Numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seams
Abstract Gas disasters are a major factor influencing safe production in mines: Gas extraction can reduce the gas content in coal seams, providing a guarantee of safer production. The parameters for gas extraction are the primary factors influencing the effectiveness thereof. Aiming at the creep pro...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2019-10-01
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| Series: | Energy Science & Engineering |
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| Online Access: | https://doi.org/10.1002/ese3.377 |
| _version_ | 1818300429635682304 |
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| author | Pan Wei Changwen Huang Xuelong Li Shoujian Peng Yanan Lu |
| author_facet | Pan Wei Changwen Huang Xuelong Li Shoujian Peng Yanan Lu |
| author_sort | Pan Wei |
| collection | DOAJ |
| description | Abstract Gas disasters are a major factor influencing safe production in mines: Gas extraction can reduce the gas content in coal seams, providing a guarantee of safer production. The parameters for gas extraction are the primary factors influencing the effectiveness thereof. Aiming at the creep properties of soft coal, a fluid‐solid coupling mathematical model considering creep properties of coal was established based on dynamic evolution equation for permeability considering the effects of matrix shrinkage and effective stress. Additionally, by utilizing COMSOL Multiphysics software, the gas extractions from a single borehole and multiple boreholes were calculated. Moreover, the parameters for gas extraction were optimized and applied and tested in field conditions. The result showed the reduction in gas pressure around the boreholes was larger than that from a single borehole when conducting gas extraction from multiple boreholes. The borehole spacing when extracting gas in coal seams by drilling multiple boreholes should be more than twice that of the effective drainage radius. The optimal borehole spacing ranged from 3.2 to 4.2 m for gas extraction lasting 180 d. Numerical simulation was carried out to ascertain the distribution of stress on coal around a roadway. The result revealed that the damage radius of the roadway was 11.8 m, and a reasonable hole‐sealing depth was 12 m. On condition that the borehole spacing during gas extraction from multiple boreholes was 4 m, the reasonable pre‐extraction time was 180 days taking the gas pressure being reduced to <0.74 MPa as a critical point. Furthermore, the gas content, the amount of extracted gas, etc, in a working face after the parameters for gas extraction were optimized were measured. The result suggested that the effect of gas extraction after optimizing parameters conformed to industry standards. |
| first_indexed | 2024-12-13T05:06:59Z |
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| id | doaj.art-04cdda9d207a4b70aca3f04d781c14bb |
| institution | Directory Open Access Journal |
| issn | 2050-0505 |
| language | English |
| last_indexed | 2024-12-13T05:06:59Z |
| publishDate | 2019-10-01 |
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| series | Energy Science & Engineering |
| spelling | doaj.art-04cdda9d207a4b70aca3f04d781c14bb2022-12-21T23:58:39ZengWileyEnergy Science & Engineering2050-05052019-10-01751632164810.1002/ese3.377Numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seamsPan Wei0Changwen Huang1Xuelong Li2Shoujian Peng3Yanan Lu4State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University Chongqing ChinaChongqing Energy Technology Investment Group Company Limited Chongqing ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University Chongqing ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University Chongqing ChinaCollege of Safety Science and Engineering Xi’an University of Science and Technology Xi’an ChinaAbstract Gas disasters are a major factor influencing safe production in mines: Gas extraction can reduce the gas content in coal seams, providing a guarantee of safer production. The parameters for gas extraction are the primary factors influencing the effectiveness thereof. Aiming at the creep properties of soft coal, a fluid‐solid coupling mathematical model considering creep properties of coal was established based on dynamic evolution equation for permeability considering the effects of matrix shrinkage and effective stress. Additionally, by utilizing COMSOL Multiphysics software, the gas extractions from a single borehole and multiple boreholes were calculated. Moreover, the parameters for gas extraction were optimized and applied and tested in field conditions. The result showed the reduction in gas pressure around the boreholes was larger than that from a single borehole when conducting gas extraction from multiple boreholes. The borehole spacing when extracting gas in coal seams by drilling multiple boreholes should be more than twice that of the effective drainage radius. The optimal borehole spacing ranged from 3.2 to 4.2 m for gas extraction lasting 180 d. Numerical simulation was carried out to ascertain the distribution of stress on coal around a roadway. The result revealed that the damage radius of the roadway was 11.8 m, and a reasonable hole‐sealing depth was 12 m. On condition that the borehole spacing during gas extraction from multiple boreholes was 4 m, the reasonable pre‐extraction time was 180 days taking the gas pressure being reduced to <0.74 MPa as a critical point. Furthermore, the gas content, the amount of extracted gas, etc, in a working face after the parameters for gas extraction were optimized were measured. The result suggested that the effect of gas extraction after optimizing parameters conformed to industry standards.https://doi.org/10.1002/ese3.377fluid‐solid couplinggas extractionnumerical simulationparameter optimizationsoft coal |
| spellingShingle | Pan Wei Changwen Huang Xuelong Li Shoujian Peng Yanan Lu Numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seams Energy Science & Engineering fluid‐solid coupling gas extraction numerical simulation parameter optimization soft coal |
| title | Numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seams |
| title_full | Numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seams |
| title_fullStr | Numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seams |
| title_full_unstemmed | Numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seams |
| title_short | Numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seams |
| title_sort | numerical simulation of boreholes for gas extraction and effective range of gas extraction in soft coal seams |
| topic | fluid‐solid coupling gas extraction numerical simulation parameter optimization soft coal |
| url | https://doi.org/10.1002/ese3.377 |
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