A dip-dependent divergence correction
Abstract
A divergence correction is conventionally applied to zero-offset data in an effort to preserve amplitude information. The conventional divergence correction compensates for the geometrical spreading of a point source in a horizontally layered medium where velocity varies with depth only. The dip-dependent divergence correction extends the conventional correction for improved amplitude processing of dipping beds. The dip-dependent divergence correction is computed by dynamic ray tracing, and applied to stacked data using a dip decomposition technique. This correction decreases amplitudes relative to the conventional correction for steep dips and late times. In a data example from the Gulf of Mexico, the conventional correction over-amplified the reflection off a salt dome flank by a factor of 1.6. High amplitudes near salt flanks are also associated with the presence of hydrocarbons. Applying the dip-dependent divergence correction ensures that 'bright spots' are not due to over-amplification of steep dips by the conventional correction. In areas like the Gulf of Mexico, where the velocity function varies primarily with depth, and steep beds are commonplace, the dip-dependent divergence correction is an inexpensive way to improve the amplitude information in seismic images.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- September 1992
- Bibcode:
- 1992PhDT.........7F
- Keywords:
-
- Image Processing;
- Seismic Waves;
- Seismology;
- Correction;
- Divergence;
- Ray Tracing;
- Wave Propagation;
- Geophysics