Coupling Mechanism of CO<sub>2</sub> Adsorption and Pore Deformation in Shale Kerogen with Different Maturities

HUANG Liang; TIAN Baohua; XU Zhenyao; CHEN Qiujie; FENG Xinni; ZHU Haiyan; YANG Qin; ZHANG Runfeng; WANG Bowen

doi:10.6054/j.jscnun.2025008

Journal of South China Normal University (Natural Science Edition) > 2025 > 57(1): 70-78. > DOI: 10.6054/j.jscnun.2025008

HUANG Liang, TIAN Baohua, XU Zhenyao, CHEN Qiujie, FENG Xinni, ZHU Haiyan, YANG Qin, ZHANG Runfeng, WANG Bowen. Coupling Mechanism of CO₂ Adsorption and Pore Deformation in Shale Kerogen with Different Maturities[J]. Journal of South China Normal University (Natural Science Edition), 2025, 57(1): 70-78. DOI: 10.6054/j.jscnun.2025008

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Coupling Mechanism of CO₂ Adsorption and Pore Deformation in Shale Kerogen with Different Maturities

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation/College of Energy(College of Modern Shale Gas Industry), Chengdu University of Technology, Chengdu 610059, China

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Received Date: November 18, 2024

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Abstract

Abstract

The adsorption of CO₂ in shale kerogen results in the pore deformation, which, in turn, affects the adsorption capacity of kerogen. The coupling characteristics and micro-mechanisms between CO₂ adsorption and pore deformation in shale kerogen remain unclear. For kerogen with different maturities, this study systematically simulated CO₂ adsorption behavior under various strains and pressures using molecular simulation methods. Building on this, the coupling coefficient between CO₂ adsorption and pore deformation in shale kerogen was quantified through poromechanical theory, uncovering its dynamic volution with kerogen maturity. Additionally, the micro-mechanisms of adsorption-deformation coupling were clarified by examining the evolution of kerogen pore structures and their non-bonded interactions (e.g., van der Waals and electrostatic forces) with CO₂. The findings show that the coupling coefficient between CO₂ adsorption and pore deformation in shale kerogen is maturity-dependent, and results derived from coal organic matter are not directly transferable. Furthermore, the adsorption-deformation capacity of kerogen diminishes as maturity increases. The coupling coefficient is approximately constant within a certain pressure range (>2 MPa), and significant differences are observed in the coupling coefficients for immature kerogen during its compression and expansion stages. The adsorption interaction of CO₂ on kerogen is mainly controlled by van der Waals forces, followed by electrostatic forces. The adsorption of CO₂ increases the porosity and specific surface area of kerogen and induces a shift towards larger pore sizes in the pore size distribution. The results reveal the coupled characteristics and micro-mechanisms between CO₂ adsorption and pore deformation in shale kerogen, which provide theoretical guidance for evaluating the performance of CO₂ sequestration in shale reservoirs.
- shale kerogen,
- CO₂ adsorption,
- pore deformation,
- coupling effect,
- molecular simulation

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References (24)

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