Experimental Investigation on Permeability and Mechanical Deformation of Coal Containing Gas under Load
Coalbed effective permeability is widely used as a primary index to evaluate gas-drainage effect in CBM exploitation field. However, it seems to be difficult to obtain by the reason of dynamic change in close relationship with crustal stress, methane pressure, porosity, and adsorption. Due to their...
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| Format: | Article |
| Language: | English |
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Wiley
2018-01-01
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| Series: | Advances in Civil Engineering |
| Online Access: | http://dx.doi.org/10.1155/2018/7341523 |
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| author | Runsheng Lv Bing Li Zhimin Song Gaofeng Liu |
| author_facet | Runsheng Lv Bing Li Zhimin Song Gaofeng Liu |
| author_sort | Runsheng Lv |
| collection | DOAJ |
| description | Coalbed effective permeability is widely used as a primary index to evaluate gas-drainage effect in CBM exploitation field. However, it seems to be difficult to obtain by the reason of dynamic change in close relationship with crustal stress, methane pressure, porosity, and adsorption. Due to their dissimilar adsorption properties and tectonic deformation degrees, different types of coal containing gas have various stress-strain and gas seepage curves. The paper presents the experimental investigations of the dynamic relationship between coal permeability and deformation under load. In this work, stress-strain and permeability investigations were performed using anthracite lump with a vitrinite reflectance of about 3.24% at various pressures and temperatures. The permeability (including the initial, minimum, and maximum) decreased with increasing temperature. At a constant confining pressure, the strains in different directions almost all increased with increasing axial stress and decreased with increasing pore methane pressure during the prefracture stage. At a constant pore pressure, the compression strength of the coal specimens increased approximately linearly during the prefracture stage and sharply decreased during the postfracture stage, while the permeability decreased rapidly and then increased slowly during the prefracture and remained stable during the postfracture stage. The permeability of the coal specimens mainly depended on the inner fissures. The permeability was greater during the postfracture than that during the prefracture stage. At the same temperature, the gas seepage curve of each coal specimen could be divided into three sections: decreasing, increasing, and constant sections. The necessary time for the permeability to reach a steady state increased as the confining and pore pressures increased. At high confining pressures (i.e., 6 MPa and 8 MPa), no significant differences between the methane seepage velocities of the specimens were evident, and their seepage curves were similar to prefracture. However, clear differences were observable at the postfracture stage. The seepage abilities of the coal specimens were more sensitive to stress than temperature in the same condition. |
| format | Article |
| id | doaj-art-c4769a40e13446d8a6cf9a973896732f |
| institution | Kabale University |
| issn | 1687-8086 1687-8094 |
| language | English |
| publishDate | 2018-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Civil Engineering |
| spelling | doaj-art-c4769a40e13446d8a6cf9a973896732f2025-02-03T07:24:32ZengWileyAdvances in Civil Engineering1687-80861687-80942018-01-01201810.1155/2018/73415237341523Experimental Investigation on Permeability and Mechanical Deformation of Coal Containing Gas under LoadRunsheng Lv0Bing Li1Zhimin Song2Gaofeng Liu3School of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, ChinaHenan University of Engineering, Zhengzhou 451191, ChinaHenan University of Engineering, Zhengzhou 451191, ChinaSchool of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, ChinaCoalbed effective permeability is widely used as a primary index to evaluate gas-drainage effect in CBM exploitation field. However, it seems to be difficult to obtain by the reason of dynamic change in close relationship with crustal stress, methane pressure, porosity, and adsorption. Due to their dissimilar adsorption properties and tectonic deformation degrees, different types of coal containing gas have various stress-strain and gas seepage curves. The paper presents the experimental investigations of the dynamic relationship between coal permeability and deformation under load. In this work, stress-strain and permeability investigations were performed using anthracite lump with a vitrinite reflectance of about 3.24% at various pressures and temperatures. The permeability (including the initial, minimum, and maximum) decreased with increasing temperature. At a constant confining pressure, the strains in different directions almost all increased with increasing axial stress and decreased with increasing pore methane pressure during the prefracture stage. At a constant pore pressure, the compression strength of the coal specimens increased approximately linearly during the prefracture stage and sharply decreased during the postfracture stage, while the permeability decreased rapidly and then increased slowly during the prefracture and remained stable during the postfracture stage. The permeability of the coal specimens mainly depended on the inner fissures. The permeability was greater during the postfracture than that during the prefracture stage. At the same temperature, the gas seepage curve of each coal specimen could be divided into three sections: decreasing, increasing, and constant sections. The necessary time for the permeability to reach a steady state increased as the confining and pore pressures increased. At high confining pressures (i.e., 6 MPa and 8 MPa), no significant differences between the methane seepage velocities of the specimens were evident, and their seepage curves were similar to prefracture. However, clear differences were observable at the postfracture stage. The seepage abilities of the coal specimens were more sensitive to stress than temperature in the same condition.http://dx.doi.org/10.1155/2018/7341523 |
| spellingShingle | Runsheng Lv Bing Li Zhimin Song Gaofeng Liu Experimental Investigation on Permeability and Mechanical Deformation of Coal Containing Gas under Load Advances in Civil Engineering |
| title | Experimental Investigation on Permeability and Mechanical Deformation of Coal Containing Gas under Load |
| title_full | Experimental Investigation on Permeability and Mechanical Deformation of Coal Containing Gas under Load |
| title_fullStr | Experimental Investigation on Permeability and Mechanical Deformation of Coal Containing Gas under Load |
| title_full_unstemmed | Experimental Investigation on Permeability and Mechanical Deformation of Coal Containing Gas under Load |
| title_short | Experimental Investigation on Permeability and Mechanical Deformation of Coal Containing Gas under Load |
| title_sort | experimental investigation on permeability and mechanical deformation of coal containing gas under load |
| url | http://dx.doi.org/10.1155/2018/7341523 |
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