations against experimental bulk phase data show promising results, and further investigations indicate that confinement alters three-phase vapor-liquid-liquid equilibria by suppressing two-phase and three-phase regions and shifting boundaries in the phase diagrams. The proposed algorithm not only advances our understanding of multiphase equilibrium in nanoporous media but also enhances the practicality of CO2 sequestration and improved oil recovery strategies in shale formations.