Investigating the Influence of Pore Shape on Shale Gas Recovery with CO<sub>2</sub> Injection Using Molecular Simulation
Juan Zhou,
Shiwang Gao,
Lianbo Liu,
Tieya Jing,
Qian Mao,
Mingyu Zhu,
Wentao Zhao,
Bingxiao Du,
Xu Zhang,
Yuling Shen
Affiliations
Juan Zhou
National Key Laboratory of High-Efficiency Flexible Coal Power Generation and Carbon Capture Utilization and Storage, Huaneng Clean Energy Research Institute, Beijing 102209, China
Shiwang Gao
National Key Laboratory of High-Efficiency Flexible Coal Power Generation and Carbon Capture Utilization and Storage, Huaneng Clean Energy Research Institute, Beijing 102209, China
Lianbo Liu
National Key Laboratory of High-Efficiency Flexible Coal Power Generation and Carbon Capture Utilization and Storage, Huaneng Clean Energy Research Institute, Beijing 102209, China
Tieya Jing
National Key Laboratory of High-Efficiency Flexible Coal Power Generation and Carbon Capture Utilization and Storage, Huaneng Clean Energy Research Institute, Beijing 102209, China
Qian Mao
Institute of Technology for Nanostructures, University Duisburg-Essen, 47057 Duisburg, Germany
Mingyu Zhu
National Key Laboratory of High-Efficiency Flexible Coal Power Generation and Carbon Capture Utilization and Storage, Huaneng Clean Energy Research Institute, Beijing 102209, China
Wentao Zhao
National Key Laboratory of High-Efficiency Flexible Coal Power Generation and Carbon Capture Utilization and Storage, Huaneng Clean Energy Research Institute, Beijing 102209, China
Bingxiao Du
Huaneng Daqing Thermal Power Co., Ltd., Ranghulu District, Daqing 163159, China
Xu Zhang
Huaneng Daqing Thermal Power Co., Ltd., Ranghulu District, Daqing 163159, China
Yuling Shen
Huaneng Daqing Thermal Power Co., Ltd., Ranghulu District, Daqing 163159, China
Carbon-dioxide-enhanced shale gas recovery technology has significant potential for large-scale emissions reduction and can help achieve carbon neutrality targets. Previous theoretical studies mainly focused on gas adsorption in one-dimensional pores without considering the influence from the pore geometry. This study evaluates the effects of pore shape on shale gas adsorption. The pure and competitive gas adsorption processes of CO2 and CH4 in nanopores were investigated using molecular simulations to improve the prediction of shale gas recovery efficiency. Meanwhile, quantitative analysis was conducted on the effects of the pore shape on the CO2-EGR efficiency. The results indicate that the density of the adsorption layer in pores is equally distributed in the axial direction when the cone angle is zero; however, when the cone angle is greater than zero, the density of the adsorption layer decreases. Smaller cone-angle pores have stronger gas adsorption affinities, making it challenging to recover the adsorbed CH4 during the pressure drawdown process. Concurrently, this makes the CO2 injection method, based on competitive adsorption, efficient. For pores with larger cone angles, the volume occupied by the free gas is larger; thus, the pressure drawdown method displays relatively high recovery efficiency.
