1887
Volume 36 Number 2
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

Numerical wavefield extrapolation represents the backbone of any algorithm for depth migration pre‐ or post‐stack. For such depth imaging techniques to yield reliable and interpretable results, the underlying wavefield extrapolation algorithm must propagate the waves through inhomogeneous media with a minimum of numerically induced distortion, over a range of frequencies and angles of propagation.

A review of finite‐difference (FD) approximations to the acoustic one‐way wave equation in the space‐frequency domain is presented. A straightforward generalization of the conventional FD formulation leads to an algorithm where the wavefield is continued downwards with space‐variant symmetric convolutional operators. The operators can be precomputed and made accessible in tables such that the ratio between the temporal frequency and the local velocity is used to determine the correct operator at each grid point during the downward continuation.

Convolutional operators are designed to fit the desired dispersion relation over a range of frequencies and angles of propagation such that the resulting numerical distortion is minimized. The optimization is constrained to ensure that evanescent energy and waves propagating at angles higher than the maximum design angle are attenuated in each extrapolation step. The resulting operators may be viewed as optimally truncated and bandlimited spatial versions of the familiar phase shift operator. They are unconditionally stable and can be applied explicitly. This results in a simple wave propagation algorithm, eminently suited for implementation on pipelined computers and on large parallel computing systems.

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2006-04-27
2024-04-19
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References

  1. Berkhout, A.J.1981. Wave field extrapolation techniques in seismic migration, a tutorial. Geophysics46, 1638–1656.
    [Google Scholar]
  2. Berkhout, A.J.1985. Seismic Migration. Imaging of acoustic energy by wavefield extrapolation. A. Theoretical aspects.Elsevier.
    [Google Scholar]
  3. Brillouin, L.1960. Wave Propagation and Group Velocity. Academic Press Inc.
    [Google Scholar]
  4. Claerbout, J.F.1971. Toward a unified theory of reflector mapping. Geophysics36, 467–481.
    [Google Scholar]
  5. Gazdag, J.1978. Wave equation migration with the phase‐shift method. Geophysics43, 1342–1351.
    [Google Scholar]
  6. Gazdag, J.1980. Wave equation migration with the accurate space derivative method. Geophysical Prospecting28, 60–70.
    [Google Scholar]
  7. Gazdag, J. and Sguazzero, P.1984. Interval velocity analysis by wave extrapolation. Geophysical Prospecting32, 454–479.
    [Google Scholar]
  8. Gazdag, J. and Sguazzero, P.1984. Migration of seismic data by phase shift plus interpolation. Geophyics49, 124–131.
    [Google Scholar]
  9. Hatton, L., Larner, K. and Gibson, B.S.1981. Migration of seismic data from inhomogeneous media. Geophysics46, 751–767.
    [Google Scholar]
  10. Holberg, O.1987. Computational aspects of the choice of operator and sampling interval for numerical differentiation in large‐scale simulation of wave phenomena. Geophysical Prospecting35, 629–655.
    [Google Scholar]
  11. Kosloff, D.D. and Baysal, E.1983. Migration with the full acoustic wave equation. Geophysics48, 677–687.
    [Google Scholar]
  12. Larner, K.L., Hatton, L., Gibson, B.S. and Hsu, I‐C.1981. Depth migration of imaged time sections. Geophysics46, 734–750.
    [Google Scholar]
  13. Loewenthal, L., Roberson, L.R. and Sherwood, J.1976. The wave equation applied to migration. Geophysical Prospecting24, 380–399.
    [Google Scholar]
  14. Moore, J.J., Garbow, B.S. and Hillstrøm, K.E.1980. User guide for Minpack‐1. Argonne National Laboratory ANL‐80–74.
    [Google Scholar]
  15. Schneider, W.A.1978. Integral formulation for migration in two and three dimensions. Geophysics43, 49–76.
    [Google Scholar]
  16. Schultz, P.S. and Sherwood, J.W.C.1980. Depth migration before stack. Geophysics45, 376–393.
    [Google Scholar]
  17. Trefethen, L.N.1982. Group velocity in finite difference schemes. Society of Industrial and Applied Mathematics Review24, 113–135.
    [Google Scholar]
  18. Ursin, B.1983. Review of elastic and electromagnetic wave propagation in horizontally layered media. Geophysics48, 1063–1081.
    [Google Scholar]
  19. Ursin, B.1984. Seismic migration using the WKB approximation. Geophysical Journal of the Royal Astronomical Society79, 339–352.
    [Google Scholar]
  20. Wapenaar, C.P.A. and Berkhout, A.J.1986. Wave field extrapolation techniques for inhomogeneous media which include critical angle events. Part II: Methods using the two‐way wave equation. Geophysical Prospecting34, 147–179.
    [Google Scholar]
  21. Wolfe, M.A.1978. Numerical Methods for Unconstrained Optimization. Van Nostrand Reinhold.
    [Google Scholar]
  22. Yilmaz, O. and Chambers, R.1984. Migration velocity analysis by wave‐field extrapolation. Geophysics49, 1664–1674.
    [Google Scholar]
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