摘要
煤层瓦斯流动规律与煤的孔隙结构密切相关。为揭示贵州地区突出煤层微观孔隙结构特征及对其瓦斯流动特性的影响,以贵州地区6个典型矿井突出煤层为研究对象,采用高压容量法测试了6个煤样的吸附能力。同时,根据高压压汞试验,利用分形方法获得煤样分形维数,并分析样品的微观孔隙结构分形特征及其与煤质参数的关系。在此基础上,探讨多尺度孔隙中瓦斯流动规律,分析吸附作用对瓦斯流动特性的影响。结果表明,贵州突出煤层以微孔为主,微孔为比表面积和孔隙体积的主要贡献者。同一煤样微孔分形维数D1、小孔分形维数D2和中孔分形维数D3依次增大,且分形特征明显。D1和综合分形维数Dk与水分呈负相关,挥发分与D2、D3呈负相关,灰分和D3呈负相关。突出煤层中瓦斯扩散模式主要为Knudsen型和过渡型。在Knudsen扩散区和过渡扩散区,渗透率受温度和压力影响较小;Fick扩散区,在相同努森数Kn和温度条件下,渗透率随压力增大而减小,随温度增高而降低;压力越高,孔径越小,渗透率受吸附作用影响越大。
The gas flow law of coal seam is closely related to the pore structure of coal.In order to reveal the micropore structure characteristics of outburst coal seams in Guizhou and its effect on gas flow,six outburst coal seams in typical mines in Guizhou Area were taken as the research objects,and the adsorption capacity of six coal samples was tested by the high pressure capacity method.At the same time,according to the high-pressure mercury test,the fractal dimension of the coal sample was obtained by the fractal method,and the fractal characteristics of the micropore structure of the coal and its relationship with the coal material composition were analyzed.On this basis,the law of gas flow in multi-scale pores was discussed,and the effect of adsorption on gas flow was analyzed.The results show that Guizhou outburst coal seams are dominated by micropores,which are the main contributors to the specific surface area and pore volume.The micropore fractal dimension D1,small pore fractal dimension D2 and mesopore fractal dimension D3 of the same coal sample increase sequentially,and the fractal characteristics are obvious.D1 and the integrated fractal dimension Dkare negatively correlated with moisture,the volatile matter is negatively correlated with D2 and D3,and the ash yield is negatively correlated with D3.The gas diffusion mode in outburst coal is mainly Knudsen type and transition type.In the Knudsen diffusion zone and transition diffusion zone,the permeability is less affected by temperature and pressure;in the Fick diffusion zone,under the same Knudsen number(Kn)and temperature,the permeability decreases with increasing pressure and decreases with increasing temperature.The higher the pressure,the smaller the pore size,and the more the permeability is affected by adsorption.
作者
李希建
薛海腾
陈刘瑜
沈仲辉
徐明智
许石青
LI Xijian;XUE Haiteng;CHEN Liuyu;SHEN Zhonghui;XU Mingzhi;XU Shiqing(Mining College,Guizhou University,Guiyang 550025,China;Engineering Center for Safe Mining Technology Under Complex Geologic Condition,Guiyang 550025,China;Institute of Gas Disaster Prevention and Coalbed Methane Development of Guizhou University,Guiyang 550025,China;State Key Laboratory for the Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044)
出处
《煤炭科学技术》
CAS
CSCD
北大核心
2020年第10期67-74,共8页
Coal Science and Technology
基金
国家自然科学基金资助项目(51874107)
贵州省科技计划资助项目(黔科合平台人才[2018]5781号)。
关键词
突出煤层
瓦斯吸附
孔隙结构
煤层渗透率
煤层分形维数
outburst coal seam
gas adsorption
pore structure
coal seam permeability
coal seam fractal dimension
作者简介
李希建(1967-),男,土家族,湖南张家界人,教授,博士生导师,博士。E-mail:575914635@qq.com;通讯作者:薛海腾(1994-),男,山西大同人,硕士研究生。E-mail:1014132071@qq.com。
