Fractal Characterization of Pressure-Relief Gas Permeability Evolution in a Mining Fracture Network

Peiyun Xu, Shugang Li, Haifei Lin, Yang Ding, Haiqing Shuang, Sibo Liu and Yu Tian
Additional contact information
Peiyun Xu: School of Safety Science and Engineering, Xi’an University of Science and Technology (XUST), No. 58, Yanta Mid. Rd., Xi’an 710054, China
Shugang Li: School of Safety Science and Engineering, Xi’an University of Science and Technology (XUST), No. 58, Yanta Mid. Rd., Xi’an 710054, China
Haifei Lin: School of Safety Science and Engineering, Xi’an University of Science and Technology (XUST), No. 58, Yanta Mid. Rd., Xi’an 710054, China
Yang Ding: School of Safety Science and Engineering, Xi’an University of Science and Technology (XUST), No. 58, Yanta Mid. Rd., Xi’an 710054, China
Haiqing Shuang: School of Safety Science and Engineering, Xi’an University of Science and Technology (XUST), No. 58, Yanta Mid. Rd., Xi’an 710054, China
Sibo Liu: School of Safety Science and Engineering, Xi’an University of Science and Technology (XUST), No. 58, Yanta Mid. Rd., Xi’an 710054, China
Yu Tian: School of Safety Science and Engineering, Xi’an University of Science and Technology (XUST), No. 58, Yanta Mid. Rd., Xi’an 710054, China

Energies, 2021, vol. 14, issue 21, 1-21

Abstract: The process of underground coal mining fractures the overlying strata and may provide storage and transportation space for gas by changing the roof rock permeability, which is released by pressure after mining. This paper adopts the experimental method of physical similarity simulation and combines the fractal theory to study the permeability characteristics of the fracture network after mining, and it establishes the fractal permeability equation of pressure-relief gas. The results of the study show that the fracture opening shows a positive correlation with the overburden permeability, whereas the tortuosity of the fracture shows a negative correlation with the overburden permeability. The shape of the high permeability area in the fracture network is found to be similar to the hat-shaped elliptical parabolic zone. In the process of permeability evolution, the key layer structure of the overburden rock is considered as the main factor that affects the trend of change in permeability. Furthermore, based on the above research results, this study developed a targeted design of high-level boreholes in the experimental face and reversed the permeability changes around the drainage borehole. The average error between the actual measured value and the theoretically calculated value is found to be 8.11%. The theoretical model and the permeability evolution law obtained from the research results can provide valuable references and insights into further research on the pressure-relief gas flow model in the goaf.

Keywords: permeability; fractal dimension; overburden fracture; physical similarity simulation; pressure-relief gas; high-level borehole (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/1996-1073/14/21/7031/pdf (application/pdf)
https://www.mdpi.com/1996-1073/14/21/7031/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:14:y:2021:i:21:p:7031-:d:665638

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().