Double Diffraction Stack For An Alternative Strategy For Crs-Based Limited-Aperture Kirchhoff Depth Migration

In Kirchhoff migration, the proper choice of the aperture is essential: the optimum aperture is the limited aperture defined by the first projected Fresnel zone. This is the smallest aperture providing interpretable amplitudes along with the highest possible S/N ratio and the minimum number of required summations. In addition, limited-aperture migration naturally prevents operator aliasing. The commonreflection-surface (CRS) stack provides kinematic wavefield attributes which allow to estimate the optimum aperture size for zero-offset and its dislocation with varying offset. The aperture is centered around the stationary point, but this point has to be associated with the corresponding point in the migrated domain in an additional process. Kirchhoff migration itself implicitly connects the stationary point and the image point in depth by collecting the energy in the vicinity of the former and assigning it to the latter. In principle, any smoothly varying property can be migrated “on top” of the seismic data themselves by applying multiple weighted diffraction stacks. The most generic property to be migrated in this way is the source/receiver midpoint which yields the lateral position of the stationary point mapped to the image location in depth. We investigate the validity and accuracy of this approach for simple<br>synthetic data and apply it to a real land data set. A straightforward extension is introduced to solve some of the numerical problems inherent to this approach and CRSbased strategies are transferred from the time domain to the depth domain to identify the reflector images and to attenuate migration noise. Finally, the approach is compared to another CRS-based approach which directly evaluates the tangency criterion.