KINEMATIC REDATUMING BY KIRCHHOFF SUMMATION
Seismic, Kirchhoff Migration, Redatuming
When land seismic data acquisition must account for the influence of a rugged topography and considerable velocity inhomogeneity (like a thick weathering layer) below the measurement surface, the various static correction methods usually provide incorrect temporal adjustments and thus incoherent sub-optimal stacks. The reason is that the time corrections are based on vertical ray trajectories between the measurement surface and the base of the weathering layer. They thus disregard lateral variations of the ray path. It is for this reason that we propose a geometric kinematic redatuming method that does not suffer from this problem. It results from cascading a Kirchhoff migration and demigration.
In view of the difficulties in the treatment of amplitudes on land data, we perform only kinematic (unweighted) stacks. This is enough to produce convincing results to justify the deployment of all usual pre- and poststack-processes and ultimately create seismic images which are consistent with the geology in question.