Aspects of DMO correction — a summary

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Seismic Data Analysis
Series Investigations in Geophysics
Author Öz Yilmaz
ISBN ISBN 978-1-56080-094-1
Store SEG Online Store

We discussed the principles of DMO correction and studied its practical aspects using synthetic and field data. It now is appropriate to compile aspects of DMO correction.

  1. The process of dip-moveout corrects for the dip effect on stacking velocities.
  2. Thus, it preserves conflicting dips with different stacking velocities during CMP stacking.
  3. The DMO stack, therefore, is a closer representation of a zero-offset section as compared to a conventional CMP stack based on normal-moveout correction, only.
  4. The DMO stack can then be migrated using a zero-offset migration algorithm with greater accuracy.
  5. Conflicting dips with different stacking velocities give rise to multivalued velocity picks from velocity spectra. Velocity analysis of DMO-corrected data alleviates this problem and increases the accuracy of picking an unambiguous velocity function from a velocity spectrum.
  6. Velocities estimated from DMO-corrected data are dip independent; therefore, they are more suitable to derive a migration velocity field as compared to velocities estimated from data without DMO correction.
  7. Dip-moveout correction actually is a process of partial migration before stack. Specifically, it maps normal-moveout-corrected data to normal-incidence reflection points in the subsurface. As a result, midpoint coordinate is variant under DMO correction.
  8. As a direct consequence of aspect (g), DMO correction removes the reflection point dispersal associated with nonzero-offset recording in the presence of dipping reflectors.
  9. Following DMO correction, prestack data can be migrated so as to create CMP gathers in their migrated position. This then enables us to conduct velocity analysis to derive a migration velocity field with greater confidence.
  10. Finally, the CMP gathers from prestack time migration of DMO-corrected data can be used for amplitude variation with offset analysis.

In this chapter, we discussed the dip-moveout process within the context of 2-D seismic data. Three-dimensional aspects of DMO correction are discussed in processing of 3-D seismic data.

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Aspects of DMO correction — a summary
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