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沁水盆地东南部高阶煤孔隙分形特征及意义
供稿: 高迪;刘建国 时间: 2018-11-21 次数:

作者:高迪;刘建国

作者单位:煤与煤层气共采国家重点实验室河南理工大学资源环境学院;中原经济区煤层(页岩)气河南省协同创新中心

摘要:为研究有利于煤层气勘探开发的煤储层孔隙结构特征,以沁水盆地东南部寺河矿和赵庄矿的晚古生代高阶煤为研究对象,基于低温氮吸附数据,运用孔隙分形研究方法,揭示高阶煤中综合分形维数与孔径分布、镜质组反射率、兰氏体积与兰氏压力之间的关系。研究表明,沁水盆地南部高阶煤在不同孔径段内的孔隙具有明显的分形特征,煤样综合分形维数分布在2.47~2.97;煤样的综合分形维数与煤镜质组反射率具有正相关性,即煤样孔隙的粗糙度随着镜质组反射率的增高而变得更加粗糙;综合分形维数随着比表面积、总孔容、微孔及过渡孔孔容所占比例增加而增大,而随着中孔孔容所占比例的增加而减小。综合分形维数可以反映高阶煤的煤层气开发状况,即高阶煤中煤的综合分形维数越高,越有利于煤层气的开发。

基金:国家自然科学基金资助项目(41402094);山西省煤基金重点科学攻关项目(MQ2014-03);河南理工大学博士基金资助项目(B2011-0B);

关键词:沁水盆地;低温氮吸附;孔隙特征;分形维数;兰氏体积;

DOI:10.16186/j.cnki.1673-9787.2017.02.002

分类号:P618.11

Abstract:In order to investigate coal reservoir pore structure characteristics which is in favor of coalbed methane exploration and development, the Late Paleozoic high rank coal of Sihe and Zhaozhuang mine in Southern Qinshui Basin is used as research object.The relationship between the total fractal dimension and the fractal characteristics of pore, vitrinite reflectance, Langmuir volume and Langmuir pressure was studied based on cryogenic nitrogen adsorption results.The results show that the pore distribution determined by nitrogen adsorption has obvious fractal characteristic in different aperture.Fractal dimension of pore test by low temperature nitrogen adsorption experiment is 2.47 ~ 2.97.There is a positive correlation between fractal dimension and vitrinite reflectance, pore roughness increases with the increase of vitrinite reflectivity.The fractal dimension increases with the increase of the specific surface area, pore volume, micropore and transition pore proportion.Meanwhile, fractal dimension decreases with the increase of the mesopore.The total fractal dimension play an important role in the development of coalbed methane of high rank coal, that is to say the higher the total fractal dimension of high rank coal, the more beneficial to coalbed methane development.

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