Furkejuvvon:
| Váldodahkkit: | , , , |
|---|---|
| Materiálatiipa: | Recurso digital |
| Giella: | eaŋgalasgiella |
| Almmustuhtton: |
Zenodo
2023
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| Fáttát: | |
| Liŋkkat: | https://doi.org/10.5281/zenodo.15876758 |
| Fáddágilkorat: |
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Sisdoallologahallan:
- <p>Archie equation is the foundation of modern petrophysics and parameters m, cementation exponent, and n, saturation exponent, are critical inputs of Archie equation. Traditionally, m and n are obtained from core analysis, which are available only in cored formations, and the process is costly and time consuming, especially for n which is known to be sensitive to rocks wettability and flooding cycle, drainage or imbibition. Multi-frequency dielectric data is used to derive m and n and its accuracy is investigated to assess its downhole applicability for different flooding regimes. To derive Archie m and n from multi-frequency dielectric data, we obtained dielectric constant using an open-ended coaxial laboratory test probe operating between 10 MHz and 1 GHz on clean outcrop core samples. For data interpretation, we used an approach which considers matrix, hydrocarbon and water as three different phases in dielectric data processing, by applying effective medium theory on the formation rock in two steps: first between water and hydrocarbon resulting in an effective fluid permittivity, then second between effective fluid permittivity and matrix. For validation purposes, we applied this technique on core samples after drainage and imbibition cycles and compare our dielectric results with m and n obtained from resistivity core analysis. The derived m and n from dielectric data from drainage core samples show good agreement with the core resistivity data. When compared with data from resistivity tests, the single-phase property m derived from the new method performs much better than that from MN approach. As for the two-phase property n from the primary drainage experiment, a significant improvement is also realized. The findings were consistent for different lithologies, sandstone and carbonate. As of forced imbibition experiment, n exponent shows insignificant hysteresis compared to drainage results as our samples are strongly water-wet and light mineral oil was used for cores desaturation. The derived m and n from dielectric data on imbibition experiments are comparable with core analysis data. However, m exponent derived from dielectric data showed better results from drainage experiment compared to imbibition. Using the new method presented in this study to interpret multi-frequency dielectric data has the potential to be implemented in interpreting downhole dielectric logs for continuous Archie parameters m and n, resolving a long-standing challenge in formation evaluation.</p>