CRS Stacking Velocity Estimation - A Key to High-Resolution Seismic

The seismic line considered in this case study is a typical example of land data from an arid region. Strong variations of the surface conditions from deep weathering zones to outcrops of consolidated rocks were posing the main problem, and imaging quality primarily depended on the compensation for the surface effects. Static corrections, however, could not completely remove the surface-induced imaging problems. In areas with strong near-surface inhomogeneities, e.g. below deep bottom fills of a wadi, the resolution and event continuity still were much lower than in undisturbed areas. These remaining problems due to near-surface inhomogeneities, however, could be solved by appropriate dynamic corrections that are obtained from CRS processing. The local adaptation of CRS imaging parameters at every point of the image automatically provides very detailed dynamic corrections. These corrections produce a major increase of signal frequency and event continuity, and widely adapt the signal quality in disturbed areas towards the undisturbed signal character. It turns out that the strong surface inhomogeneities induce small-scale variations of the stacking velocities in the subsurface below, that cannot be resolved by manual velocity analysis and by the resulting smooth velocity field.