Evolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal cores
Objective and MethodsThe in situ gas pressure of coal seams represents a crucial parameter for the safe production of coal mines and the assessment of coalbed methane (CBM) resources. To overcome current limitations in determining the in situ gas pressure, such as prolonged measurement cycles and th...
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Editorial Office of Coal Geology & Exploration
2025-04-01
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| Series: | Meitian dizhi yu kantan |
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| Online Access: | http://www.mtdzykt.com/article/doi/10.12363/issn.1001-1986.24.09.0613 |
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| author | Mingzhong GAO Jie SONG Pengfei CUI Yongcheng LI Zhipeng WANG Xuemin ZHOU Ju LI Zongxin HAO Haichun HAO |
| author_facet | Mingzhong GAO Jie SONG Pengfei CUI Yongcheng LI Zhipeng WANG Xuemin ZHOU Ju LI Zongxin HAO Haichun HAO |
| author_sort | Mingzhong GAO |
| collection | DOAJ |
| description | Objective and MethodsThe in situ gas pressure of coal seams represents a crucial parameter for the safe production of coal mines and the assessment of coalbed methane (CBM) resources. To overcome current limitations in determining the in situ gas pressure, such as prolonged measurement cycles and the influence of multiple parameters on the measurement results, this study conducted isothermal adsorption and volumetric expansion desorption experiments on pressure-retaining coal cores with varying moisture contents using a self-constructed experimental system for gas pressure evolution in pressure-retaining coal cores. As a result, the evolutionary pattern of gas pressure in pressure-retaining coal cores was determined. Accordingly, following the theoretical calculation principle of in situ gas pressure in coal seams, formed by the in situ pressure- and gas-retaining coring process for deep coal seams, this study proposed a correction model for gas pressure calculation that considered moisture content and verified its reliability. Results and ConclusionsThe results indicate that: (1) Influenced by high gas pressure, the gas pressure within the pressure-preserved space more easily reaches a new equilibrium. During the isothermal adsorption process, the gas pressure exhibits a staged evolution characteristic, where the gas pressure in the pressure-preserved coal core first rapidly decreases to a certain value, then increases before gradually stabilizing. (2) Due to the pore characteristics of the coal sample being dominated by mesopores and having a large micropore volume, the higher the moisture content of coal leads to greater resistance to gas adsorption, resulting the longer the equilibrium time and the lower the adsorption pressure drop. (3) The gas pressure of the coal samples was calculated based on the expansion desorption experiments of pressure-preserved coal cores with different moisture contents. The average relative errors of the gas pressure calculation results under various moisture contents were 2.22%, 1.29%, 0.39%, and 0.80%, respectively. The corrected gas pressure calculation method demonstrated high accuracy. The proposed approach offers promising potential as a reliable, efficient, and accurate means for determining of in-situ coalbed gas pressure. |
| format | Article |
| id | doaj-art-a3f1669631ca46ce83006626b006817a |
| institution | OA Journals |
| issn | 1001-1986 |
| language | zho |
| publishDate | 2025-04-01 |
| publisher | Editorial Office of Coal Geology & Exploration |
| record_format | Article |
| series | Meitian dizhi yu kantan |
| spelling | doaj-art-a3f1669631ca46ce83006626b006817a2025-08-20T02:19:45ZzhoEditorial Office of Coal Geology & ExplorationMeitian dizhi yu kantan1001-19862025-04-01534182910.12363/issn.1001-1986.24.09.061324-09-0613-Gao-MingzhongEvolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal coresMingzhong GAO0Jie SONG1Pengfei CUI2Yongcheng LI3Zhipeng WANG4Xuemin ZHOU5Ju LI6Zongxin HAOHaichun HAO7State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Shenzhen University, Shenzhen 518060, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Shenzhen University, Shenzhen 518060, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Shenzhen University, Shenzhen 518060, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Shenzhen University, Shenzhen 518060, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Shenzhen University, Shenzhen 518060, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Shenzhen University, Shenzhen 518060, ChinaCollege of Water Resource and Hydropower, Sichuan University, Chengdu 610065, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Shenzhen University, Shenzhen 518060, ChinaObjective and MethodsThe in situ gas pressure of coal seams represents a crucial parameter for the safe production of coal mines and the assessment of coalbed methane (CBM) resources. To overcome current limitations in determining the in situ gas pressure, such as prolonged measurement cycles and the influence of multiple parameters on the measurement results, this study conducted isothermal adsorption and volumetric expansion desorption experiments on pressure-retaining coal cores with varying moisture contents using a self-constructed experimental system for gas pressure evolution in pressure-retaining coal cores. As a result, the evolutionary pattern of gas pressure in pressure-retaining coal cores was determined. Accordingly, following the theoretical calculation principle of in situ gas pressure in coal seams, formed by the in situ pressure- and gas-retaining coring process for deep coal seams, this study proposed a correction model for gas pressure calculation that considered moisture content and verified its reliability. Results and ConclusionsThe results indicate that: (1) Influenced by high gas pressure, the gas pressure within the pressure-preserved space more easily reaches a new equilibrium. During the isothermal adsorption process, the gas pressure exhibits a staged evolution characteristic, where the gas pressure in the pressure-preserved coal core first rapidly decreases to a certain value, then increases before gradually stabilizing. (2) Due to the pore characteristics of the coal sample being dominated by mesopores and having a large micropore volume, the higher the moisture content of coal leads to greater resistance to gas adsorption, resulting the longer the equilibrium time and the lower the adsorption pressure drop. (3) The gas pressure of the coal samples was calculated based on the expansion desorption experiments of pressure-preserved coal cores with different moisture contents. The average relative errors of the gas pressure calculation results under various moisture contents were 2.22%, 1.29%, 0.39%, and 0.80%, respectively. The corrected gas pressure calculation method demonstrated high accuracy. The proposed approach offers promising potential as a reliable, efficient, and accurate means for determining of in-situ coalbed gas pressure.http://www.mtdzykt.com/article/doi/10.12363/issn.1001-1986.24.09.0613pressure- and gas- retaining coringmoisture contentin-situ gas pressurepressure calculationpressure evolution |
| spellingShingle | Mingzhong GAO Jie SONG Pengfei CUI Yongcheng LI Zhipeng WANG Xuemin ZHOU Ju LI Zongxin HAO Haichun HAO Evolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal cores Meitian dizhi yu kantan pressure- and gas- retaining coring moisture content in-situ gas pressure pressure calculation pressure evolution |
| title | Evolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal cores |
| title_full | Evolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal cores |
| title_fullStr | Evolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal cores |
| title_full_unstemmed | Evolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal cores |
| title_short | Evolutionary pattern and a calculation method of in situ gas pressure based on pressure-retaining coal cores |
| title_sort | evolutionary pattern and a calculation method of in situ gas pressure based on pressure retaining coal cores |
| topic | pressure- and gas- retaining coring moisture content in-situ gas pressure pressure calculation pressure evolution |
| url | http://www.mtdzykt.com/article/doi/10.12363/issn.1001-1986.24.09.0613 |
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