A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal Mines
When coal bed methane (CBM) drainage boreholes cross fractured, soft, or water-swelling strata, they collapse and block frequently. Borehole blockages result in a rapid decrease in CBM extraction ability, which leads to a reduction in CBM output and threatens coal mine safety production. To solve th...
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MDPI AG
2016-08-01
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| Series: | Energies |
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| Online Access: | http://www.mdpi.com/1996-1073/9/9/698 |
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| author | Zhaolong Ge Kai Deng Yiyu Lu Liang Cheng Shaojie Zuo Xingdi Tian |
| author_facet | Zhaolong Ge Kai Deng Yiyu Lu Liang Cheng Shaojie Zuo Xingdi Tian |
| author_sort | Zhaolong Ge |
| collection | DOAJ |
| description | When coal bed methane (CBM) drainage boreholes cross fractured, soft, or water-swelling strata, they collapse and block frequently. Borehole blockages result in a rapid decrease in CBM extraction ability, which leads to a reduction in CBM output and threatens coal mine safety production. To solve these problems, a novel method that uses a self-propelled water-jet nozzle to dredge blocked boreholes in coal seams has been proposed on the basis of the existing technology. Based on a theoretical analysis of the reason for borehole caving and the theory of blockage removal, we optimized the nozzle inlet pressure and selected an appropriate high-pressure resin pipe. A field experiment on the blockage removal of blocked CBM drainage boreholes using the proposed method was run in the Fengchun coal mine, Qijiang, Chongqing, southwest China. In this field trial, the time spent to unblock a borehole varied between 18.52 and 34.98 min, which is much shorter than using a drilling rig. After blockage removal, the average pure volume of the methane drainage of a single borehole was increased from 0.03 L/min to ~1.91–7.30 L/min, and the methane drainage concentration of a single borehole increased from 5% to ~44%–85%. The extraction effect increased significantly. |
| first_indexed | 2024-04-14T05:05:55Z |
| format | Article |
| id | doaj.art-e52caf4b80fb44bc8945af1ebbaabd53 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-14T05:05:55Z |
| publishDate | 2016-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-e52caf4b80fb44bc8945af1ebbaabd532022-12-22T02:10:41ZengMDPI AGEnergies1996-10732016-08-019969810.3390/en9090698en9090698A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal MinesZhaolong Ge0Kai Deng1Yiyu Lu2Liang Cheng3Shaojie Zuo4Xingdi Tian5State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaSongzao Coal-Electricity Limited Liability Company, Chongqing 401445, ChinaWhen coal bed methane (CBM) drainage boreholes cross fractured, soft, or water-swelling strata, they collapse and block frequently. Borehole blockages result in a rapid decrease in CBM extraction ability, which leads to a reduction in CBM output and threatens coal mine safety production. To solve these problems, a novel method that uses a self-propelled water-jet nozzle to dredge blocked boreholes in coal seams has been proposed on the basis of the existing technology. Based on a theoretical analysis of the reason for borehole caving and the theory of blockage removal, we optimized the nozzle inlet pressure and selected an appropriate high-pressure resin pipe. A field experiment on the blockage removal of blocked CBM drainage boreholes using the proposed method was run in the Fengchun coal mine, Qijiang, Chongqing, southwest China. In this field trial, the time spent to unblock a borehole varied between 18.52 and 34.98 min, which is much shorter than using a drilling rig. After blockage removal, the average pure volume of the methane drainage of a single borehole was increased from 0.03 L/min to ~1.91–7.30 L/min, and the methane drainage concentration of a single borehole increased from 5% to ~44%–85%. The extraction effect increased significantly.http://www.mdpi.com/1996-1073/9/9/698coal bed methane (CBM)blocked boreholesself-propelled nozzlehigh-pressure water jet |
| spellingShingle | Zhaolong Ge Kai Deng Yiyu Lu Liang Cheng Shaojie Zuo Xingdi Tian A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal Mines Energies coal bed methane (CBM) blocked boreholes self-propelled nozzle high-pressure water jet |
| title | A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal Mines |
| title_full | A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal Mines |
| title_fullStr | A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal Mines |
| title_full_unstemmed | A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal Mines |
| title_short | A Novel Method for Borehole Blockage Removal and Experimental Study on a Hydraulic Self-Propelled Nozzle in Underground Coal Mines |
| title_sort | novel method for borehole blockage removal and experimental study on a hydraulic self propelled nozzle in underground coal mines |
| topic | coal bed methane (CBM) blocked boreholes self-propelled nozzle high-pressure water jet |
| url | http://www.mdpi.com/1996-1073/9/9/698 |
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