深部中阶煤孔结构的压汞—液氮联合表征及孔隙分形特征  

Combined characterization of pore structure in deep medium⁃rank coal using mercury intrusion and liquid nitrogen adsorption methods and its pore fractal characteristics

作　　者：李奇 吴勇[1] 乔磊 LI Qi;WU Yong;QIAO Lei(College of Environment and Civil Engineering,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Wenzhou University of Technology,Wenzhou,Zhejiang 325006,China;Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province,Shaoxing,Zhejiang 312000,China)

机构地区：[1]成都理工大学环境与土木工程学院,成都610059 [2]温州理工学院,浙江温州325006 [3]浙江省岩石力学与地质灾害重点实验室,浙江绍兴312000

出　　处：《石油实验地质》2025年第1期130-142,共13页Petroleum Geology & Experiment

基　　金：浙江省岩石力学与地质灾害重点实验室开放基金项目(ZJRMG-2023-01)资助。

摘　　要：为研究深部中阶煤的孔隙结构特征与孔隙分形规律,利用压汞法和液氮吸附法对沈阳红阳三矿、开滦林西矿、淮南新集二矿和平顶山平煤六矿等典型深部开采矿区的主采煤层煤样进行了孔径、孔容、比表面积等参数测试,基于Menger海绵模型和FHH模型进行了孔隙分形规律的研究。结果表明:(1)基于压汞法的孔隙结构参数测试中平均孔径31.10~34.70 nm,总孔容0.0483~0.0594 mL/g,总比表面积5.5909~7.6528 m^(2)/g,得出典型深部开采矿区的主采煤层孔隙发育比较接近;孔容分布以大孔孔容占主导,微孔与过渡孔孔容比重相当,中孔的孔容分布相对较小,表明大孔孔隙连通性较好,中孔较为闭塞;比表面积分布以微孔为主,占比达70%以上,而中孔和大孔的比重甚微,可见微孔吸附能力最强,不利于深部煤层瓦斯治理;Menger海绵模型分形维数介于2.6~3之间,表明孔隙形状很不规则,孔隙较为复杂,整体上孔隙表面较为粗糙。(2)基于液氮吸附法测试的有效孔径范围为3~177 nm,总孔容与比表面积不同的矿区差异明显,孔容分布以过渡孔和中孔为主,微孔分布较低,大孔为0,表明利用液氮吸附法对于中孔、过渡孔有很好的表征,而难以表征大孔结构,且微孔的孔隙连通性较差;比表面积分布中主要为过渡孔、微孔和中孔,大孔为0,其中以过渡孔为主,且其吸附能力也较强;FHH模型分形维数介于2.0~2.7,结构较为简单规则。(3)讨论了深部中阶煤孔隙结构差异性,其中压汞法和液氮法的孔隙结构参数(比表面积、孔容)随埋深的增加均呈非线性的凹曲线变化;Menger海绵模型与FHH模型分形维数则随埋深的增加呈凸曲线的变化趋势。To study the pore structure and fractal characteristics of deep medium⁃rank coal,combined characteriza⁃tion using mercury intrusion and liquid nitrogen adsorption methods was conducted on coal samples from the main coal seams in typical deep mining areas,including Shenyang Hongyang Third Mine,Kailuan Linxi Mine,Huainan Xinji Second Mine,and Pingdingshan Pingmei Sixth Mine.Parameters such as pore size,pore volume,and specific surface area were obtained,and the pore fractal characteristics were studied based on the Menger sponge model and the FHH model.The results showed that:(1)Among the pore structure parameters tested with mercury intrusion method,the average pore size ranged from 31.10 to 34.70 nm,pore volume from 0.0483 to 0.0594 mL/g,and specific surface area from 5.5909 to 7.6528 m^(2)/g.The pore development in the main coal seams of typical deep mining areas was relatively similar.The pore volume distribution was dominated by macropores,with micropores and transition pores contributing roughly equally,and mesopores having a relatively small distribution.This indi⁃cated that macropores had better connectivity and mesopores were more closed.Micropores accounted for more than 70%of the total specific surface area,while the proportions of mesopores and macropores were minimal,indica⁃ting that micropores had the strongest adsorption capacity,which was negatively affected gas management in deep coal seams.The fractal dimensions based on the Menger sponge model ranged from 2.6 to 3.0,indicating irregular pore shapes,complex pore structures,and generally rough pore surfaces.(2)The effective pore size tested using liquid nitrogen adsorption method ranged from 3 to 177 nm with significant differences in total pore volume and specific surface area among the mining areas.Pore volume distribution was dominated by transition pores and meso⁃pores,with a lower distribution of micropores and no macropores.This indicated that liquid nitrogen adsorption was effective for characterizing mesopores and transition pores

关 键 词：深部中阶煤 压汞法 液氮吸附法 孔径结构 孔隙分形 

分 类 号：TE132.2[石油与天然气工程—油气勘探]