Macro Model Optimization and Depth-Migration

Any procedure to go from time to depth requires (among other features) a macro-model, i.e. a velocity model. This macro-model therefore has to be specified if one wants to apply any type of depth-migration, pre-or poststack. However, the same macro-model specification is needed if one wants to depth-convert an interpretation of e.g. a 2-D time section. The ever-lasting problem here was given by the question: how good is the final resulting depth map away from the fixpoints, i.e. wells, especially when the depthing is done by applying e.g. APPARENT VELOCITIES. In this work we describe the CONCEPT OF VELOCITY-CHECKiNG BY WAVEFRONTS which is applicable to both, i.e. conventional depthing problems as well as to depth-migration related problems, simply by using the given redundancy of normal seismic data.