超临界CO_(2)作用下高阶煤微观结构及力学特性-声发射特征研究  

Experimental study of microstructure and mechanical properties-acoustic emission characterization of high-rank coal under supercritical CO_(2)action

作　　者：刘佳佳[1,2,3,4] 许艳之 聂子硕 张云龙 高建良 王丹[1,3,4] LIU Jiajia;XU Yanzhi;NIE Zishuo;ZHANG Yunlong;GAO Jianliang;WANG Dan(School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan 232001,China;Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization,Henan Polytechnic University,Jiaozuo 454003,China;Henan Provincial Key Laboratory of Gas Geology and Gas Control-Provincial and Ministry of State Key Laboratory Breeding Base,Henan Polytechnic University,Jiaozuo 454003,China)

机构地区：[1]河南理工大学安全科学与工程学院,河南焦作454003 [2]安徽理工大学深部煤矿采动响应与灾害防控国家重点实验室,安徽淮南232001 [3]河南理工大学煤炭安全生产与清洁高效利用省部共建协同创新中心,河南焦作454003 [4]河南理工大学河南省瓦斯地质与瓦斯治理重点实验室—省部共建国家重点实验室培育基地,河南焦作454003

出　　处：《煤炭科学技术》2024年第10期127-135,共9页Coal Science and Technology

基　　金：国家自然科学基金资助项目(52074106);河南省优秀青年基金资助项目(232300421061);中国博士后科学基金资助项目(2024M750803)。

摘　　要：超临界CO_(2)压裂技术作为极具发展潜力的压裂煤体增透瓦斯技术,明晰其对煤体的影响机制,有助于推动该技术的机理研究和实践工程应用。为准确表征超临界CO_(2)作用下高阶煤的孔裂隙结构及力学特性变化,以焦煤集团中马村矿的高阶煤为试验对象,通过自主搭建的超临界CO_(2)浸泡试验系统,结合全自动物理吸附仪(BET)以及全自动压汞仪(MIP),对超临界CO_(2)处理前后高阶煤的孔裂隙结构变化进行分析,并利用单轴压缩和声发射试验系统对超临界CO_(2)处理前后高阶煤的单轴压缩力学特性和声发射特征进行测定。结果表明:超临界CO_(2)对高阶煤具有良好的扩孔增渗作用。超临界CO_(2)处理后高阶煤的微小孔孔容占比降低,中大孔孔容占比增大,且高阶煤的总孔容增大;超临界CO_(2)对高阶煤的力学特性具有明显的劣化作用。超临界CO_(2)处理后高阶煤单轴抗压强度和弹性模量均显著下降,降幅分别为70.06%和55.56%,且超临界CO_(2)处理后高阶煤的内部声发射信号活跃度明显下降,高阶煤单轴抗压时间、累计振铃计数以及累计能量分别降低了98.68 s、95.14×10^(3)个、200.30 V·ms,降幅分别为46.65%、37.65%、50.03%,高阶煤累计振铃计数以及累计能量平静期占比均显著增加,缓增期占比均降低,激增期前者占比降低,后者占比小幅度增加。研究成果将有助于推动超临界CO_(2)压裂技术的机理研究,对深部高阶煤的煤层气开采和CO_(2)地下封存具有一定指导意义。The supercritical CO_(2)fracturing technology has significant potential for developing coal fracture and increasing gas permeability.Understanding its influence mechanism on coal is crucial for advancing research and practical engineering applications of this technology.In order to accurately characterize the changes of pore-fracture structures and mechanical properties of the high-rank coal under the action of supercritical CO_(2),taking high-rank coal from Zhongmacun Mine of Coking Coal Group as the experimental object,the changes of pore and fracture structure of the high-rank coal before and after supercritical CO_(2)treatment were analyzed by Brunauer-Emmet-Teller(BET)and Mercury intrusion porosimetry(MIP),and the mechanical and acoustic emission characteristics of the high-rank coal before and after supercritical CO_(2)treatment were tested by combining with uniaxial compression and acoustic emission experimental system.The results show that supercritical CO_(2)had a good effect on pore expansion and permeability enhancement of the high-rank coal.After supercritical CO_(2)treatment,the percentage of micro-small pore volume of the high-rank coal decreased,the percentage of medium and large pore volume increased,and the total pore volume of the high-rank coal increased after supercritical CO_(2)treatment.Supercritical CO_(2)had an obvious deteriorating effect on the mechanical properties of the high-rank coal.The uniaxial compressive strength and modulus of elasticity of the high-rank coal after supercritical CO_(2)treatment were significantly decreased by 70.06%and 55.56%,respectively.The acoustic emission signal activity of the high-rank coal after supercritical CO_(2)treatment decreased significantly,and the uniaxial compressive time,cumulative ring counts and cumulative energy of the high-rank coal were reduced by 98.68 s,95.14×10^(3),and 200.30 V·ms,with the decreases of 46.65%,37.65%,and 50.03%,respectively.The proportion of accumulated ringing count and accumulated energy in the quiet period of high

关 键 词：超临界CO_(2) 高阶煤 孔隙结构 力学特性 声发射特性 扩孔增渗 

分 类 号：TD712[矿业工程—矿井通风与安全]