1887
Volume 62, Issue 6
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

The presence of fractures in fluid‐saturated porous rocks is usually associated with strong seismic P‐wave attenuation and velocity dispersion. This energy dissipation can be caused by oscillatory wave‐induced fluid pressure diffusion between the fractures and the host rock, an intrinsic attenuation mechanism generally referred to as wave‐induced fluid flow. Geological observations suggest that fracture surfaces are highly irregular at the millimetre and sub‐millimetre scale, which finds its expression in geometrical and mechanical complexities of the contact area between the fracture faces. It is well known that contact areas strongly affect the overall mechanical fracture properties. However, existing models for seismic attenuation and velocity dispersion in fractured rocks neglect this complexity. In this work, we explore the effects of fracture contact areas on seismic P‐wave attenuation and velocity dispersion using oscillatory relaxation simulations based on quasi‐static poroelastic equations. We verify that the geometrical and mechanical details of fracture contact areas have a strong impact on seismic signatures. In addition, our numerical approach allows us to quantify the vertical solid displacement jump across fractures, the key quantity in the linear slip theory. We find that the displacement jump is strongly affected by the geometrical details of the fracture contact area and, due to the oscillatory fluid pressure diffusion process, is complex‐valued and frequency‐dependent. By using laboratory measurements of stress‐induced changes in the fracture contact area, we relate seismic attenuation and dispersion to the effective stress. The corresponding results do indeed indicate that seismic attenuation and phase velocity may constitute useful attributes to constrain the effective stress. Alternatively, knowledge of the effective stress may help to identify the regions in which wave induced fluid flow is expected to be the dominant attenuation mechanism.

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2014-09-09
2020-09-20
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References

