Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths
Both bulk stress (σii) and stress path (SP) significantly affect the transportation characteristics of deep gas during reservoir pressure depletion. Therefore, the experimental study of horizontal stress unloading on seepage behavior of gas-bearing coal under constant σii-constraints is performed. T...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2024-11-01
|
| Series: | International Journal of Mining Science and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2095268624001538 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1846099118057848832 |
|---|---|
| author | Chao Liu Jiahao Zhang Songwei Wu Jinghua Qi Beichen Yu Liang Wang |
| author_facet | Chao Liu Jiahao Zhang Songwei Wu Jinghua Qi Beichen Yu Liang Wang |
| author_sort | Chao Liu |
| collection | DOAJ |
| description | Both bulk stress (σii) and stress path (SP) significantly affect the transportation characteristics of deep gas during reservoir pressure depletion. Therefore, the experimental study of horizontal stress unloading on seepage behavior of gas-bearing coal under constant σii-constraints is performed. The results show that coal permeability is affected by horizontal stress anisotropy (σH≠σh), and the contribution of minor horizontal stress to permeability is related to the differential response of horizontal strain. The slippage phenomenon is prominent in deep high-stress regime, especially in low reservoir pressure. σii and SP jointly determine the manifestation of slippage effect and the strength of stress sensitivity (γ) of permeability. Deep reservoir implies an incremental percentage of slip-based permeability, and SP weakens the slippage effect by changing the elastic–plastic state of coal. However, γ is negatively correlated with slippage effect. From the Walsh model, narrow (low aspect-ratio) fractures within the coal under unloading SP became the main channel for gas seepage, and bring the effective stress coefficient of permeability (χ) less than 1 for both low-stress elastic and high-stress damaged coal. With the raise of the effective stress, the effect of pore-lined clay particles on permeability was enhanced, inducing an increase in χ for high-stress elastic coal. |
| format | Article |
| id | doaj-art-c9d0f7c79659475d8dc9ace3a520686f |
| institution | Kabale University |
| issn | 2095-2686 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | International Journal of Mining Science and Technology |
| spelling | doaj-art-c9d0f7c79659475d8dc9ace3a520686f2025-01-01T05:10:06ZengElsevierInternational Journal of Mining Science and Technology2095-26862024-11-01341114951508Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading pathsChao Liu0Jiahao Zhang1Songwei Wu2Jinghua Qi3Beichen Yu4Liang Wang5School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China; State Key Laboratory of Mining Disaster Prevention and Control, Ministry of Education, Shandong University of Science and Technology, Qingdao 266590, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaSchool of Safety Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaSchool of Safety Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaKey Laboratory of Theory and Technology on Coal and Rock Dynamic Disaster Prevention and Control, National Mine Safety Administration, China University of Mining and Technology, Xuzhou 221116, China; State Key Laboratory of Coal Mine Disaster Prevention and Control, China University of Mining and Technology, Xuzhou 221116, China; Corresponding author.Both bulk stress (σii) and stress path (SP) significantly affect the transportation characteristics of deep gas during reservoir pressure depletion. Therefore, the experimental study of horizontal stress unloading on seepage behavior of gas-bearing coal under constant σii-constraints is performed. The results show that coal permeability is affected by horizontal stress anisotropy (σH≠σh), and the contribution of minor horizontal stress to permeability is related to the differential response of horizontal strain. The slippage phenomenon is prominent in deep high-stress regime, especially in low reservoir pressure. σii and SP jointly determine the manifestation of slippage effect and the strength of stress sensitivity (γ) of permeability. Deep reservoir implies an incremental percentage of slip-based permeability, and SP weakens the slippage effect by changing the elastic–plastic state of coal. However, γ is negatively correlated with slippage effect. From the Walsh model, narrow (low aspect-ratio) fractures within the coal under unloading SP became the main channel for gas seepage, and bring the effective stress coefficient of permeability (χ) less than 1 for both low-stress elastic and high-stress damaged coal. With the raise of the effective stress, the effect of pore-lined clay particles on permeability was enhanced, inducing an increase in χ for high-stress elastic coal.http://www.sciencedirect.com/science/article/pii/S2095268624001538True triaxial stress pathConstant bulk stressHorizontal stressEffective stress coefficient of permeabilitySlippage effect |
| spellingShingle | Chao Liu Jiahao Zhang Songwei Wu Jinghua Qi Beichen Yu Liang Wang Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths International Journal of Mining Science and Technology True triaxial stress path Constant bulk stress Horizontal stress Effective stress coefficient of permeability Slippage effect |
| title | Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths |
| title_full | Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths |
| title_fullStr | Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths |
| title_full_unstemmed | Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths |
| title_short | Experimental study on permeability evolution of deep high-stressed coal under major horizontal stress unloading paths |
| title_sort | experimental study on permeability evolution of deep high stressed coal under major horizontal stress unloading paths |
| topic | True triaxial stress path Constant bulk stress Horizontal stress Effective stress coefficient of permeability Slippage effect |
| url | http://www.sciencedirect.com/science/article/pii/S2095268624001538 |
| work_keys_str_mv | AT chaoliu experimentalstudyonpermeabilityevolutionofdeephighstressedcoalundermajorhorizontalstressunloadingpaths AT jiahaozhang experimentalstudyonpermeabilityevolutionofdeephighstressedcoalundermajorhorizontalstressunloadingpaths AT songweiwu experimentalstudyonpermeabilityevolutionofdeephighstressedcoalundermajorhorizontalstressunloadingpaths AT jinghuaqi experimentalstudyonpermeabilityevolutionofdeephighstressedcoalundermajorhorizontalstressunloadingpaths AT beichenyu experimentalstudyonpermeabilityevolutionofdeephighstressedcoalundermajorhorizontalstressunloadingpaths AT liangwang experimentalstudyonpermeabilityevolutionofdeephighstressedcoalundermajorhorizontalstressunloadingpaths |