Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths
作者机构：School of Mechanics and Civil Engineering China University of Mining and Technology Xuzhou 221116 China State Key Laboratory of Mining Disaster Prevention and Control Ministry of Education Shandong University of Science and Technology Qingdao 266590 China School of Safety Engineering China University of Mining and Technology Xuzhou 221116 China State Key Laboratory of Coal Mine Disaster Prevention and Control China University of Mining and Technology Xuzhou 221116 China Key Laboratory of Theory and Technology on Coal and Rock Dynamic Disaster Prevention and Control National Mine Safety Administration China University of Mining and Technology Xuzhou 221116 China
出 版 物：《International Journal of Mining Science and Technology》 (Int. J. Min. Sci. Technol.)
年 卷 期：2024年第34卷第11期
页 面：1495-1508页
核心收录：
学科分类：0820[工学-石油与天然气工程] 0709[理学-地质学] 0819[工学-矿业工程] 081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程]
基 金：This study was financially supported by the National Natural Science Foundation of China (Nos. 52304265 52174216 and 52274145 ) the Natural Science Foundation of Jiangsu Province (No. BK20221121 ) the State Key Laboratory of Mining Disaster Prevention and Control (Shandong University of Science and Technology) and Ministry of Education (No. JMDPC202301 )
摘 要：Both bulk stress (σii) and stress path (SP) significantly affect the transportation characteristics of deep gas during reservoir pressure depletion. Therefore, the experimental study of horizontal stress unloading on seepage behavior of gas-bearing coal under constant σii-constraints is performed. The results show that coal permeability is affected by horizontal stress anisotropy (σH≠σh), and the contribution of minor horizontal stress to permeability is related to the differential response of horizontal strain. The slippage phenomenon is prominent in deep high-stress regime, especially in low reservoir pressure. σii and SP jointly determine the manifestation of slippage effect and the strength of stress sensitivity (γ) of permeability. Deep reservoir implies an incremental percentage of slip-based permeability, and SP weakens the slippage effect by changing the elastic–plastic state of coal. However, γ is negatively correlated with slippage effect. From the Walsh model, narrow (low aspect-ratio) fractures within the coal under unloading SP became the main channel for gas seepage, and bring the effective stress coefficient of permeability (χ) less than 1 for both low-stress elastic and high-stress damaged coal. With the raise of the effective stress, the effect of pore-lined clay particles on permeability was enhanced, inducing an increase in χ for high-stress elastic coal. © 2024
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