Comprehensive Characterization and Metamorphic Control Analysis of Full Apertures in Different Coal Ranks within Deep Coal Seams
The pore fracture structure of deep coal reservoirs is crucial for evaluating the potential of deep coalbed methane resources, conducting exploration and development, and controlling coal mine gas disasters. Mercury intrusion porosimetry, the liquid nitrogen method, and the low-temperature carbon di...
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2024-09-01
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| author | Qi Li Yong Wu Lei Qiao |
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| description | The pore fracture structure of deep coal reservoirs is crucial for evaluating the potential of deep coalbed methane resources, conducting exploration and development, and controlling coal mine gas disasters. Mercury intrusion porosimetry, the liquid nitrogen method, and the low-temperature carbon dioxide adsorption method were used to study the full pore size structure and pore fractal characteristics of different coal grades in deep coal and comprehensively characterize the pore structure of kilometer-level coal mining. The sponge, Frenkel–Halsey–Hill (FHH), and density function models were applied to comprehensively analyze the pore complexity of coal, and the influence of metamorphic degree on pore size structure was evaluated. The distribution relationship of pore volume in different stages of coal samples was macropore→mesopore→micropore, and macropores had the best connectivity. Micropores and mesopores had the largest specific surface area, and the development of micropores and microcracks controlled the deep gas adsorption performance. The micropore volume and specific surface area both revealed a nonlinear decreasing trend with the increase in volatile matter, and coal metamorphism promoted the development of micropores. The pore volume and specific surface area of mesopores and macropores decreased first and then increased in a “U” shape with increasing volatile matter. In contrast, the fractal dimension D<sub>1</sub> revealed an inverted U shape with increasing volatile matter, followed by a decrease. The D<sub>2</sub> value decreased nonlinearly with increasing volatile matter, whereas the D<sub>3</sub> value increased nonlinearly with increasing volatile matter. The degree of metamorphism increased, and the microporous structure became more regular. |
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| spelling | doaj-art-11d6681e484e4df6baf586dc960104be2025-08-20T01:55:58ZengMDPI AGApplied Sciences2076-34172024-09-011418856610.3390/app14188566Comprehensive Characterization and Metamorphic Control Analysis of Full Apertures in Different Coal Ranks within Deep Coal SeamsQi Li0Yong Wu1Lei Qiao2College of Environment and Civil Engineering, Chengdu University of Technology, Chengdu 610059, ChinaCollege of Environment and Civil Engineering, Chengdu University of Technology, Chengdu 610059, ChinaKey Laboratory of Rock Mechanics and Geohazards of Zhejiang Province, Shaoxing 312000, ChinaThe pore fracture structure of deep coal reservoirs is crucial for evaluating the potential of deep coalbed methane resources, conducting exploration and development, and controlling coal mine gas disasters. Mercury intrusion porosimetry, the liquid nitrogen method, and the low-temperature carbon dioxide adsorption method were used to study the full pore size structure and pore fractal characteristics of different coal grades in deep coal and comprehensively characterize the pore structure of kilometer-level coal mining. The sponge, Frenkel–Halsey–Hill (FHH), and density function models were applied to comprehensively analyze the pore complexity of coal, and the influence of metamorphic degree on pore size structure was evaluated. The distribution relationship of pore volume in different stages of coal samples was macropore→mesopore→micropore, and macropores had the best connectivity. Micropores and mesopores had the largest specific surface area, and the development of micropores and microcracks controlled the deep gas adsorption performance. The micropore volume and specific surface area both revealed a nonlinear decreasing trend with the increase in volatile matter, and coal metamorphism promoted the development of micropores. The pore volume and specific surface area of mesopores and macropores decreased first and then increased in a “U” shape with increasing volatile matter. In contrast, the fractal dimension D<sub>1</sub> revealed an inverted U shape with increasing volatile matter, followed by a decrease. The D<sub>2</sub> value decreased nonlinearly with increasing volatile matter, whereas the D<sub>3</sub> value increased nonlinearly with increasing volatile matter. The degree of metamorphism increased, and the microporous structure became more regular.https://www.mdpi.com/2076-3417/14/18/8566different coal gradesfull aperture structurepore fractalmercury intrusion methodliquid nitrogen methodlow-temperature carbon dioxide adsorption method |
| spellingShingle | Qi Li Yong Wu Lei Qiao Comprehensive Characterization and Metamorphic Control Analysis of Full Apertures in Different Coal Ranks within Deep Coal Seams Applied Sciences different coal grades full aperture structure pore fractal mercury intrusion method liquid nitrogen method low-temperature carbon dioxide adsorption method |
| title | Comprehensive Characterization and Metamorphic Control Analysis of Full Apertures in Different Coal Ranks within Deep Coal Seams |
| title_full | Comprehensive Characterization and Metamorphic Control Analysis of Full Apertures in Different Coal Ranks within Deep Coal Seams |
| title_fullStr | Comprehensive Characterization and Metamorphic Control Analysis of Full Apertures in Different Coal Ranks within Deep Coal Seams |
| title_full_unstemmed | Comprehensive Characterization and Metamorphic Control Analysis of Full Apertures in Different Coal Ranks within Deep Coal Seams |
| title_short | Comprehensive Characterization and Metamorphic Control Analysis of Full Apertures in Different Coal Ranks within Deep Coal Seams |
| title_sort | comprehensive characterization and metamorphic control analysis of full apertures in different coal ranks within deep coal seams |
| topic | different coal grades full aperture structure pore fractal mercury intrusion method liquid nitrogen method low-temperature carbon dioxide adsorption method |
| url | https://www.mdpi.com/2076-3417/14/18/8566 |
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