Numerical analysis of matrix swelling and its effect on microstructure of digital coal and its associated permeability during CO_(2)-ECBM process based on X-ray CT data

作     者：Hui-Huang Fang Zhang-Fei Wang Shu-Xun Sang Yan-Hui Huang 

作者机构：School of Earth and EnvironmentAnhui University of Science and TechnologyHuainanAnhui232001China Institute of EnergyHefei Comprehensive National Science CenterHefeiAnhui230000China Low Carbon Energy InstituteChina University of Mining and TechnologyXuzhouJiangsu221008China School of Resources and GeosciencesChina University of Mining and TechnologyXuzhouJiangsu221116China Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and UtilizationChina University of Mining and TechnologyXuzhouJiangsu221008China State Key Laboratory of Petroleum Resources and ProspectingChina University of PetroleumBeijing102249China 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2023年第20卷第1期

页      面：87-101页

核心收录：

学科分类：0819[工学-矿业工程] 081903[工学-安全技术及工程] 08[工学] 

基　　金：This work was financially supported by the National Natural Science Foundation of China(No.42102217) the University Synergy Innovation Program of Anhui Province(No.GXXT-2021-018) the Natural Science Research Project of Anhui University(No.KJ2020A0315 No.KJ2020A0317) the Natural Science Foundation of Anhui Province(No.2108085MD134) the Foundation of State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing(No.PRP/open-2005) 

主　　题：Matrix swelling CO_(2)-ECBM Absolutely permeability Numerical analysis X-ray CT Qinshui Basin 

摘      要：Matrix swelling effect will cause the change of microstructure of coal reservoir and its permeability,which is the key factor affecting the engineering effect of CO_(2)-ECBM *** Sihe and Yuwu collieries are taken as research ***,visualization reconstruction of coal reservoir is ***,the evolution of the pore/fracture structures under different swelling contents is ***,the influence of matrix phase with different swelling contents on permeability is ***,the mechanism of swelling effect during the CO_(2)-ECBM process is further *** results show that the intra-matrix pores and matrix-edge fractures are the focus of this study,and the contacting area between matrix and pore/fracture is the core area of matrix *** number of matrix particles decreases with the increase of size,and the distribution of which is isolated with small size and interconnected with large *** swelling effect of matrix particles with larger size has a great influence on the pore/fracture *** number of connected pores/fractures is limited and only interconnected in a certain *** the increase of matrix swelling content,the number,porosity,width,fractal dimension,surface area and volume of pores/fractures decrease,and their negative contribution to absolute permeability increases from 0.368% to 0.633% and 0.868%-1.404%,*** the increase of swelling content,the number of intra-matrix pores gradually decreases and the pore radius becomes shorter during the CO_(2)-ECBM *** matrix continuously expands to the connected fractures,and the width of connected fractures gradually *** the influence of matrix swelling,the bending degree of fluid flow increases gradually,so the resistance of fluid migration increases and the permeability gradually *** study shows that the matrix swelling effect is the key factor affecting CBM recovery,and the application of this effec