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| DOI | 10.1306/02251917057 |
| Resolution limits of fluid overpressures from mineralogy, porosity, and sonic velocity variations in North Sea mudrocks | |
| Hermanrud C.; Hermanrud C.; Undertun O. | |
| 发表日期 | 2019 |
| ISSN | 0149-1423 |
| 起始页码 | 2665 |
| 结束页码 | 2695 |
| 卷号 | 103期号:11 |
| 英文摘要 | Pore pressure identification in mudrocks largely relies on indirect methods, including analyses of sonic velocity data. The magnitude of pore pressure changes that can be resolved from such data depends on the impact of fluid pressures on well log responses and on the velocity responses to lithological variations that could be mistaken for indications of pore pressure changes. Analysis of relationships between sonic velocity, mineralogy, and porosity from 11 North Sea wells demonstrated porosity variations of up to 5% from the mean value in mudrocks at any given depth between 1 and 3.5 km (3300-11,500 ft). Comparisons of these wells with seven wells from the Norwegian Sea demonstrated that the sonic velocity and density variations are influenced by the content of silica with a biogenic origin, but that they can otherwise not, in general, be related to mineralogy and pore pressure variations. The sonic velocity deviations from the mean value are of the same magnitude as those that would be caused by porosity changes of-8% in mudrocks of uniform lithology. Furthermore, the deviations are not significantly reduced when the velocity data are compensated for changes in density (porosity). Detection limits for mechanically compacting mudrocks that are at their maximum effective stress are equivalent to static mud density changes of 0.1-0.15 g/cm3. These numbers apply to mudrocks with similar lithological variability to those analyzed in our data set but should be much higher when significant amounts of silica with a biogenic origin are present. © 2019 The American Association of Petroleum Geologists. All rights reserved. |
| 关键词 | LithologyMineralsPore pressurePorositySilicaUnderwater mineralogyWell loggingDensity variationsLithological variabilityPorosity changesPorosity variationsPressure identificationPressure variationsResolution limitsVelocity responseVelocitycompactiondetection methodeffective stressfluid pressurelithologymineralogymudstoneoverpressurepore pressureporositysonic boomwell loggingArctic OceanAtlantic OceanNorth SeaNorwegian Sea |
| 语种 | 英语 |
| 来源机构 | AAPG Bulletin |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/131699 |
| 推荐引用方式 GB/T 7714 | Hermanrud C.,Hermanrud C.,Undertun O.. Resolution limits of fluid overpressures from mineralogy, porosity, and sonic velocity variations in North Sea mudrocks[J]. AAPG Bulletin,2019,103(11). |
| APA | Hermanrud C.,Hermanrud C.,&Undertun O..(2019).Resolution limits of fluid overpressures from mineralogy, porosity, and sonic velocity variations in North Sea mudrocks.,103(11). |
| MLA | Hermanrud C.,et al."Resolution limits of fluid overpressures from mineralogy, porosity, and sonic velocity variations in North Sea mudrocks".103.11(2019). |
| 条目包含的文件 | 条目无相关文件。 | |||||
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