基于X-ray CT与FIB-SEM的无烟煤孔裂隙发育特征  

Characteristics of pores and fractures in anthracite coal based on X-ray CT and FIB-SEM

作　　者：胡秋嘉 刘世奇[2,3] 毛崇昊 贾慧敏 闫玲[1] 王鹤 高德燚 HU Qiujia;LIU Shiqi;MAO Chonghao;JIA Huiming;YAN Ling;WANG He;GAO Deyi(PetroChina Shanxi CBM Branch,Changzhi 04600,China;Low Carbon Energy Instiute,China Universily of Mining and Technology,Xuzhou 221008,China;Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization,China University of Mining and Technology,Xuzhou 221008,China;School of Mineral Resource and Geoscience,China University of Mining and Technology,Xuzhou 221116,China;Key Laboralory of Coalbed Methane Resources and Resernoir Formation Process(Ministry of Education),China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国石油天然气股份有限公司,山西煤层气勘探开发分公司,山西长治046000 [2]中国矿业大学,低碳能源研究院,江苏徐州221008 [3]中国矿业大学,江苏省煤基温室气体减排与资源化利用重点实验室,江苏徐州221008 [4]中国矿业大学,资源与地球科学学院,江苏徐州221116 [5]中国矿业大学,煤层气资源与成藏过程教育部重点实验室,江苏徐州221116

出　　处：《煤矿安全》2021年第9期10-15,21,共7页Safety in Coal Mines

基　　金：国家自然科学基金资助项目(41972168);中国石油天然气股份有限公司重大科技专项资助项目(2017E-1405)。

摘　　要：以沁水盆地南部无烟煤为研究对象,基于X-ray CT和FIB-SEM扫描成像试验,构建了无烟煤孔裂隙网络结构模型并提取了关键特征参数,进而对无烟煤孔裂隙发育特征与连通关系开展了定量研究。结果表明:沁水盆地南部无烟煤以孔径小于50 nm的中孔为主,大孔数量较低,显微裂隙和割理对孔隙体积具有较高的贡献;孔隙截面以不规则形状为主,毛管阻力较大;孔隙具有较好的连通性,连通路径较丰富,有利于气体运移和产出;随孔裂隙发育尺度的减小,孔裂隙连通性和渗透率随之降低;对连通性起主要作用的是中孔、显微裂隙和割理;显微裂隙和割理提高了无烟煤微米尺度、毫米尺度孔裂隙的连通性和渗透性,无烟煤纳米尺度以中孔连通为主,限制了无烟煤整体连通性。Taking the anthracite coal in the southerm of Qinshui Basin as the research object, the pore-fracture network models of anthracite coal were established and the key parameters of pore-fracture network were extracted based on the X-ray CT(computed tomography) and focused ion beam scanning electron microscopy(FIB-SEM) imaging experiments. Then, the characteristics of pores and fractures in anthracite coal and their connection relationships were quantitative studied. The results show that the pores of anthracite coal in the southern Qinshui Basin are mainly mesopores with pore size less than 50 nm.Macropore content in anthracite coal is small, and microscopic fractures and cleats make a great contribution to pore volume in anthracite coal. The cross-section is predominantly irregular in shape, which means that the capillary resistance is large. The connectivity of the pores is well with multiple connected paths, which is beneficial to gas migration and output. With the decrease of the scale of pores and fractures, the connectivity and permeability of pore and fracture decrease. Mesopores, microscopic fractures, and cleats play an important role in the connectivity of anthracite coal. The connectivity and permeability of micrometer and millimeter scale pores and fractures in anthracite coal were improved by microscopic fractures and cleats, while the connectivity of nanoscale pores in anthracite coal was dominated by mesopores, which limited the connectivity of anthracite coal.

关 键 词：煤层割理 显微裂隙 连通性 孔裂隙网络模型 沁水盆地南部 

分 类 号：TD713[矿业工程—矿井通风与安全]