Research and Application of Low-Velocity Nonlinear Seepage Model for Unconventional Mixed Tight Reservoir
Due to factors such as low porosity and permeability, thin sand body thickness, and strong interlayer heterogeneity, the fluid flow in the tight reservoir (beach-bar sandstone reservoir) exhibits obvious nonlinear seepage characteristics. Considering the time-varying physical parameters of different...
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2025-07-01
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| author | Li Ma Cong Lu Jianchun Guo Bo Zeng Shiqian Xu |
| author_facet | Li Ma Cong Lu Jianchun Guo Bo Zeng Shiqian Xu |
| author_sort | Li Ma |
| collection | DOAJ |
| description | Due to factors such as low porosity and permeability, thin sand body thickness, and strong interlayer heterogeneity, the fluid flow in the tight reservoir (beach-bar sandstone reservoir) exhibits obvious nonlinear seepage characteristics. Considering the time-varying physical parameters of different types of sand bodies, a nonlinear seepage coefficient is derived based on permeability and capillary force, and a low-velocity nonlinear seepage model for beach bar sand reservoirs is established. Based on core displacement experiments of different types of sand bodies, the low-velocity nonlinear seepage coefficient was fitted and numerical simulation of low-velocity nonlinear seepage in beach-bar sandstone reservoirs was carried out. The research results show that the displacement pressure and flow rate of low-permeability tight reservoirs exhibit a significant nonlinear relationship. The lower the permeability and the smaller the displacement pressure, the more significant the nonlinear seepage characteristics. Compared to the bar sand reservoir, the water injection pressure in the tight reservoir of the beach sand is higher. In the nonlinear seepage model, the bottom hole pressure of the water injection well increases by 10.56% compared to the linear model, indicating that water injection is more difficult in the beach sand reservoir. Compared to matrix type beach sand reservoirs, natural fractures can effectively reduce the impact of fluid nonlinear seepage characteristics on the injection and production process of beach sand reservoirs. Based on the nonlinear seepage characteristics, the beach-bar sandstone reservoir can be divided into four flow zones during the injection production process, including linear seepage zone, nonlinear seepage zone, non-flow zone affected by pressure, and non-flow zone not affected by pressure. The research results can effectively guide the development of beach-bar sandstone reservoirs, reduce the impact of low-speed nonlinear seepage, and enhance oil recovery. |
| format | Article |
| id | doaj-art-5f2053a527464f118cb9cb7c02beea7e |
| institution | DOAJ |
| issn | 1996-1073 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
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| series | Energies |
| spelling | doaj-art-5f2053a527464f118cb9cb7c02beea7e2025-08-20T03:07:57ZengMDPI AGEnergies1996-10732025-07-011814378910.3390/en18143789Research and Application of Low-Velocity Nonlinear Seepage Model for Unconventional Mixed Tight ReservoirLi Ma0Cong Lu1Jianchun Guo2Bo Zeng3Shiqian Xu4Research Institute of Shale Gas, PetroChina Southwest Oil & Gas Field Company, Chengdu 610051, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, ChinaResearch Institute of Shale Gas, PetroChina Southwest Oil & Gas Field Company, Chengdu 610051, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, ChinaDue to factors such as low porosity and permeability, thin sand body thickness, and strong interlayer heterogeneity, the fluid flow in the tight reservoir (beach-bar sandstone reservoir) exhibits obvious nonlinear seepage characteristics. Considering the time-varying physical parameters of different types of sand bodies, a nonlinear seepage coefficient is derived based on permeability and capillary force, and a low-velocity nonlinear seepage model for beach bar sand reservoirs is established. Based on core displacement experiments of different types of sand bodies, the low-velocity nonlinear seepage coefficient was fitted and numerical simulation of low-velocity nonlinear seepage in beach-bar sandstone reservoirs was carried out. The research results show that the displacement pressure and flow rate of low-permeability tight reservoirs exhibit a significant nonlinear relationship. The lower the permeability and the smaller the displacement pressure, the more significant the nonlinear seepage characteristics. Compared to the bar sand reservoir, the water injection pressure in the tight reservoir of the beach sand is higher. In the nonlinear seepage model, the bottom hole pressure of the water injection well increases by 10.56% compared to the linear model, indicating that water injection is more difficult in the beach sand reservoir. Compared to matrix type beach sand reservoirs, natural fractures can effectively reduce the impact of fluid nonlinear seepage characteristics on the injection and production process of beach sand reservoirs. Based on the nonlinear seepage characteristics, the beach-bar sandstone reservoir can be divided into four flow zones during the injection production process, including linear seepage zone, nonlinear seepage zone, non-flow zone affected by pressure, and non-flow zone not affected by pressure. The research results can effectively guide the development of beach-bar sandstone reservoirs, reduce the impact of low-speed nonlinear seepage, and enhance oil recovery.https://www.mdpi.com/1996-1073/18/14/3789tight reservoirbeach-bar sandstonenonlinear seepagepermeabilitynatural fractures |
| spellingShingle | Li Ma Cong Lu Jianchun Guo Bo Zeng Shiqian Xu Research and Application of Low-Velocity Nonlinear Seepage Model for Unconventional Mixed Tight Reservoir Energies tight reservoir beach-bar sandstone nonlinear seepage permeability natural fractures |
| title | Research and Application of Low-Velocity Nonlinear Seepage Model for Unconventional Mixed Tight Reservoir |
| title_full | Research and Application of Low-Velocity Nonlinear Seepage Model for Unconventional Mixed Tight Reservoir |
| title_fullStr | Research and Application of Low-Velocity Nonlinear Seepage Model for Unconventional Mixed Tight Reservoir |
| title_full_unstemmed | Research and Application of Low-Velocity Nonlinear Seepage Model for Unconventional Mixed Tight Reservoir |
| title_short | Research and Application of Low-Velocity Nonlinear Seepage Model for Unconventional Mixed Tight Reservoir |
| title_sort | research and application of low velocity nonlinear seepage model for unconventional mixed tight reservoir |
| topic | tight reservoir beach-bar sandstone nonlinear seepage permeability natural fractures |
| url | https://www.mdpi.com/1996-1073/18/14/3789 |
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