Quantitative Characterization of Pore–Fracture Structures in Deep Coal Reservoirs Based on the QSGS Method

Dongxiang Huang

doi:10.63313/JCSFT.9071

Authors

Dongxiang Huang School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan 454000, China Author

DOI:

https://doi.org/10.63313/JCSFT.9071

Keywords:

Multiscale digital core, Coal pore structure, Micro-CT, QSGS method

Abstract

This study aims to improve the characterization of multiscale pore structures in coal by constructing a more representative digital core model. Mercury intrusion porosimetry, micro-CT scanning, Avizo-based image processing, and the quartet structure generation set (QSGS) method were integrated to reconstruct the pore–fracture networks of four coal samples. Mercury intrusion data were used to determine porosity and pore-size distribution, while micro-CT images were applied to establish three-dimensional pore network models. To overcome the resolution limitation of CT imaging, the QSGS method was further used to supplement unresolved micropores. The results indicate that the proposed multiscale digital core can more accurately represent the pore structure of coal samples. Connectivity analysis based on Euler number, tortuosity, and coordination number shows clear differences in pore connectivity among the samples. This approach provides an effective method for pore structure characterization and offers a basis for permeability prediction and coalbed methane development.

References

[1] Guo Xuejing, He Shunli, Chen Sheng, et al. Microscopic structure and distribution characteristics of shale pores based on nano-CT and digital core[J]. Coal Geology of China, 2016, 28(02): 28–34.

[2] Xu Wenshuo, Liang Lixi, Gou Jianru, et al. Characterization of pore structure in glutenite based on micro-CT scanning[J]. Science Technology and Engineering, 2025, 25(03): 999–1007.

[3] Zhang Wenzheng, Qiu Lei. Characterization and analysis of coal pore structure based on CT three-dimensional reconstruction[J]. Coal Technology, 2018, 37(12): 327–329. DOI: 10.13301/j.cnki.ct.2018.12.116.

[4] Wang Gang, Shen Junnan, Chu Xiangyu, et al. Comprehensive characterization and analysis of pore–fracture structure in high-rank coal based on CT three-dimensional reconstruction[J]. Journal of China Coal Society, 2017, 42(08): 2074–2080. DOI: 10.13225/j.cnki.jccs.2016.1764.

[5] Shi Yu, Ma Yuhua, Li Shugang, et al. Three-dimensional reconstruction of coal samples and gas apparent permeability based on CT scanning technology[J]. Mining Safety & Environmental Protection, 2024, 51(01): 27–35. DOI: 10.19835/j.issn.1008-4495.20230742.

[6] Wang Zhao, Du Junjie, Liu Junxiong. Porous media model based on the quartet structure generation set method[J]. Energy Research and Management, 2023, 15(02): 88–94. DOI: 10.16056/j.2096-7705.2023.02.013.

[7] Tian Zhongwei, Chen Lin. Construction of pore–fracture structures and analysis of their sizes based on the quartet structure generation set method[J]. Inner Mongolia Coal Economy, 2017, (11): 110–112. DOI: 10.13487/j.cnki.imce.010100.

[8] Song Xiong. Study on acoustic characteristics of coal rock based on digital coal samples[D]. China University of Mining and Technology, 2019.

[9] Zhang Wenzheng, Wang Jingxi. Comprehensive characterization of microscopic pore structures of different coal types based on micro-CT[J]. Coal Science and Technology, 2021, 49(S2): 85–92.