三轴条件下递增瓦斯压力和煤样孔隙结构对瓦斯解吸-渗流影响研究  

Effects of increasing gas pressure and pore structure of coal samples to gas desorption-seepage laws under triaxial conditions

作　　者：蔡雨初 李树刚 孔祥国[1,3,4] 杨送瑞 季鹏飞 和递 CAI Yuchu;LI Shugang;KONG Xiangguo;YANG Songrui;JI Pengfei;HE Di(College of Safety Science and Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;College of Chemistry and Chemical Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Key Laboratory of Western Mine Exploitation and Hazard Prevention,Ministry of Education,Xi’an University of Science and Technology,Xi’an 710054,China;Western Engineering Research Centre of Mine Gas Intelligent Drainage for Coal Industry,Xi’an 710054,China)

机构地区：[1]西安科技大学安全科学与工程学院,陕西西安710054 [2]西安科技大学化学与化工学院,陕西西安710054 [3]西安科技大学西部矿井开采及灾害防治教育部重点实验室,陕西西安710054 [4]煤炭行业西部矿井瓦斯智能抽采工程研究中心,陕西西安710054

出　　处：《西安科技大学学报》2025年第2期305-316,共12页Journal of Xi’an University of Science and Technology

基　　金：国家自然科学基金项目(52404243,52474251,52374227)。

摘　　要：煤体孔隙结构是影响矿井瓦斯抽采的根源因素,而瓦斯抽采涉及瓦斯解吸-渗流等运移阶段,因此,研究煤体孔隙结构对三轴原位赋存条件下瓦斯解吸-渗流规律的影响十分必要。通过煤层气流固耦合测试平台,对5种代表性煤样进行解吸-渗流试验,研究了递增瓦斯压力下不同煤样解吸量和渗流速率随时间的变化规律,分析了解吸量、渗流速率与递增瓦斯压力相关性。结果表明:在轴压4.0 MPa和围压3.5 MPa条件下,5种典型煤样解吸量、渗流速率随时间变化过程均可分为快速增长、缓慢增长和稳定维持阶段;在瓦斯解吸阶段,赵固二矿(ZG)煤样解吸时间远大于其他煤样,但其解吸量远小于其他煤样,主要是其微小孔与中大孔之间的孔喉结构较多,较小孔喉及封闭孔喉占比较大;瓦斯压力从1.5 MPa递增至2.7 MPa,大柳塔(DLT)煤样解吸率增加最大为54%,而ZG煤样解吸率在40%上下波动(幅度小于4%),瓦斯压力对ZG煤样孔隙结构破坏远低于其他煤样;在瓦斯渗流阶段,煤样瓦斯渗流速率随瓦斯压力递增表现为显著的线性正相关,主要是高瓦斯压力对煤样孔隙和裂隙的扩容效应更强,瓦斯渗流速率将决定现场瓦斯抽采效率,而瓦斯解吸量大小将影响瓦斯抽采能力,二者将共同决定瓦斯抽采效果。基于煤样孔隙结构和递增瓦斯压力条件提出三轴煤样瓦斯解吸-渗流机理,对现场瓦斯抽采及瓦斯灾害防治具有一定借鉴意义。The pore structure of coal is the root factor affecting mine gas extraction,and gas extraction involves the migration stages such as gas desorption and seepage,so it is necessary to study the influence of coal pore structure on gas desorption-seepage law under the condition of triaxial in-situ occurrence.The desorption-seepage experiments of five representative coal samples were carried out through the coalbed methane fluid-solid interaction test platform,the variation of desorption and seepage rate of different coal samples with time under increasing gas pressure was studied,and the correlation between absorption and seepage rate and increasing gas pressure was analyzed.The results show that under the conditions of axial compression of 4.0 MPa and confining pressure of 3.5 MPa,the desorption capacity and seepage rate of five typical coal samples can be divided into such stages as rapid growth,slow growth and stable maintenance.In the gas desorption stage,the desorption time of coal samples from Zhaogu No.2 Mine(ZG)is much greater than that of other coal samples,but its desorption capacity was much smaller than that of other coal samples.Because there are more pore throat structures between micropores and medium and large pores,and the proportions of small pore throats and closed pore throats is larger.The gas pressure increases from 1.5 MPa to 2.7 MPa,and the desorption rate of DLT coal samples increases by 54%at the maximum,while the desorption rate of ZG coal samples fluctuates around 40%(less than 4%),indicating that the damage of gas pressure to the pore structure of ZG coal samples is much lower than that of other coal samples.In the gas seepage stage,the gas seepage rate of coal samples is significantly linear and positively correlated with the increase of gas pressure,mainly because the expansion effect of high gas pressure on the pores and fissures of coal samples is stronger.The gas seepage rate determines the on-site gas extraction efficiency,and the gas desorption capacity affects the gas extraction c

关 键 词：解吸-渗流 瓦斯压力 三轴受载条件 孔隙特征 煤样 

分 类 号：TD712[矿业工程—矿井通风与安全]