基于压汞、氮气吸附与FE-SEM的无烟煤微纳米孔特征  

Characteristics of macro-nanopores in anthracite coal based on mercury injection,nitrogen adsorption and FE-SEM

作　　者：赵迪斐[1,2] 郭英海[1,2] 毛潇潇[1] 卢晨刚 李咪[1] 钱福常 

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]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221008

出　　处：《煤炭学报》2017年第6期1517-1526,共10页Journal of China Coal Society

基　　金：国家重点基础研究发展计划(973)资助项目(2012CB214702);山西省煤基重点科技攻关资助项目(MQ201402);煤层气资源与成藏过程教育部重点实验室(中国矿业大学)开放基金资助项目(2015-007)

摘　　要：煤微纳米孔隙结构特征是揭示煤层气体赋存富集机理与扩散运移规律的基础。以阳泉矿区新景矿样品为例,利用氩离子抛光-场发射扫描电镜对纳米级孔隙形貌直观观测,结合低温氮吸附实验、高压压汞实验对微孔隙结构进行定量表征,以研究无烟煤微纳米级孔隙的发育特征。结果表明:煤储层纳米孔广泛发育,形貌特征复杂,类型包括植物细胞结构残余孔、镜质体基质气孔、有机显微组分间孔、黏土矿物孔隙、石英粒内孔、组分间孔、微裂隙等,与微米级孔隙共同构成完整的煤孔隙系统;煤样孔隙主体处于纳米量级,平均孔径约为39.31 nm,80%以上储集空间分布于100 nm以下,集中在10~40 nm;纳米孔分形维数介于2.72~2.90,显示较强的非均质性。储集空间的定量表征显示储层纳米级孔隙极为发育,炭质纳米孔是纳米孔中绝对优势的发育类型,微米级孔隙有一定发育程度,微裂隙发育较差。这样的孔隙结构特征是造成无烟煤吸附能力强而渗透能力较差的重要原因。The structure characteristics of coal micro/nano pore are the foundation for revealing the enrichment mecha- nism and the rule of diffusion and migration of gas in coal. Characteristics of anthracite samples from Xinjing coal mine in Yangquan were fully studied based on various experimental techniques including argon ion polishing-field emission scanning electron microscopy（FE-SEM） ,low temperature nitrogen adsorption and high pressure mercury injection in this paper. The results show that pores in nanoscale with the complex morphology of tested samples are widely devel- oped. As determined through the direct observation with FE-SEM, phyteral cell residual pore, vitrinite matrix pore, junction formed by ultramicroscopic maeeral, clay mineral pore, quartz intragranular pore, pore between components and micro-fractures were identified, which then constituted the coal interconnected pore system. The main reservoir space is in nanometer scale with an average pore diameter of 39.31 nm, more than 80% of the reservoir space is under 100 nm and concentrated in 10-40 nm range. The fractal dimension of nanopores is between 2.72-2.90, indicatingdistinct heterogeneity characteristics. The quantitative characterization showed that the nanopores developed well and the carbonaceous nanopore take an absolute advantage among all kinds of pore types, the macropores and mesopores have a certain degree while the microfissure is not, which brings about the high adsorption ability and poor penetration ability of coal reservoir.

关 键 词：无烟煤 纳米孔 孔隙类型 孔隙特征 孔径分布 

分 类 号：P618.11[天文地球—矿床学]