  1. AdelinetM., FortinJ., GuéguenY., SchubnelA. and GeoffroyL., 2010. Frequency and fluid effects on elastic properties of basalts: Experimental investigations. Geophysical Research Letters37, L0203.
    [Google Scholar]
  2. BandisS., LumsdenA. and BartonN., 1983. Fundamentals of rock joint deformation. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts20, 249–268.
    [Google Scholar]
  3. BiotM. A., 1941. General theory of three‐dimensional consolidation. Journal of Applied Physics12, 155–164.
    [Google Scholar]
  4. BiotM. A., 1962. Mechanics of deformation and acoustic propagation in porous media. Journal of Applied Physics33, 1482–1498.
    [Google Scholar]
  5. BrajanovskiM., GurevichB. and SchoenbergM., 2005. A model for P‐wave attenuation and dispersion in a porous medium permeated by aligned fractures. Geophysical Journal International163, 372–384.
    [Google Scholar]
  6. BrajanovskiM., MüllerT. M. and GurevichB., 2006. Characteristic frequencies of seismic attenuation due to wave‐induced fluid flow in fractured porous media. Geophysical Journal International166, 574–578.
    [Google Scholar]
  7. ChapmanM., 2003. Frequency‐dependent anisotropy due to meso‐scale fractures in the presence of equant porosity. Geophysical Prospecting51, 369–379.
    [Google Scholar]
  8. ChapmanM., 2009. Modeling the effect of multiple sets of mesoscale fractures in porous rocks on frequency‐dependent anisotropy. Geophysics74, D97–D103.
    [Google Scholar]
  9. ClarkR. A., BensonP. M., CarterA. J. and Guerrero MorenoC. A., 2009. Anisotropic P‐wave attenuation measured from a multi‐azimuth surface seismic reflection survey. Geophysical Prospecting57, 835–845.
    [Google Scholar]
  10. GaleJ. F. W., LanderR. H., ReddR. M. and LaubachS. E., 2010. Modeling fracture porosity evolution in dolostone. Journal of Structural Geology32, 1201–1211.
    [Google Scholar]
  11. GoodmanR. E., 1976. Methods of Geological Engineering in Discontinuous Rocks, West Publishing, New York.
    [Google Scholar]
  12. GurevichB., BrajanovskiM., GalvinR. J., MüllerT. M. and Toms‐StewartJ., 2009. P‐wave dispersion and attenuation in fractured and porous reservoirs ‐ poroelasticity approach. Geophysical Prospecting57, 225–237.
    [Google Scholar]
  13. HopkinsD. L., CookN. G. W. and MyerL. R., 1987. Fracture stiffness and aperture as a function of applied stress and contact geometry. Rock Mechanics. Proceedings of the 28th US Symposium, Tucson, Arizona, pp. 673–680.
  14. HopkinsD. L., CookN. G. W. and MyerL. R., 1990. Normal joint stiffness as a function of spatial geometry and surface roughness. In Proceedings of the International Symposium on Rock Joints, Loen, Norway, pp. 203–210.
  15. HudsonJ. A., 1981. Wave speeds and attenuation of elastic waves in material containing cracks. Geophysical Journal of the Royal Astronomical Society64, 133–150.
    [Google Scholar]
  16. HudsonJ. A., LiuE. and CrampinS., 1996. The mechanical properties of materials with interconnected cracks and pores. Geophysical Journal International124, 105–112.
    [Google Scholar]
  17. HudsonJ. A., PointerT. and LiuE., 2001. Effective‐medium theories for fluid‐saturated materials with aligned cracks. Geophysical Prospecting49, 509–522.
    [Google Scholar]
  18. JaegerJ. C., CookN. G. W. and ZimmermanR. W., 2007. Fundamentals of rock mechanics. Fourth Edition. Blackwell Publishing.
    [Google Scholar]
  19. LiuE., HudsonJ. A. and PointerT., 2000. Equivalent medium representation of fractured rock. Journal of Geophysical Research105, 2981–3000.
    [Google Scholar]
  20. MaultzschS., ChapmanM., LiuE. and LiX. Y., 2003. Modelling frequency‐dependent seismic anisotropy in fluid‐saturated rock with aligned fractures: Implication of fracture size estimation from anisotropic measurements. Geophysical Prospecting51, 381–392.
    [Google Scholar]
  21. MavkoG. and NurA., 1975. Melt squirt in the asthenosphere. Journal of Geophysical Research80, 1444–1448.
    [Google Scholar]
  22. MavkoG., MukerjiT. and DvorkinJ., 1998. The rock physics handbook: Tools for seismic analysis in porous media. Cambridge University Press.
    [Google Scholar]
  23. MilaniM., RubinoJ. G., MüllerT. M., QuintalB. and HolligerK., 2014. Velocity and attenuation characteristics of P‐waves in periodically fractured media as inferred from numerical creep and relaxation tests. SEG Expanded Abstracts, 2882–2887.
  24. MüllerT. M. and RothertE., 2006. Seismic attenuation due to wave‐induced flow: Why Q in random structures scales differently. Geophysical Research Letters33, L16305.
    [Google Scholar]
  25. MüllerT. M., GurevichB. and LebedevM., 2010. Seismic wave attenuation and dispersion resulting from wave‐induced flow in porous rocks ‐ A review. Geophysics75, 75A147–75A164.
    [Google Scholar]
  26. MyerL. R., 2000. Fractures as collections of cracks. International Journal of Rock Mechanics and Mining Sciences37, 231–243.
    [Google Scholar]
  27. PayneS. S., WorthingtonM. H., OdlingN. E. and WestL. J., 2007. Estimating permeability from field measurements of seismic attenuation in fractured chalk. Geophysical Prospecting55, 643–653.
    [Google Scholar]
  28. PeacockS., McCannC., SothcottJ. and AstinT. R., 1994. Experimental measurements of seismic attenuation in microfractured sedimentary rock. Geophysics59, 1342–1351.
    [Google Scholar]
  29. Pyrak‐NolteL. J. and MorrisJ. P., 2000. Single fractures under normal stress: The relation between fracture specific stiffness and fluid flow. International Journal of Rock Mechanics and Mining37, 245–262.
    [Google Scholar]
  30. Pyrak‐NolteL. J., MyerL. R., CookN. G. W. and WitherspoonP., 1987. Hydraulic and mechanical properties of natural fractures in low‐permeability rock. Proceedings of 6th International Congress of Rock Mechanics, Montreal, pp. 225–231.
  31. Pyrak‐NolteL. J., MyerL. R. and CookN. G. W., 1990. Transmission of seismic waves across single natural fractures. Journal of Geophysical Research95, 8617–8638.
    [Google Scholar]
  32. RubinoJ. G., RavazzoliC. L. and SantosJ. E., 2009. Equivalent viscoelastic solids for heterogeneous fluid‐saturated porous rocks. Geophysics74, N1–N13.
    [Google Scholar]
  33. RubinoJ. G., GuarracinoL., MüllerT. M. and HolligerK., 2013a. Do seismic waves sense fracture connectivity?Geophysical Research Letters40, 692–696.
    [Google Scholar]
  34. RubinoJ. G., MonachesiL. B., MüllerT. M., GuarracinoL. and HolligerK., 2013b. Seismic wave attenuation and dispersion due to wave‐induced fluid flow in rocks with strong permeability fluctuations. Journal of the Acoustical Society of America134, 4742–4751.
    [Google Scholar]
  35. RubinoJ. G., MüllerT. M., GuarracinoL., MilaniM. and HolligerK., 2014. Seismoacoustic signatures of fracture connectivity. Journal of Geophysical Research119, 2252–2271.
    [Google Scholar]
  36. SayersC. M., 2007. Introduction to this special section: Fractures. The Leading Edge26, 1102–1105.
    [Google Scholar]
  37. SayersC. M., TaleghaniA. D. and AdachiJ., 2009. The effect of mineralization on the ratio of normal to tangential compliance of fractures. Geophysical Prospecting57, 439–446.
    [Google Scholar]
  38. SchoenbergM., 1980. Elastic wave behavior across linear slip interfaces. Journal of the Acoustical Society of America68, 1516–1521.
    [Google Scholar]
  39. VargheseA. V., ChapmanM. and HerwangerJ. V., 2009. Attenuation estimation in croswell data ‐ an indicator of fracture density and permeability?Extended Abstracts, EAGE.
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  • Article Type: Research Article
Keyword(s): Acoustics , Attenuation and Rock physics
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