Analysis of the influence of different bedding angles on hydraulic fractures propagation in coal rock
To explore the impact of different bedding angles on the fractures propagation of coal hydraulic fracturing in coal-rock formations, based on the zero thickness Cohesive unit damage criterion, a finite element model of coal and rock hydraulic fracturing fractures propagation at different bedding ang...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Office of Safety in Coal Mines
2025-08-01
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| Series: | Meikuang Anquan |
| Subjects: | |
| Online Access: | https://www.mkaqzz.com/cn/article/doi/10.13347/j.cnki.mkaq.20231905 |
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| Summary: | To explore the impact of different bedding angles on the fractures propagation of coal hydraulic fracturing in coal-rock formations, based on the zero thickness Cohesive unit damage criterion, a finite element model of coal and rock hydraulic fracturing fractures propagation at different bedding angles (0°, 30°, 45°, 60°, 90°) is established. The hydraulic fracturing results at different bedding angles are characterized by hydraulic fracture propagation morphology, the number of branch fractures and joint widths. The hydraulic fracture width and pore pressure of coal rock under different horizontal geo-stress difference at different bedding angles are analyzed and verified in well FG-T29 of Shenfu Block. The results show that when the bedding is 0°, the hydraulic fracture spreads after penetrating the first bedding; when the bedding is 30°, the fractures first pass through the first bedding, extend along the direction of the second bedding, and then turn at the bedding; when the bedding is 45°, the fractures turn after extending along the first layer; the cracks of 60° and 90° bedding did not extend to the bedding surface. Compared with the other 4 bedding angles, 45° bedding coal rock has the largest number of branch fractures (15) and the largest fracture width (6.19 mm) during fracturing. With the increase of horizontal geo-stress difference, the crack width of hydraulic fracture decreases and the initiation pressure increases for all the five bedding angles. |
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| ISSN: | 1003-496X |