The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone Reservoirs
Abstract Tortuosity has different definitions that are used by scientists and engineers to describe various fluid‐related processes in porous media. Two of the most commonly used definitions are electrical (describing the electrical current flow process) and diffusion (related to the molecular diffu...
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Wiley
2024-06-01
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| Series: | Water Resources Research |
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| Online Access: | https://doi.org/10.1029/2023WR037031 |
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| author | Mahmoud Elsayed Ammar El‐Husseiny Hyung Kwak Abdulrauf R. Adebayo Mohamed Mahmoud |
| author_facet | Mahmoud Elsayed Ammar El‐Husseiny Hyung Kwak Abdulrauf R. Adebayo Mohamed Mahmoud |
| author_sort | Mahmoud Elsayed |
| collection | DOAJ |
| description | Abstract Tortuosity has different definitions that are used by scientists and engineers to describe various fluid‐related processes in porous media. Two of the most commonly used definitions are electrical (describing the electrical current flow process) and diffusion (related to the molecular diffusive flow process) tortuosity. In this study, we investigate the impact of minerology (presence of clay) and fluid conductivity on the electrical‐diffusion tortuosity relationship. That is: whether or not electrical and diffusion tortuosity have one‐to‐one relationship in sandstones. Two groups of samples were used: clean Fontainebleau sandstones and clayey sandstones. Electrical resistivity was measured using four‐electrode method to obtain electrical formation factor and calculate the electrical tortuosity (τe) using a model that is applicable for consolidated rocks. Pulsed field gradient nuclear magnetic resonance (PFG NMR) measurements were employed to quantify diffusion tortuosity (τD). At lower fluid conductivity (3 S/m), our results show that τD ≈τe for clean sandstones, while τe << τD is observed for clayey sandstones. We propose that mineralogy has direct impact on the τe−τD relationship: the presence of clay minerals added surface conductivity which contributed to underestimating the intrinsic formation factor (F′) and consequently reducing τe. As the fluid conductivity increases, τe converges to τD until reaching the high salinity limit at which F′ is obtained and τD becomes in good agreement with τe for the clayey sandstone. The NMR diffusion approach presented here shows the potential of estimating F′ without the need for multi‐salinity data which can contribute to improved permeability prediction. |
| format | Article |
| id | doaj-art-986c5b541cd846ccb34a0a092b74accf |
| institution | DOAJ |
| issn | 0043-1397 1944-7973 |
| language | English |
| publishDate | 2024-06-01 |
| publisher | Wiley |
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| series | Water Resources Research |
| spelling | doaj-art-986c5b541cd846ccb34a0a092b74accf2025-08-20T03:22:18ZengWileyWater Resources Research0043-13971944-79732024-06-01606n/an/a10.1029/2023WR037031The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone ReservoirsMahmoud Elsayed0Ammar El‐Husseiny1Hyung Kwak2Abdulrauf R. Adebayo3Mohamed Mahmoud4College of Petroleum Engineering and Geosciences King Fahd University of Petroleum and Minerals Dhahran Saudi ArabiaCollege of Petroleum Engineering and Geosciences King Fahd University of Petroleum and Minerals Dhahran Saudi ArabiaSaudi Aramco Dhahran Saudi ArabiaCollege of Petroleum Engineering and Geosciences King Fahd University of Petroleum and Minerals Dhahran Saudi ArabiaCollege of Petroleum Engineering and Geosciences King Fahd University of Petroleum and Minerals Dhahran Saudi ArabiaAbstract Tortuosity has different definitions that are used by scientists and engineers to describe various fluid‐related processes in porous media. Two of the most commonly used definitions are electrical (describing the electrical current flow process) and diffusion (related to the molecular diffusive flow process) tortuosity. In this study, we investigate the impact of minerology (presence of clay) and fluid conductivity on the electrical‐diffusion tortuosity relationship. That is: whether or not electrical and diffusion tortuosity have one‐to‐one relationship in sandstones. Two groups of samples were used: clean Fontainebleau sandstones and clayey sandstones. Electrical resistivity was measured using four‐electrode method to obtain electrical formation factor and calculate the electrical tortuosity (τe) using a model that is applicable for consolidated rocks. Pulsed field gradient nuclear magnetic resonance (PFG NMR) measurements were employed to quantify diffusion tortuosity (τD). At lower fluid conductivity (3 S/m), our results show that τD ≈τe for clean sandstones, while τe << τD is observed for clayey sandstones. We propose that mineralogy has direct impact on the τe−τD relationship: the presence of clay minerals added surface conductivity which contributed to underestimating the intrinsic formation factor (F′) and consequently reducing τe. As the fluid conductivity increases, τe converges to τD until reaching the high salinity limit at which F′ is obtained and τD becomes in good agreement with τe for the clayey sandstone. The NMR diffusion approach presented here shows the potential of estimating F′ without the need for multi‐salinity data which can contribute to improved permeability prediction.https://doi.org/10.1029/2023WR037031sandstoneclaystortuosityresistivityPFG NMR |
| spellingShingle | Mahmoud Elsayed Ammar El‐Husseiny Hyung Kwak Abdulrauf R. Adebayo Mohamed Mahmoud The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone Reservoirs Water Resources Research sandstone clays tortuosity resistivity PFG NMR |
| title | The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone Reservoirs |
| title_full | The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone Reservoirs |
| title_fullStr | The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone Reservoirs |
| title_full_unstemmed | The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone Reservoirs |
| title_short | The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone Reservoirs |
| title_sort | impact of clay and fluid conductivity on the electrical diffusion tortuosity correlations in sandstone reservoirs |
| topic | sandstone clays tortuosity resistivity PFG NMR |
| url | https://doi.org/10.1029/2023WR037031 |
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