The mechanism of inward and outward expansion of multiscale dynamic permeability of coalbed methane at different temperatures

作     者：Zhiqiang Li Xiaoqiang Hao Yanwei Liu Lin Li Zhiqiang Li;Xiaoqiang Hao;Yanwei Liu;Lin Li

作者机构：MOE Engineering Center of Mine Disaster Prevention and RescueHenan Polytechnic UniversityJiaozuoChina Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency UtilizationHenan Polytechnic UniversityJiaozuoChina Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region(Henan Province)Henan Polytechnic UniversityJiaozuoChina Henan Provincial Key Lab of Gas Geology and Control‐Cultivation Base of Provincial and Ministry Joint State KeyHenan Polytechnic UniversityJiaozuoChina 

出 版 物：《Deep Underground Science and Engineering》 (深地科学（英文）)

年 卷 期：2023年第2卷第1期

页      面：88-101页

核心收录：

学科分类：07[理学] 0708[理学-地球物理学] 

基　　金：Doctoral Foundation of Henan Polytechnic University,Grant/Award Number:B2021-7 Key Science and Technology Project of Henan Province,Grant/Award Number:222102320017 State Key Laboratory Cultivation Base for Gas Geology and Gas Control(Henan Polytechnic University),Grant/Award Number:WS2021A06 National Natural Science Foundation of China,Grant/Award Number:52174173 Key Scientific Research Projects of Colleges and Universities in Henan Province,Grant/Award Number:22B620002 Fundamental Research Funds for the Universities of Henan Province,Grant/Award Number:NSFRF180305 

主　　题：diffusion dynamic gas permeability seepage temperature 

摘      要：The multiscale micro-nano pores in coal can result in the ultra-low permeability of coal,which restricts the efficiency of gas *** is difficult for the conventional seepage-enhancement measures to affect the nanoscale pores within the coal *** stimulation can reach deep into the micro-nano pores within coal matrix to improve the ***,it is important to study the diffusivity and permeability of the multiscale micro-nano pores at different *** this study,the experiments of diffusion-seepage measured by the methods of GRI(Gas Research Institution)and steady-state were conducted using a cylindrical coal at different temperatures and *** experimental results show that the apparent diffusion coefficient of cylindrical coal is not constant but variable dynamically;and the classical diffusion model fails to describe the full-time process of gas flow *** this basis,a model of multiscale dynamic apparent diffusion-seepage that can accurately describe the full-time flow process was *** is observed,the apparent permeability attenuates dynamically with time without stress loading,and the initial apparent permeability and the attenuation coefficient increase monotonically with the rise of *** the stress constraint,the steady-state permeability increases after a decrease as the temperature rises,displaying a“U-shaped*** stress constraint,the increasing temperature causes the exterior multiscale pores to expand outward by different degrees so as to increase permeability,while the interior micro-nano pores show three inward and outward expansion *** stress constraint,at low temperature and high effective stress,the increasing temperature causes pores to expand inward and the permeability decreases *** temperature continues to increase,coal expands outward because the effective stress is counteracted by the thermal stress,leading to an increase in permea