1887

Abstract

Summary

Mudstones are characterized by their tight matrix and are therefore of interest in various industries, including the petroleum and underground repository industry. These clay-rich rocks often show dynamic elastic anisotropy, which causes significant problems in geophysical interpretations. In addition, pore water has a significant effect on the bulk properties of mudstones. However, the degree of saturation is often not reported in the literature. This study investigates the impact of water saturation on the elastic anisotropy of the Whitby Mudstone. Four core plugs with different water saturations were deformed until failure and tested ultrasonically at effective confining pressure conditions of 25 MPa. P-wave and S-wave velocities were monitored along the symmetry axis, across the core diameter, and at ~49˚ to the horizontal bedding plane to calculate the full elastic tensor and subsequently the Thomsen anisotropy parameters. The degree of saturation highly affects the rock strength and static elastic properties and leads to significant changes in the elastic anisotropy parameters.

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/content/papers/10.3997/2214-4609.201900288
2019-04-28
2024-04-24
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References

  1. Dewhurst, David N., and Anthony F.Siggins
    [2006] Impact of Fabric, Microcracks and Stress Field on Shale Anisotropy. Geophysical Journal International165 (1): 135–48. https://doi.org/10.1111/j.1365-246X.2006.02834.x.
    [Google Scholar]
  2. Ghorbani, Ahmad, MariaZamora, and PhilippeCosenza
    [2009] Effects of Desiccation on the Elastic Wave Velocities of Clay-Rocks.” International Journal of Rock Mechanics and Mining Sciences46 (8): 1267–72. https://doi.org/10.1016/j.ijrmms.2009.01.009.
    [Google Scholar]
  3. Hornby, Brian E.
    [1998] Experimental Laboratory Determination of the Dynamic Elastic Properties of Wet, Drained Shales. Journal of Geophysical Research103 (97): 945–64.
    [Google Scholar]
  4. Hudson, J. A.
    [1981] Wave Speeds and Attenuation of Elastic Waves in Material Containing Cracks. Geophysical Journal of the Royal Astronomical Society64 (1): 133–50. https://doi.org/10.1111/j.1365-246X.1981.tb02662.x.
    [Google Scholar]
  5. Jones, Leonie E. A., and Herbert F.Wang
    [1981] Ultrasonic Velocities in Cretaceous Shales from the Williston Basin. Geophysics46 (3): 288–97. https://doi.org/10.1190/1.1441199.
    [Google Scholar]
  6. Nadri, Dariush, JoëlSarout, AndrejBóna, and DavidDewhurst
    [2012] Estimation of the Anisotropy Parameters of Transversely Isotropic Shales with a Tilted Symmetry Axis. Geophysical Journal International190 (2): 1197–1203. https://doi.org/10.1111/j.1365-246X.2012.05545.x.
    [Google Scholar]
  7. Ramosda Silva, Mikaël, ChristianSchroeder, and JeanClaude Verbrugge
    [2008] Unsaturated Rock Mechanics Applied to a Low-Porosity Shale. Engineering Geology97 (1–2): 42–52. https://doi.org/10.1016/j.enggeo.2007.12.003.
    [Google Scholar]
  8. Thomsen, Leon
    [1986] Weak Elastic Anisotropy. Geophysics51 (10) (5): 1954–66. https://doi.org/10.1190/1.1442051.
    [Google Scholar]
  9. Vernik, Lev, and ANur
    [1992] Ultrasonic Velocity and Anisotropy of Hydrocarbon Source Rocks. Geophysics57 (5) (5): 727–35. https://doi.org/10.1190/1.1443286.
    [Google Scholar]
  10. Yurikov, Alexey, MaximLebedev, and MarinaPervukhina
    [2018] Water Retention Effects on the Elastic Properties of Opalinus Shale. Geophysical Propspecting1. https://doi.org/10.1111/13652478.12673.
    [Google Scholar]
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