Dip-moveout correction

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Seismic Data Analysis
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


The normal-moveout correction in Figure 1.5-14 was applied to the CMP gathers using the velocity field of Figure 1.5-12 that is optimum for flat events. Stacking velocities, however, are dip-dependent. Dip-moveout correction (DMO) is needed to correct for the dip effect on stacking velocities and thus preserve events with conflicting dips during CMP stacking. Dip-moveout correction has been an integral part of a conventional processing sequence for 2-D and 3-D seismic data since 1985.

  • Figure 1.5-12  Velocity field over the length of the seismic line under consideration. This isovelocity contour map was derived using the velocity picks from the spectra in Figure 1.5-11.
    Figure 1.5-12  Velocity field over the length of the seismic line under consideration. This isovelocity contour map was derived using the velocity picks from the spectra in Figure 1.5-11.
  • Figure 1.5-14  The CMP gathers as in Figure 1.5-13 after muting to remove frequency distortion at shallow portions and large offsets resulting from moveout correction.
    Figure 1.5-14  The CMP gathers as in Figure 1.5-13 after muting to remove frequency distortion at shallow portions and large offsets resulting from moveout correction.

Dip-moveout correction is applied to data following the normal-moveout correction using flat-event velocities (Figure 1.5-15). This then is followed by inverse moveout correction (Figure 1.5-16) and subsequent velocity analysis at closely spaced intervals. Figure 1.5-17 shows the velocity spectra associated with a subset of the analysis locations which correspond to those of Figure 1.5-11. As for the velocity spectra in Figure 1.5-11, the velocity range is 1000-5000 m/s and the maximum time is 8 s. Also, red indicates the maximum coherency measure.

  • Figure 1.5-11  Velocity spectra derived from the CMP gathers as in Figure 1.5-9.
    Figure 1.5-11  Velocity spectra derived from the CMP gathers as in Figure 1.5-9.
  • Figure 1.5-15  The CMP gathers as in Figure 1.5-14 after dip-moveout (DMO) correction.
    Figure 1.5-15  The CMP gathers as in Figure 1.5-14 after dip-moveout (DMO) correction.
  • Figure 1.5-16  The CMP gathers as in Figure 1.5-15 after inverse moveout correction using the velocity field in Figure 1.5-12.
    Figure 1.5-16  The CMP gathers as in Figure 1.5-15 after inverse moveout correction using the velocity field in Figure 1.5-12.
  • Figure 1.5-17  Velocity spectra derived from NMO- and DMO-corrected gathers as in Figure 1.5-16.
    Figure 1.5-17  Velocity spectra derived from NMO- and DMO-corrected gathers as in Figure 1.5-16.

See also

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Dip-moveout correction
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