| Angle-domain common-image gathers (ADCIGs) of 2D common-source seismic data are the result of prestack migration followed by selection of the migrated traces corresponding to one common image position, as a function of incident or reflected angle. When using the cross-correlation image condition in 2D prestack migration, the usual practice is to sum the over all the migration time steps so the result is a singlemigrated image for each source; this automatically includes all primary and multipath contributions, as well as those from multiples. However, if the image time slices within a cross-correlation common-source migration are saved for each image time, this three-parameter (incident angle, depth, image time) volume can be postprocessed to generate separate, or composite, images by selecting (or removing) any desired subset of the migrated data using those three data dimensions. Thus, separate images can be displayed for the primary (first or largest) contributions, any combination of different contributions. |
