CRS strategies for solving severe static and imaging issues in seismic data from Saudi Arabia
G. Gierse, J. Pruessmann and R. Coman
Journal name: Geophysical Prospecting
Issue: Vol 54, No 6, November 2006 pp. 709 - 719
Special topic: Section I – Madrid Workshop on Near-Surface 2005
Info: Article, PDF ( 1.26Mb )
Static shifts from near-surface inhomogeneities very often represent the key problem in the processing of seismic data from arid regions. In this case study, the deep bottom fill of a wadi strongly degrades the image quality of a 2D seismic data set. The resulting static and dynamic problems are solved by both conventional and common-reflection-surface (CRS) processing. A straightforward approach derives conventional refraction statics from picked first breaks and then goes through several iterations of manual velocity picking and residual statics calculation. The surface-induced static and dynamic inhomogeneities, however, are not completely solved by these conventional methods.
In CRS processing, the local adaptation of the CRS stacking parameters results in very detailed dynamic corrections. They resolve the local inhomogeneities that were not detected by manual picking of stacking velocities and largely compensate for the surface-induced deterioration in the stack. The subsequent CRS residual statics calculations benefit greatly from the large CRS stacking fold which increases the numbers of estimates for single static shifts. This improves the surface-consistent averaging of static shifts and the convergence of the static solution which removes the remaining static shifts in the 2D seismic data. The large CRS stacking fold also increases the signal-to-noise ratio in the final CRS stack.