Characteristics of fractures in different macro-coal components in high-rank coal based on CT images

被引：0
作者：
Qu J. [1 ,2 ]
Shen J. [1 ,2 ]
Han L. [1 ,2 ]
Ji C. [3 ]
Cheng H. [1 ,2 ]
机构：
[1] Key Laboratory of Coalbed Methane Resource & Reservoir Formation Process, Ministry of Education, China University of Mining and Technology, Jiangsu, Xuzhou
[2] School of Resources and Geosciences, China University of Mining and Technology, Jiangsu, Xuzhou
[3] State Key Laboratory of Coal and CBM Co-mining, Shanxi, Jincheng
来源：
Natural Gas Industry | 2022年 / 42卷 / 06期
关键词：
Connectivity; Contrast agent; CT technology; Fracture characterization; Fracture content; High-rank coal; Macro-coal component; Porosity; Qinshui Basin;
D O I：
10.3787/j.issn.1000-0976.2022.06.007
中图分类号：
学科分类号：
摘要：
Development of fractures in coals has an important impact on the desorption diffusion seepage and production characteristic of coalbed methane (CBM), so its fine characterization is of great significance to CBM exploration and development. In this paper, CT scanning of coal samples before and after saturated contrast agent solution is carried out by taking the No.3 coal seam of Shanxi Formation of Lower Permian in Herui Mining Area of the Qinshui Basin as the research object. Based on CT scanning images, macro-coal components are identified and coal rocks are classified. In addition, the differential development rules of fractures are characterized by using different parameters. And the following research results are obtained. First, CT scanning responses obviously to macro-coal components and can identify macro-coal components according to gray scale difference, so as to determine the macrolithotype of coals. Second, compared with conventional dry samples, CT fracture cutting after the application of contrast agent solution can improve the fracture identification accuracy greatly and its fracture porosity is higher, which is close to gas logging porosity. Third, the combination patterns of coal components are different in different macrolithotypes of coals. From semi-dull coals to bright coals, the dull + fusain transforms from a wider band to a thin band or line, and the content of lenticular fusains increases. In conclusion, fracture content is in a stronger correlation with the macrolithotype of coals, which is the highest in bright coals and the lowest in semi-dull coals. Fracture spacing is influenced by the combination pattern of macro-coal components, which is the largest in bright coals and the smallest in semi-dull coals. Fracture connectivity is not only influenced by the content of coal components, but also by the combination pattern of coal components, which is the best in semi-bright coals and the worst in semi-dull coals. What's more, the fractures in vitrain + clarain are superior to those in durian + fusain in terms of aperture, spacing and connectivity. © 2022 Natural Gas Industry Journal Agency. All rights reserved.
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页码：76 / 86
页数：10
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