Page 515 - Acquisition and Processing of Marine Seismic Data

506 11. SEISMIC MIGRATION

FIG. 11.14 The effect of migration aperture on the output of a poststack Kirchhoff time migration. Unnecessarily small
apertures cause loss of steeply dipping events, such as the flanks of the diapiric structure at the center.

11.2.2 Maximum Dip Restriction
Fig. 11.15C. In conclusion, small apertures cause
suppression of steeply dipping events and The maximum dip desired in the migration
results in fake subhorizontal events, especially output can be defined during the Kirchhoff
in the deeper parts of the section. In addition, migration process, which can be used to sup-
an unnecessarily large aperture significantly press steeply dipping coherent noise. Restriction
increases the computational time of the migra- of the dip is a method to reduce the run time of
tion and may degrade the output image quality the migration, since the dip parameter is related
in the shallower region of the data, when the to the migration aperture. The smaller the max-
S/N ratio of the input is low. imum allowed dip, the narrower the migration