Three-Water Differential Parallel Conductivity Saturation Model of Low-Permeability Tight Oil and Gas Reservoirs
Addressing the poor performance of existing logging saturation models in low-permeability tight sandstone reservoirs and the challenges in determining model parameters, this study investigates the pore structure and fluid occurrence state of such reservoirs through petrophysical experiments and digi...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-04-01
|
| Series: | Energies |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1073/17/7/1726 |
| _version_ | 1827286818187378688 |
|---|---|
| author | Xiangyang Hu Renjie Cheng Hengrong Zhang Jitian Zhu Peng Chi Jianmeng Sun |
| author_facet | Xiangyang Hu Renjie Cheng Hengrong Zhang Jitian Zhu Peng Chi Jianmeng Sun |
| author_sort | Xiangyang Hu |
| collection | DOAJ |
| description | Addressing the poor performance of existing logging saturation models in low-permeability tight sandstone reservoirs and the challenges in determining model parameters, this study investigates the pore structure and fluid occurrence state of such reservoirs through petrophysical experiments and digital rock visualization simulations. The aim is to uncover new insights into fluid occurrence state and electrical conduction properties and subsequently develop a low-permeability tight sandstone reservoir saturation model with easily determinable parameters. This model is suitable for practical oilfield exploration and development applications with high evaluation accuracy. The research findings reveal that such reservoirs comprise three types of formation water: strongly bound water, weakly bound water, and free water. These types are found in non-connected micropores, poorly connected mesopores where fluid flow occurs when the pressure differential exceeds the critical value, and well-connected macropores. Furthermore, the three types of formation water demonstrate variations in their electrical conduction contributions. By inversely solving rock electrical experiment data, it was determined that for a single sample, the overall cementation index is the highest, followed by the cementation index of pore throats containing strongly bound water, and the lowest for the pore throats with free water. Building on the aforementioned insights, this study develops a parallel electrical pore cementation index term, <i>ϕ</i><sup><i>m</i>′</sup>, to account for the differences among the three types of water and introduces a parallel electrical saturation model suitable for logging evaluation of low-permeability tight oil and gas reservoirs. This model demonstrated positive application effects in the logging evaluation of low-permeability tight gas reservoirs in a specific basin in the Chinese offshore area, thereby confirming the advantages of its application. |
| first_indexed | 2024-04-24T10:45:18Z |
| format | Article |
| id | doaj.art-38ce030ee5c54ca3acf294bdbdd2ec08 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-24T10:45:18Z |
| publishDate | 2024-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-38ce030ee5c54ca3acf294bdbdd2ec082024-04-12T13:18:11ZengMDPI AGEnergies1996-10732024-04-01177172610.3390/en17071726Three-Water Differential Parallel Conductivity Saturation Model of Low-Permeability Tight Oil and Gas ReservoirsXiangyang Hu0Renjie Cheng1Hengrong Zhang2Jitian Zhu3Peng Chi4Jianmeng Sun5Zhanjiang Branch, CNOOC China Limited, Zhanjiang 524057, ChinaZhanjiang Branch, CNOOC China Limited, Zhanjiang 524057, ChinaZhanjiang Branch, CNOOC China Limited, Zhanjiang 524057, ChinaZhanjiang Branch, CNOOC China Limited, Zhanjiang 524057, ChinaSchool of Geosciences, China University of Petroleum (East China), Qingdao 266580, ChinaSchool of Geosciences, China University of Petroleum (East China), Qingdao 266580, ChinaAddressing the poor performance of existing logging saturation models in low-permeability tight sandstone reservoirs and the challenges in determining model parameters, this study investigates the pore structure and fluid occurrence state of such reservoirs through petrophysical experiments and digital rock visualization simulations. The aim is to uncover new insights into fluid occurrence state and electrical conduction properties and subsequently develop a low-permeability tight sandstone reservoir saturation model with easily determinable parameters. This model is suitable for practical oilfield exploration and development applications with high evaluation accuracy. The research findings reveal that such reservoirs comprise three types of formation water: strongly bound water, weakly bound water, and free water. These types are found in non-connected micropores, poorly connected mesopores where fluid flow occurs when the pressure differential exceeds the critical value, and well-connected macropores. Furthermore, the three types of formation water demonstrate variations in their electrical conduction contributions. By inversely solving rock electrical experiment data, it was determined that for a single sample, the overall cementation index is the highest, followed by the cementation index of pore throats containing strongly bound water, and the lowest for the pore throats with free water. Building on the aforementioned insights, this study develops a parallel electrical pore cementation index term, <i>ϕ</i><sup><i>m</i>′</sup>, to account for the differences among the three types of water and introduces a parallel electrical saturation model suitable for logging evaluation of low-permeability tight oil and gas reservoirs. This model demonstrated positive application effects in the logging evaluation of low-permeability tight gas reservoirs in a specific basin in the Chinese offshore area, thereby confirming the advantages of its application.https://www.mdpi.com/1996-1073/17/7/1726low-permeability tight sandstone reservoirscomplex pore structurefluid occurrence stateelectrical conductivity propertieslogging saturation model |
| spellingShingle | Xiangyang Hu Renjie Cheng Hengrong Zhang Jitian Zhu Peng Chi Jianmeng Sun Three-Water Differential Parallel Conductivity Saturation Model of Low-Permeability Tight Oil and Gas Reservoirs Energies low-permeability tight sandstone reservoirs complex pore structure fluid occurrence state electrical conductivity properties logging saturation model |
| title | Three-Water Differential Parallel Conductivity Saturation Model of Low-Permeability Tight Oil and Gas Reservoirs |
| title_full | Three-Water Differential Parallel Conductivity Saturation Model of Low-Permeability Tight Oil and Gas Reservoirs |
| title_fullStr | Three-Water Differential Parallel Conductivity Saturation Model of Low-Permeability Tight Oil and Gas Reservoirs |
| title_full_unstemmed | Three-Water Differential Parallel Conductivity Saturation Model of Low-Permeability Tight Oil and Gas Reservoirs |
| title_short | Three-Water Differential Parallel Conductivity Saturation Model of Low-Permeability Tight Oil and Gas Reservoirs |
| title_sort | three water differential parallel conductivity saturation model of low permeability tight oil and gas reservoirs |
| topic | low-permeability tight sandstone reservoirs complex pore structure fluid occurrence state electrical conductivity properties logging saturation model |
| url | https://www.mdpi.com/1996-1073/17/7/1726 |
| work_keys_str_mv | AT xiangyanghu threewaterdifferentialparallelconductivitysaturationmodeloflowpermeabilitytightoilandgasreservoirs AT renjiecheng threewaterdifferentialparallelconductivitysaturationmodeloflowpermeabilitytightoilandgasreservoirs AT hengrongzhang threewaterdifferentialparallelconductivitysaturationmodeloflowpermeabilitytightoilandgasreservoirs AT jitianzhu threewaterdifferentialparallelconductivitysaturationmodeloflowpermeabilitytightoilandgasreservoirs AT pengchi threewaterdifferentialparallelconductivitysaturationmodeloflowpermeabilitytightoilandgasreservoirs AT jianmengsun threewaterdifferentialparallelconductivitysaturationmodeloflowpermeabilitytightoilandgasreservoirs |