Improved Resolution of Slant Stacks Using Beam Stacks
, by Clement Kostov and Biondo Biondi
The separation of reflected waves by local slant stacks
is adversely affected by the spatial variability and the
curvature of the wavefront. The resolution of local slant stacks can be improved by replacing the straight line stacking trajectories
of local slant stacks with segments of hyperbolic trajectories.
In a common-midpoint (CMP) gather a unique traveltime curve is determined given a dip, an arrival time and a receiver position.
The derivation of this result assumes vertically stratified velocity
and planar reflectors, but makes otherwise no reference
to a specific velocity function.
Knowledge of the expected traveltime curve allows an alternative stacking method, that takes into account the curvature of the wavefront. Field data examples show the improvements in resolution gained using the new stacking method in the following applications:
first beamforming, that is selection of energy propagating in a specific direction, and second the design of anti-aliasing weights for a conventional global slant stack of a CMP gather.