Pore-scale modeling of pore structure properties and wettability effect on permeability of low-rank coal
Permeability is a key parameter for coalbed methane development. Although the absolute permeability of coal has been extensively studied, wettability and pore structure properties continue to challenge the microscopic description of water-gas flow in coal. For this purpose, we reconstructed the micr...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-05-01
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| Series: | International Journal of Mining Science and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2095268623000393 |
| _version_ | 1797813708227870720 |
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| author | Xiangjie Qin Jianchao Cai Gang Wang |
| author_facet | Xiangjie Qin Jianchao Cai Gang Wang |
| author_sort | Xiangjie Qin |
| collection | DOAJ |
| description | Permeability is a key parameter for coalbed methane development. Although the absolute permeability of coal has been extensively studied, wettability and pore structure properties continue to challenge the microscopic description of water-gas flow in coal. For this purpose, we reconstructed the microstructures of low-rank coal using micro-computed tomography (micro-CT) images. Pore geometry and pore-throat parameters are introduced to establish a relationship with absolute permeability. A dual-porosity pore network model is developed to study water-gas displacement under different wetting and pore structure properties. Results show that absolute permeability is significantly affected by pore geometry and can be described using a binary quadratic function of porosity and fractal dimension. Water-gas relative permeability varies significantly and the residual gas saturation is lower; the crossover saturation first decreased and then increased with increasing porosity under hydrophobic conditions. While the water relative permeability is lower and a certain amount of gas is trapped in complex pore-throat networks; the crossover saturation is higher under hydrophilic conditions. Models with large percolating porosity and well-developed pore networks have high displacement efficiency due to low capillary resistance and avoidance of trapping. This work provides a systematic description of absolute permeability and water-gas relative permeability in coal microstructure for enhanced gas recovery. |
| first_indexed | 2024-03-13T07:56:45Z |
| format | Article |
| id | doaj.art-122713b605754372bfb54fafced51385 |
| institution | Directory Open Access Journal |
| issn | 2095-2686 |
| language | English |
| last_indexed | 2024-03-13T07:56:45Z |
| publishDate | 2023-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | International Journal of Mining Science and Technology |
| spelling | doaj.art-122713b605754372bfb54fafced513852023-06-02T04:23:01ZengElsevierInternational Journal of Mining Science and Technology2095-26862023-05-01335573584Pore-scale modeling of pore structure properties and wettability effect on permeability of low-rank coalXiangjie Qin0Jianchao Cai1Gang Wang2State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, ChinaState Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, ChinaState Key Laboratory of Mining Disaster Prevention and Control Cofounded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, China; Corresponding author.Permeability is a key parameter for coalbed methane development. Although the absolute permeability of coal has been extensively studied, wettability and pore structure properties continue to challenge the microscopic description of water-gas flow in coal. For this purpose, we reconstructed the microstructures of low-rank coal using micro-computed tomography (micro-CT) images. Pore geometry and pore-throat parameters are introduced to establish a relationship with absolute permeability. A dual-porosity pore network model is developed to study water-gas displacement under different wetting and pore structure properties. Results show that absolute permeability is significantly affected by pore geometry and can be described using a binary quadratic function of porosity and fractal dimension. Water-gas relative permeability varies significantly and the residual gas saturation is lower; the crossover saturation first decreased and then increased with increasing porosity under hydrophobic conditions. While the water relative permeability is lower and a certain amount of gas is trapped in complex pore-throat networks; the crossover saturation is higher under hydrophilic conditions. Models with large percolating porosity and well-developed pore networks have high displacement efficiency due to low capillary resistance and avoidance of trapping. This work provides a systematic description of absolute permeability and water-gas relative permeability in coal microstructure for enhanced gas recovery.http://www.sciencedirect.com/science/article/pii/S2095268623000393Micro-CTPermeabilityWetting conditionPore structure propertiesWater-gas flow |
| spellingShingle | Xiangjie Qin Jianchao Cai Gang Wang Pore-scale modeling of pore structure properties and wettability effect on permeability of low-rank coal International Journal of Mining Science and Technology Micro-CT Permeability Wetting condition Pore structure properties Water-gas flow |
| title | Pore-scale modeling of pore structure properties and wettability effect on permeability of low-rank coal |
| title_full | Pore-scale modeling of pore structure properties and wettability effect on permeability of low-rank coal |
| title_fullStr | Pore-scale modeling of pore structure properties and wettability effect on permeability of low-rank coal |
| title_full_unstemmed | Pore-scale modeling of pore structure properties and wettability effect on permeability of low-rank coal |
| title_short | Pore-scale modeling of pore structure properties and wettability effect on permeability of low-rank coal |
| title_sort | pore scale modeling of pore structure properties and wettability effect on permeability of low rank coal |
| topic | Micro-CT Permeability Wetting condition Pore structure properties Water-gas flow |
| url | http://www.sciencedirect.com/science/article/pii/S2095268623000393 |
| work_keys_str_mv | AT xiangjieqin porescalemodelingofporestructurepropertiesandwettabilityeffectonpermeabilityoflowrankcoal AT jianchaocai porescalemodelingofporestructurepropertiesandwettabilityeffectonpermeabilityoflowrankcoal AT gangwang porescalemodelingofporestructurepropertiesandwettabilityeffectonpermeabilityoflowrankcoal |