N2 influences on CH4 accumulation and displacement in shale by molecular dynamics
Abstract N2 is generally employed as a displacement agent to enhance gas recovery in shale gas-bearing reservoirs. However, the primary displacement mechanism in the subsurface still needs to be clarified due to the characteristics of shale reservoirs with low porosity and abundant nanopores. This s...
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Nature Portfolio
2025-01-01
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| Series: | Scientific Reports |
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| Online Access: | https://doi.org/10.1038/s41598-024-82136-w |
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| author | Jiawei Li Yue Lang Binhui Li Yong Liu Zhejun Pan Sheikh S. Rahman |
| author_facet | Jiawei Li Yue Lang Binhui Li Yong Liu Zhejun Pan Sheikh S. Rahman |
| author_sort | Jiawei Li |
| collection | DOAJ |
| description | Abstract N2 is generally employed as a displacement agent to enhance gas recovery in shale gas-bearing reservoirs. However, the primary displacement mechanism in the subsurface still needs to be clarified due to the characteristics of shale reservoirs with low porosity and abundant nanopores. This study employs the Molecular Dynamics (MD) simulation method to investigate the effects of N2 on the CH4 accumulation and displacement processes by adopting practical conditions in the subsurface environment. In equilibrium MD simulation processes, including the N2 from outside and inner kerogen matrix, keeping the gas ratio of 1:3 for CH4 and N2, the displacement is 52.4% and 65.3%, respectively, which suggests that CH4 cannot be entirely displaced by surrounding N2 particles, owing to the strong interaction between CH4 and the kerogen matrix. For the straightforward displacement process by N2, the displacement efficiency is enhanced by 71.7% at the 1:1 gas ratio. Another case of N2, in which generation is accompanied by displacement processes, at the ratio 1:2 for N2:CH4, shows a 47.1% displacement efficiency. This work evidences that the straightforward displacement process is more efficient on CH4 displacement, which enhances CH4 production at a pronounced scale and sheds light on the N2 displacement process in industrial shale gas reservoir production. |
| format | Article |
| id | doaj-art-0cf214af652c453bb7f7efcdd8c2648d |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
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| series | Scientific Reports |
| spelling | doaj-art-0cf214af652c453bb7f7efcdd8c2648d2025-01-19T12:21:31ZengNature PortfolioScientific Reports2045-23222025-01-0115111410.1038/s41598-024-82136-wN2 influences on CH4 accumulation and displacement in shale by molecular dynamicsJiawei Li0Yue Lang1Binhui Li2Yong Liu3Zhejun Pan4Sheikh S. Rahman5State Key Laboratory of Continental Shale OilDaqing Oilfield Exploration and Development Research InstituteState Key Laboratory of Continental Shale OilState Key Laboratory of Continental Shale OilState Key Laboratory of Continental Shale Oil School of Minerals and Energy Resources Engineering, University of New South WalesAbstract N2 is generally employed as a displacement agent to enhance gas recovery in shale gas-bearing reservoirs. However, the primary displacement mechanism in the subsurface still needs to be clarified due to the characteristics of shale reservoirs with low porosity and abundant nanopores. This study employs the Molecular Dynamics (MD) simulation method to investigate the effects of N2 on the CH4 accumulation and displacement processes by adopting practical conditions in the subsurface environment. In equilibrium MD simulation processes, including the N2 from outside and inner kerogen matrix, keeping the gas ratio of 1:3 for CH4 and N2, the displacement is 52.4% and 65.3%, respectively, which suggests that CH4 cannot be entirely displaced by surrounding N2 particles, owing to the strong interaction between CH4 and the kerogen matrix. For the straightforward displacement process by N2, the displacement efficiency is enhanced by 71.7% at the 1:1 gas ratio. Another case of N2, in which generation is accompanied by displacement processes, at the ratio 1:2 for N2:CH4, shows a 47.1% displacement efficiency. This work evidences that the straightforward displacement process is more efficient on CH4 displacement, which enhances CH4 production at a pronounced scale and sheds light on the N2 displacement process in industrial shale gas reservoir production.https://doi.org/10.1038/s41598-024-82136-wShale gasN2 displacementRecovery efficiencySelf-diffusion coefficient |
| spellingShingle | Jiawei Li Yue Lang Binhui Li Yong Liu Zhejun Pan Sheikh S. Rahman N2 influences on CH4 accumulation and displacement in shale by molecular dynamics Scientific Reports Shale gas N2 displacement Recovery efficiency Self-diffusion coefficient |
| title | N2 influences on CH4 accumulation and displacement in shale by molecular dynamics |
| title_full | N2 influences on CH4 accumulation and displacement in shale by molecular dynamics |
| title_fullStr | N2 influences on CH4 accumulation and displacement in shale by molecular dynamics |
| title_full_unstemmed | N2 influences on CH4 accumulation and displacement in shale by molecular dynamics |
| title_short | N2 influences on CH4 accumulation and displacement in shale by molecular dynamics |
| title_sort | n2 influences on ch4 accumulation and displacement in shale by molecular dynamics |
| topic | Shale gas N2 displacement Recovery efficiency Self-diffusion coefficient |
| url | https://doi.org/10.1038/s41598-024-82136-w |
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