1887
Volume 57, Issue 3
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

The effect of a fracture on the propagation of seismic waves can be represented in terms of the normal compliance and tangential compliance of the fracture. If /= 1 for all fractures, the effective elastic stiffness tensor of an isotropic background containing an arbitrary orientation distribution of fractures is orthotropic (i.e., has three orthogonal planes of mirror symmetry) in the long‐wave limit. However, deviations from orthotropy may occur if / differs significantly from unity and this can cause the principal axes of the ‐wave NMO ellipse and of the variation in the ‐reflection amplitude as a function of azimuth, to deviate from the fast and slow polarization direction of a vertically propagating ‐wave. Simple models of a fracture in terms of a planar distribution of cracks suggest that /≈ 1 for dry fractures. However, naturally occurring fractures often exhibit mineralization in the form of bridges between opposing faces of the fracture. The presence of such bridges leads to significant departures of / from unity.

Loading

Article metrics loading...

/content/journals/10.1111/j.1365-2478.2008.00746.x
2008-10-17
2024-04-23
Loading full text...

Full text loading...

References

  1. BaikJ.M. and ThompsonR.B.1984. Ultrasonic scattering from imperfect interfaces. Journal of Nondestructive Evaluation4, 177–197.
    [Google Scholar]
  2. EshelbyJ.D.1961. Elastic inclusions and inhomogeneities. In: Progress in Solid Mechanics , Vol. II (ed. I.N.Sneddon and R.Hill ), pp. 89–140. North‐Holland .
    [Google Scholar]
  3. JonesJ.P. and WhittierJ.S.1967. Waves at a flexibly bonded interface. Journal of Applied Mechanics34, 905–909.
    [Google Scholar]
  4. KachanovM.1980. Continuum model of medium with cracks. Journal of the Engineering Mechanics Division of the American Society of Civil Engineers106, 1039–1051.
    [Google Scholar]
  5. LaubachS.E.2003. Practical approaches to identifying sealed and open fractures. Bulletin of the American Association of Petroleum Geologists87, 561–579.
    [Google Scholar]
  6. LaubachS.E., ReedR.M., OlsonJ.E., LanderR.H. and BonnellL.M.2004. Coevolution of crack‐seal texture and fracture porosity in sedimentary rocks: cathodoluminescence observations of regional fractures. Journal of Structural Geology26, 967–982.
    [Google Scholar]
  7. LaubachS.E. and WardM.E.2006. Diagenesis in porosity evolution of opening‐mode fractures, Middle Triassic to Lower Jurassic La Boca Formation, NE Mexico. Tectonophysics419, 75–97.
    [Google Scholar]
  8. MargetanF.J., ThomsenR.B. and GrayT.A.1988. Interfacial spring model for ultrasonic interactions with imperfect interfaces: theory of oblique incidence and application to diffusion‐bonded joints. Journal of Nondestructive Evaluation7, 131–152.
    [Google Scholar]
  9. NagyP.B.1992. Ultrasonic classification of imperfect interfaces. Journal of Nondestructive Evaluation11, 127–139.
    [Google Scholar]
  10. NelsonR.A.1985. Geologic Analysis of Naturally Fractured Reservoirs . Gulf Professional Publishing. ISBN 0884153177.
    [Google Scholar]
  11. ReissL.H.1980. The Reservoir Engineering Aspects of Fractured Formations . Editions Technip. ISBN 2710803747.
    [Google Scholar]
  12. SayersC.M.1998. Misalignment of the orientation of fractures and the principal axes for P‐ and S‐waves in rocks containing multiple non‐orthogonal fracture sets. Geophysical Journal International133, 459–466.
    [Google Scholar]
  13. SayersC.M. and DeanS.2001. Azimuth‐dependent AVO in reservoirs containing non‐orthogonal fracture sets. Geophysical Prospecting49, 100–106.
    [Google Scholar]
  14. SayersC.M. and KachanovM.1991. A simple technique for finding effective elastic constants of cracked solids for arbitrary crack orientation statistics. International Journal of Solids and Structures12, 81–97.
    [Google Scholar]
  15. SayersC.M. and KachanovM.1995. Microcrack‐induced elastic wave anisotropy of brittle rocks. Journal of Geophysical Research B100, 4149–4156.
    [Google Scholar]
  16. SchoenbergM.1980. Elastic wave behavior across linear slip interfaces. Journal of the Acoustical Society of America68, 1516–1521.
    [Google Scholar]
  17. TadaH., ParisP.C. and IrwinG.R.1973. The Stress Analysis of Cracks Handbook , 2nd edn. Paris Productions Inc.
    [Google Scholar]
  18. YoshiokaN. and ScholzC.H.1989a. Elastic properties of contacting surfaces under normal and shear loads: 1. Theory. Journal of Geophysical Research B94, 17681–17690.
    [Google Scholar]
  19. YoshiokaN. and ScholzC.H.1989b. Elastic properties of contacting surfaces under normal and shear loads: 2. Comparison of theory with experiment. Journal of Geophysical Research B94, 17691–17700.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/j.1365-2478.2008.00746.x
Loading
/content/journals/10.1111/j.1365-2478.2008.00746.x
Loading

Data & Media loading...

  • Article Type: Research Article

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error