The slant-stack transform

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Seismic Data Analysis
Seismic-data-analysis.jpg
Series Investigations in Geophysics
Author Öz Yilmaz
DOI http://dx.doi.org/10.1190/1.9781560801580
ISBN ISBN 978-1-56080-094-1
Store SEG Online Store


In the 2-D Fourier transform, we learned that the 2-D Fourier transform is one way to decompose a wavefield into its plane-wave components, each with a unique frequency and each traveling at a unique angle from the vertical direction. In this section, we shall discuss the domain of ray parameter and present another way to decompose the wavefield into its plane-wave components.

Plane-wave decomposition of a wavefield, such as a common-shot gather, can be achieved by applying linear moveout and summing amplitudes over the offset axis. This procedure is called slant stacking. An underlying assumption of slant stacking is that of a horizontally layered earth model. Conventional processing is done primarily in midpoint-offset coordinates. Slant stacking replaces the offset axis with the ray parameter p axis. The ray parameter is the inverse of the horizontal phase velocity. A group of traces with a range of p values is called a slant-stack gather.

Several processing techniques have been devised, with varying degrees of success, in midpoint-ray-parameter coordinates. Examples include trace interpolation, multiple attenuation, time-variant dip filtering, refraction inversion, velocity analysis, migration before stack, and deconvolution. Taner [1] was the first to introduce the midpoint-ray-parameter coordinates. He discussed the interpretive use of plane-wave stacks, where several constant p sections are superpositioned over a restricted range of p values to enhance dipping events. Other processing methods were investigated later, such as migration [2] and velocity analysis [3] [4] and [5]. Alam and Lasocki [6] and Alam and Austin [7] discussed possible applications in trace interpolation and multiple attenuation, respectively. McMechan and Yedlin [8] devised a method to obtain phase velocity curves for dispersive waves using slant-stack transformation (Section F.1). Clayton and McMechan [9] devised a method to invert a refracted wavefield, which involves downward continuation in the slant-stack domain (Section F.2). Based on downward continuation of a slant-stack gather, Schultz (1982) developed a technique to estimate interval velocities.

References

  1. Taner (1977), Taner, M. T., 1977, Simplan — plane-wave stacking: Presented at the 37th Ann. Eur. Assoc. Explor. Geophys. Mtg.
  2. Ottolini, 1982, Ottolini, R., 1982, Migration of seismic data in angle-midpoint coordinates: Ph.D. thesis, Stanford University.
  3. Schultz and Claerbout, 1978, Schultz, P. S. and Claerbout, J. F., 1978, Velocity estimation by wavefront synthesis: Geophysics, 43, 691–712.
  4. Diebold and Stoffa, 1981, Diebold, J. B. and Stoffa, P. L., 1981, The traveltime equation, τ − p mapping and inversion of common midpoint data: Geophysics, 46, 238–254.
  5. Gonzalez-Serrano, 1982, Gonzalez-Serrano, A., 1982, Wave-equation velocity analysis: Ph.D. thesis, Stanford University.
  6. Alam and Lasocki (1981), Alam, A. and Lasocki, L., 1981, Slant stack and applications: Presented at the 41st Ann. Eur. Assoc. Expl. Geophys. Mtg.
  7. Alam and Austin (1981), Alam, A. and Austin, J., 1981, Multiple attenuation using slant stacks: Tech. Rep., Western Geophysical Company.
  8. McMechan and Yedlin (1981), McMechan, G. and Yedlin, M., 1981, Analysis of dispersive waves by wavefield transformation: Geophysics, 46, 869–879.
  9. Clayton and McMechan (1981), Clayton, R. W. and McMechan, G., 1981, Inversion of refraction data by wave-field extrapolation: Geophysics, 46, 860–868.

See also

External links

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The slant-stack transform
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