Diffractivity analysis of VSP data

Seismic diffractions are caused by small scale, but structurally important, details in the subsurface. It is thus profitable to isolate them from the full recorded wavefield and analyze them separately. This is particularly true for VSP data, because of the possibly strong diffraction content, due the close distance between downhole receivers and diffracting edges. The diffractivity depth section gives insight into the location of diffractors, and can serve as an additional tool for interpreters, as well as a starting point for further diffraction analysis. Diffractions can be filtered out from the full wav efield by a combined FK-rejection/medianenhancement filter. In the VSP case, the performance of the filter can be improved by selective muting of regions of tangency of reflected and diffracted events.