In-situ observation and modeling approach to evolution of pore-fracture structure in coal

作     者：Hongwei Zhou Zelin Liu Jiawei Zhao Bocen Chen Xiangnan Li Jiangcheng Zhong Hongwei Zhou;Zelin Liu;Jiawei Zhao;Bocen Chen;Xiangnan Li;Jiangcheng Zhong

作者机构：School of Energy and Mining EngineeringChina University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Coal Resources and Safe MiningChina University of Mining and Technology-BeijingBeijing 100083China School of Mechanics and Civil EngineeringChina University of Mining and Technology-BeijingBeijing 100083China 

出 版 物：《International Journal of Mining Science and Technology》 (矿业科学技术学报（英文版）)

年 卷 期：2023年第33卷第3期

页      面：265-274页

核心收录：

学科分类：081901[工学-采矿工程] 0819[工学-矿业工程] 08[工学] 0818[工学-地质资源与地质工程] 0702[理学-物理学] 

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.51827901,52121003,52142302,and 51904309) the 111 Project(No.B14006) the Yueqi Outstanding Scholar Program of CUMTB(No.2017A03). 

主　　题：Pore-fracture structure Fractional derivative Stress sensitivity Compressibility Nuclear magnetic resonance imaging 

摘      要：The characterisation of the pore-fracture structure(PFS)and its evolution in coal during mining are essential for preventing gas outbursts and improving gas extraction efficiency.In this study,the evolution of the PFS in coal samples under the condition of mining stress was directly captured in situ by combination of the mechanical testing system with high-precision visualisation nuclear magnetic resonance equipment.A fractional derivative model was established to describe the relationship between stress and porosity based on experimental results of the PFS under different stress states.The results showed that with an increase in the deviatoric stress,the adsorption pore content increases rapidly initially and then increases slowly or remains unchanged;the seepage pore and fracture(SPF)content decreases initially and then increases.The SPF compressibility coefficient decreases with an increase in the deviatoric stress.The fractional derivative model can accurately describe the stress sensitivity of the SPFs at the pre-peak stage,thus providing a new approach for accurately characterising the seepage characteristics of coal reservoirs.