Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group
In mining areas, utilizing coalbed methane (CBM) wells to extract stress relief coalbed methane from adjacent coal seams is an efficient strategy. To enhance CBM extraction, it is vital to reveal the dynamics of stress and fracture fields evolution and optimization well locations and structure. Taki...
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Editorial Department of Coal Science and Technology
2025-03-01
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| Series: | Meitan kexue jishu |
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| Online Access: | http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-1461 |
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| author | Ang XU Shuxun SANG Xiaozhi ZHOU Sijie HAN Jie CHEN Yunfei FENG Yi LOU Zhihua YAN Wei GAO |
| author_facet | Ang XU Shuxun SANG Xiaozhi ZHOU Sijie HAN Jie CHEN Yunfei FENG Yi LOU Zhihua YAN Wei GAO |
| author_sort | Ang XU |
| collection | DOAJ |
| description | In mining areas, utilizing coalbed methane (CBM) wells to extract stress relief coalbed methane from adjacent coal seams is an efficient strategy. To enhance CBM extraction, it is vital to reveal the dynamics of stress and fracture fields evolution and optimization well locations and structure. Taking No. 221015 coalface in Shanjiaoshu coal mine as the study area. By integrating geo-engineering models and engineering data, the stress distribution within and between the overburden was elucidated, the distribution of fracture and the permeability increased zone in the overburden were elucidated, and the well location, structures and enhancement measures were designed. The research demonstrates that: The frequent alternation of lithological properties in the coal measure strata in the study area enhanced the mining influence on overburden. As the key strata progressively fail, the zone located 5−20 meters above the coalface were the fracture zones, in which a large amount of free methane can be migrated and produced across layers, serving as the primary gas source zone of CBM well. The 20−45 meters interval above the coalface belonged to the microfracture zone in the bending subsidence zone, possessing a gas production potential of nearly 2 000 m3/d from adjacent coal seams within a single layer. In this area, stress relief CBM primarily migrates intra-strata and accumulates methane originating from the fracture zone. Optimal well site locations was enclosed by tangential line of the compaction zone along the direction of the coalface and the center line between tangential line of the compaction zone and the return airway, and boundary lines around fractured zones. Meanwhile, the two - or three-stages structure wells with high strength cement cementing and using reaming or screen suspended completion have good stability, which can guarantee long-term extraction work of CBM well. The optimized extraction well scheme provides technical support for achieving a gas production breakthrough of 35000 m3/d from in mining areas of Qianxi region, significantly mitigating the risk of gas outbursts at the coalface. Based on the geological characteristics of multi-layered superimposed CBM systems, the “multi-usage” mode of the vertical well of “multi-layer fracturing and drainage + mining induced stress relief CBM extraction” can serve as a key development direction of “increasing production and efficiency”. |
| format | Article |
| id | doaj-art-b4a943aa22e1427684fec633c42f9d4f |
| institution | OA Journals |
| issn | 0253-2336 |
| language | zho |
| publishDate | 2025-03-01 |
| publisher | Editorial Department of Coal Science and Technology |
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| series | Meitan kexue jishu |
| spelling | doaj-art-b4a943aa22e1427684fec633c42f9d4f2025-08-20T02:14:50ZzhoEditorial Department of Coal Science and TechnologyMeitan kexue jishu0253-23362025-03-0153338539910.12438/cst.2024-14612024-1461Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam groupAng XU0Shuxun SANG1Xiaozhi ZHOU2Sijie HAN3Jie CHEN4Yunfei FENG5Yi LOU6Zhihua YAN7Wei GAO8Key Laboratory of Coalbed Methane Resource and Reservoir Formation Process, Ministry of Education, Xuzhou 221008, ChinaKey Laboratory of Coalbed Methane Resource and Reservoir Formation Process, Ministry of Education, Xuzhou 221008, ChinaKey Laboratory of Coalbed Methane Resource and Reservoir Formation Process, Ministry of Education, Xuzhou 221008, ChinaCarbon Neutrality Institute, China University of Mining and Technology, Xuzhou, 221008, ChinaKey Laboratory of Coalbed Methane Resource and Reservoir Formation Process, Ministry of Education, Xuzhou 221008, ChinaGuizhou Research Center of Shale Gas and CBM Engineering Technology, Guiyang 550081, ChinaGuizhou Panjiang Coalbed MethaneDevelopment and Utilization Co., Ltd., Guiyang 550081, ChinaKey Laboratory of Coalbed Methane Resource and Reservoir Formation Process, Ministry of Education, Xuzhou 221008, ChinaGuizhou Research Center of Shale Gas and CBM Engineering Technology, Guiyang 550081, ChinaIn mining areas, utilizing coalbed methane (CBM) wells to extract stress relief coalbed methane from adjacent coal seams is an efficient strategy. To enhance CBM extraction, it is vital to reveal the dynamics of stress and fracture fields evolution and optimization well locations and structure. Taking No. 221015 coalface in Shanjiaoshu coal mine as the study area. By integrating geo-engineering models and engineering data, the stress distribution within and between the overburden was elucidated, the distribution of fracture and the permeability increased zone in the overburden were elucidated, and the well location, structures and enhancement measures were designed. The research demonstrates that: The frequent alternation of lithological properties in the coal measure strata in the study area enhanced the mining influence on overburden. As the key strata progressively fail, the zone located 5−20 meters above the coalface were the fracture zones, in which a large amount of free methane can be migrated and produced across layers, serving as the primary gas source zone of CBM well. The 20−45 meters interval above the coalface belonged to the microfracture zone in the bending subsidence zone, possessing a gas production potential of nearly 2 000 m3/d from adjacent coal seams within a single layer. In this area, stress relief CBM primarily migrates intra-strata and accumulates methane originating from the fracture zone. Optimal well site locations was enclosed by tangential line of the compaction zone along the direction of the coalface and the center line between tangential line of the compaction zone and the return airway, and boundary lines around fractured zones. Meanwhile, the two - or three-stages structure wells with high strength cement cementing and using reaming or screen suspended completion have good stability, which can guarantee long-term extraction work of CBM well. The optimized extraction well scheme provides technical support for achieving a gas production breakthrough of 35000 m3/d from in mining areas of Qianxi region, significantly mitigating the risk of gas outbursts at the coalface. Based on the geological characteristics of multi-layered superimposed CBM systems, the “multi-usage” mode of the vertical well of “multi-layer fracturing and drainage + mining induced stress relief CBM extraction” can serve as a key development direction of “increasing production and efficiency”.http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-1461thin to medium thickness coal seam groupsmining areaoverburden “three zones”coalbed methane well optimization design |
| spellingShingle | Ang XU Shuxun SANG Xiaozhi ZHOU Sijie HAN Jie CHEN Yunfei FENG Yi LOU Zhihua YAN Wei GAO Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group Meitan kexue jishu thin to medium thickness coal seam groups mining area overburden “three zones” coalbed methane well optimization design |
| title | Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group |
| title_full | Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group |
| title_fullStr | Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group |
| title_full_unstemmed | Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group |
| title_short | Optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group |
| title_sort | optimal design of coalbed methane wells in mining area with thin to medium thick coal seam group |
| topic | thin to medium thickness coal seam groups mining area overburden “three zones” coalbed methane well optimization design |
| url | http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-1461 |
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