Influence of local thermal non-equilibrium on enhanced geothermal system
Effective development of hot dry rock depends on complex fracture network formed by the enhanced geothermal system. Different scales of mass and heat transfer environment are formed between tight matrix and different fractures, which leads to the complexity of mass and heat transfer process of porou...
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| Format: | Article |
| Language: | English |
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Science Press (China Science Publishing & Media Ltd.)
2022-11-01
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| Series: | Shenzhen Daxue xuebao. Ligong ban |
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| Online Access: | https://journal.szu.edu.cn/en/#/digest?ArticleID=2473 |
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| _version_ | 1850038127032270848 |
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| author | CHENG Linsong SHI Junjie CAO Renyi YANG Chenxu DU Xulin |
| author_facet | CHENG Linsong SHI Junjie CAO Renyi YANG Chenxu DU Xulin |
| author_sort | CHENG Linsong |
| collection | DOAJ |
| description | Effective development of hot dry rock depends on complex fracture network formed by the enhanced geothermal system. Different scales of mass and heat transfer environment are formed between tight matrix and different fractures, which leads to the complexity of mass and heat transfer process of porous media. In order to analyze the influence of local thermal non-equilibrium on the mass and heat transfer process of complex fracture system, a micro pore scale mass and heat transfer model considering local non-thermal equilibrium is established. The microscopic mechanism of the effect of local non-thermal equilibrium assumption on mass and heat transfer process in matrix-fracture system is revealed. An embedded discrete fracture model considering local thermal non-equilibrium assumption and the solution method are also established. The necessity of considering local thermal non-equilibrium is analyzed by studying the sensitivity of formation physical parameters. The results show that ignoring the local thermal non-equilibrium assumption will underestimate the rock temperature near the fracture zone and overestimate the fluid temperature in the heat transfer front zone. The effect of local thermal non-equilibrium on the enhanced geothermal system is mainly reflected in the early stage of injection. The higher the injection intensity, the lower the matrix fracture permeability, the greater the matrix fracture porosity difference, the greater the rock thermal diffusion coefficient, the smaller the convective heat transfer coefficient, the more it is necessary to consider the local thermal non-equilibrium assumption. The research results can provide reference for the collection and collation of field data. |
| format | Article |
| id | doaj-art-7be54aa25e3c4b89b6021cd16954cf59 |
| institution | DOAJ |
| issn | 1000-2618 |
| language | English |
| publishDate | 2022-11-01 |
| publisher | Science Press (China Science Publishing & Media Ltd.) |
| record_format | Article |
| series | Shenzhen Daxue xuebao. Ligong ban |
| spelling | doaj-art-7be54aa25e3c4b89b6021cd16954cf592025-08-20T02:56:39ZengScience Press (China Science Publishing & Media Ltd.)Shenzhen Daxue xuebao. Ligong ban1000-26182022-11-0139664965910.3724/SP.J.1249.2022.066491000-2618（2022）06-0649-11Influence of local thermal non-equilibrium on enhanced geothermal systemCHENG Linsong0SHI Junjie1CAO Renyi2YANG Chenxu3DU Xulin4College of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102249, P.R.ChinaCollege of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102249, P.R.ChinaCollege of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102249, P.R.ChinaCollege of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102249, P.R.ChinaCollege of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102249, P.R.ChinaEffective development of hot dry rock depends on complex fracture network formed by the enhanced geothermal system. Different scales of mass and heat transfer environment are formed between tight matrix and different fractures, which leads to the complexity of mass and heat transfer process of porous media. In order to analyze the influence of local thermal non-equilibrium on the mass and heat transfer process of complex fracture system, a micro pore scale mass and heat transfer model considering local non-thermal equilibrium is established. The microscopic mechanism of the effect of local non-thermal equilibrium assumption on mass and heat transfer process in matrix-fracture system is revealed. An embedded discrete fracture model considering local thermal non-equilibrium assumption and the solution method are also established. The necessity of considering local thermal non-equilibrium is analyzed by studying the sensitivity of formation physical parameters. The results show that ignoring the local thermal non-equilibrium assumption will underestimate the rock temperature near the fracture zone and overestimate the fluid temperature in the heat transfer front zone. The effect of local thermal non-equilibrium on the enhanced geothermal system is mainly reflected in the early stage of injection. The higher the injection intensity, the lower the matrix fracture permeability, the greater the matrix fracture porosity difference, the greater the rock thermal diffusion coefficient, the smaller the convective heat transfer coefficient, the more it is necessary to consider the local thermal non-equilibrium assumption. The research results can provide reference for the collection and collation of field data.https://journal.szu.edu.cn/en/#/digest?ArticleID=2473geothermicsoil, gas and water seepage mechanicstight reservoirlocal non-thermal equilibriumembedded discrete fracture modelnumerical simulationtight matrixcomplex fracturesenhanced geothermal system |
| spellingShingle | CHENG Linsong SHI Junjie CAO Renyi YANG Chenxu DU Xulin Influence of local thermal non-equilibrium on enhanced geothermal system Shenzhen Daxue xuebao. Ligong ban geothermics oil, gas and water seepage mechanics tight reservoir local non-thermal equilibrium embedded discrete fracture model numerical simulation tight matrix complex fractures enhanced geothermal system |
| title | Influence of local thermal non-equilibrium on enhanced geothermal system |
| title_full | Influence of local thermal non-equilibrium on enhanced geothermal system |
| title_fullStr | Influence of local thermal non-equilibrium on enhanced geothermal system |
| title_full_unstemmed | Influence of local thermal non-equilibrium on enhanced geothermal system |
| title_short | Influence of local thermal non-equilibrium on enhanced geothermal system |
| title_sort | influence of local thermal non equilibrium on enhanced geothermal system |
| topic | geothermics oil, gas and water seepage mechanics tight reservoir local non-thermal equilibrium embedded discrete fracture model numerical simulation tight matrix complex fractures enhanced geothermal system |
| url | https://journal.szu.edu.cn/en/#/digest?ArticleID=2473 |
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