摘要
研究构造煤结构有助于深入理解煤与瓦斯突出易发区储层瓦斯赋存及运移规律,而从微观形态学结构角度精细定量化表征的研究相对较少。本文通过原子力显微镜、压汞法和物理吸附法开展构造煤和原生煤的三维表观形貌、孔隙发育程度、孔径分布、形态特征参数及连通特性等,旨在从本质上揭示两者微观多尺度结构差异性及对瓦斯运移的影响。结果表明:构造作用促使极限吸附量增大,煤结构整体强度降低,且气体瞬间解吸能力增强;构造煤结构表面形态特性由规则纳米孔向凹凸不平条带状微裂隙转变,脆性构造变形也导致孔隙整体呈现高粗糙度且不圆润形状;不论是原生煤还是构造煤,微孔对整体孔容和比表面积均具有重要贡献,但其对构造应力敏感程度低于介孔和大孔,其中构造煤的介孔孔容和比表面积相比原生煤增幅分别约4倍和10倍,大孔也分别提升了0.0088 cc/g和1.459 m^(2)/g;通过压汞法进退汞曲线及滞后环可知,构造煤中有效孔比例从76.95%降低至74.21%,导致气体自由运移空间降低,主要归因于由交联孔和半开放孔构成的限制型孔喉配置结构的大量存在;构造作用促使孔喉比和曲折度分别降低了约10%和0.5%,运移路径缩短且孔隙形态结构更加简单化;通过液氮吸附脱附曲线及滞后环可知,构造作用可能从本质上改变了孔隙形态结构特征,促使产生更多限制型孔隙配置关系,抑制了气体有效运移属性。
A study of tectonic coal structure contributes to understand the mechanism of gas occurrence and migration in the outburst prone area.However,few researches focused on fine quantitative characterization from the perspective of microscopic morphology.In this work,Atomic Force Microscopy(AFM),mercury intrusion porosimetry(MIP)and physical adsorption method were adopted to explore the apparent morphology,pore development,pore size distribution,morphological parameters and connectivity of original and tectonic coals.The results show that tectonism may increase ultimate adsorption capacity,reduce the structure strength,and enhance instantaneous desorption capacity.Surface morphological feature of tectonic coal changed from regular nanopores to irregularity microfractures,and brittle tectonic deformation led to high roughness and unrounded pore shape.Whether it is original coal or tectonic coal,micropores significantly contribute to Total Pore Volume(TPV)and Specific Surface Area(SSA).However,micropores are slightly sensitive to tectonic stress,lower than that of mesopores and macropores.Compared with original coal,TPV and SSA of mesopore in tectonic coal increased by about 4 and 10 times,respectively;while the macropores also increased by 0.0088 cc/g and 1.459 m^(2)/g,respectively.From MIP curves and hysteresis loop,the proportion of effective pores in tectonic coal decreased from 76.95%to 74.21%,resulting in the space reduction of free gas migration.Tectonism could reduce pore-throat ratio and pore tortuosity by about 10%and 0.5%,respectively,shortening the migration path and simplifying the pore morphology.From N 2(77 K)adsorption/desorption isotherm and hysteresis loop,Tectonism may essentially alter pore morphology and structural property,promoting more constricted pore configuration,and inhibiting the effective gas migration properties.
作者
王士路
张开仲
杜联营
韩希伟
王明
WANG Shilu;ZHANG Kaizhong;DU Lianying;HAN Xiwei;WANG Ming(Engineering Laboratory of Deep Mine Rockburst Disaster Assessment,Shandong Province,Qingdao 266404,China;The First Prospecting Team of Shandong Bureau of Coal Geology,Qingdao 266404,China;IoT Perception Mine Research Center,China University of Mining and Technology,Xuzhou 221008,China;Shandong Province Research Institute of Coal Geology Planning and Exploration,Jinan 250104,China;State Key Laboratory Cultivation Base for Gas Geology and Gas Control,Henan Polytechnic University,Jiaozuo 454003,China)
出处
《西安科技大学学报》
CAS
北大核心
2021年第5期862-871,共10页
Journal of Xi’an University of Science and Technology
基金
山东省深部冲击地压灾害评估工程实验室开放项目(鲁煤研开(2020)008号)
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开放基金项目(WS2020B02)。
关键词
构造煤
孔隙结构
表观形貌
形态学
多尺度表征
tectonic coal
pore structure
surface topography
morphology
multiscale characterization
