Characteristics Evolution of Multiscale Structures in Deep Coal under Liquid Nitrogen Freeze-Thaw Cycles
Liquid nitrogen freeze-thaw fracturing has attracted more and more attention in improving the coal reservoir permeability. In order to reveal the impact of liquid nitrogen freeze-thaw on the multiscale structure of deep coal, the multiscale structure evolution law of deep and shallow coal samples fr...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2021-01-01
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| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2021/8921533 |
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| _version_ | 1850214717994303488 |
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| author | Yingfeng Sun Yixin Zhao Yulin Li Nima Noraei Danesh Zetian Zhang |
| author_facet | Yingfeng Sun Yixin Zhao Yulin Li Nima Noraei Danesh Zetian Zhang |
| author_sort | Yingfeng Sun |
| collection | DOAJ |
| description | Liquid nitrogen freeze-thaw fracturing has attracted more and more attention in improving the coal reservoir permeability. In order to reveal the impact of liquid nitrogen freeze-thaw on the multiscale structure of deep coal, the multiscale structure evolution law of deep and shallow coal samples from the same seam in the Qinshui coalfield during the liquid nitrogen freeze-thaw cycling was investigated using NMR T2 spectrum, NMRI, and SEM. The connectivity between mesopores and macropores in deep and shallow coal is improved after liquid nitrogen freeze-thaw cycles. The influence of liquid nitrogen freeze-thaw cycles on the structure evolution of deep and shallow coal is the formation and expansion of microscopic fractures. The initial NMR porosity of deep coal is lower than that of shallow coal from the same coalfield and coal seam. The NMR porosity of both the deep and shallow coal samples increases with the increase of the number of freeze-thaw cycles, and the NMR porosity growth rate of the deep sample is lower than that of the shallow sample. |
| format | Article |
| id | doaj-art-8649dd86a6e748b7a04a4cdcfbda4337 |
| institution | OA Journals |
| issn | 1468-8115 1468-8123 |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geofluids |
| spelling | doaj-art-8649dd86a6e748b7a04a4cdcfbda43372025-08-20T02:08:49ZengWileyGeofluids1468-81151468-81232021-01-01202110.1155/2021/89215338921533Characteristics Evolution of Multiscale Structures in Deep Coal under Liquid Nitrogen Freeze-Thaw CyclesYingfeng Sun0Yixin Zhao1Yulin Li2Nima Noraei Danesh3Zetian Zhang4School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaBeijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing 100083, ChinaSchool of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, ChinaSchool of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, ChinaKey Laboratory of Deep Earth Science and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, ChinaLiquid nitrogen freeze-thaw fracturing has attracted more and more attention in improving the coal reservoir permeability. In order to reveal the impact of liquid nitrogen freeze-thaw on the multiscale structure of deep coal, the multiscale structure evolution law of deep and shallow coal samples from the same seam in the Qinshui coalfield during the liquid nitrogen freeze-thaw cycling was investigated using NMR T2 spectrum, NMRI, and SEM. The connectivity between mesopores and macropores in deep and shallow coal is improved after liquid nitrogen freeze-thaw cycles. The influence of liquid nitrogen freeze-thaw cycles on the structure evolution of deep and shallow coal is the formation and expansion of microscopic fractures. The initial NMR porosity of deep coal is lower than that of shallow coal from the same coalfield and coal seam. The NMR porosity of both the deep and shallow coal samples increases with the increase of the number of freeze-thaw cycles, and the NMR porosity growth rate of the deep sample is lower than that of the shallow sample.http://dx.doi.org/10.1155/2021/8921533 |
| spellingShingle | Yingfeng Sun Yixin Zhao Yulin Li Nima Noraei Danesh Zetian Zhang Characteristics Evolution of Multiscale Structures in Deep Coal under Liquid Nitrogen Freeze-Thaw Cycles Geofluids |
| title | Characteristics Evolution of Multiscale Structures in Deep Coal under Liquid Nitrogen Freeze-Thaw Cycles |
| title_full | Characteristics Evolution of Multiscale Structures in Deep Coal under Liquid Nitrogen Freeze-Thaw Cycles |
| title_fullStr | Characteristics Evolution of Multiscale Structures in Deep Coal under Liquid Nitrogen Freeze-Thaw Cycles |
| title_full_unstemmed | Characteristics Evolution of Multiscale Structures in Deep Coal under Liquid Nitrogen Freeze-Thaw Cycles |
| title_short | Characteristics Evolution of Multiscale Structures in Deep Coal under Liquid Nitrogen Freeze-Thaw Cycles |
| title_sort | characteristics evolution of multiscale structures in deep coal under liquid nitrogen freeze thaw cycles |
| url | http://dx.doi.org/10.1155/2021/8921533 |
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