Depth image focusing in traveltime map‐based wide‐angle migration

摘要: Wide‐aperture, prestack depth migration requires application of challenging and time‐consuming velocity analysis focusing, collectively referred to here as focusing. We present an approach focusing using (1) a detailed starting model obtained by 1‐D transformation the first‐arrival times, followed iteratively (2) interactive common‐image gathers, (3) computation coherency attributes wavefield in domain, (4) 2‐D traveltime tomography update background model. employ two method velocities refinement. In first (similar common‐midpoint spectrum approach), residual updates are picked directly from gathers. another (analogous common stacks), we pick areas maximum sections that migrated rescaled maps. Both types picks,...