Non-uniform matrix deformation reshaping fluid diffusion properties and its effect on the supervision assessment of CO2 safety sequestration

• Published in: Physics of fluids (1994) Vol. 37; no. 7
• Main Authors: Yang, Dahan, Xu, Wenxu, Liu, Zhengdong, Xu, Xinlei, Zhou, Dingbo, Bu, Naishun
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.07.2025
• Subjects: Carbon dioxide; Carbon sequestration; Coal; Deformation effects; Diffusion rate
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/5.0276006

The CO2 sequestration capacity of deep coalbeds is profoundly governed by the fluid diffusion properties. However, the role of non-uniform matrix deformation in reshaping diffusion pathways remains inadequately understood. This urgently requires attention to the effect of fluid diffusion behavior on CO2 sequestration under the control of non-uniform matrix deformation. Based on the non-uniform matrix deformation coefficient and integrating the multivariate physical property parameters of Shenmu Runbang coal samples, this study investigates the evolution of matrix width under the regulation of non-uniform matrix deformation. By elucidating the evolution characteristics of binary gas adsorption–desorption, gas concentration, and diffusion rate, this study reveals the mechanism by which non-uniform deformation influences fluid diffusion behavior. Furthermore, it clarifies the impact mechanism of fluid diffusion behavior on deep coal seam CO2 storage under the control of non-uniform matrix deformation characteristics. The findings reveal that the influence of non-uniform matrix deformation on matrix width exhibits the nonlinear characteristic of a significant biphasic transition, and it significantly attenuates the fluid diffusion within the matrix. Furthermore, binary gas-induced non-uniform matrix deformation significantly suppresses matrix width. In the process of CO2 sequestration in deep coal seams, this effect notably mitigates matrix swelling induced by CO2, thereby enhancing the dual regulatory role of matrix width and fracture aperture in diffusion capacity, and further enhances the positive effect of diffusion capacity on CO2 sequestration, providing theoretical support for the technological innovation of deep coal seam CO2 safety sequestration and effectively contributing to the realization of dual-carbon supervision assessment goals.