Selecting an optimal aperture in Kirchhoff migration using dip-angle images

Conclusions

Migration-aperture optimization in Kirchhoff angle-domain migration can significantly enhance the quality of a seismic image. The aperture-optimization method needs to eliminate migration artifacts without distorting the useful signal. The diffraction component of the seismic wavefield characterizes small but important geological objects and brings extra resolution to seismic imaging. For an optimal image of diffraction objects, as wide a migration aperture as possible should be used. However, imaging of reflections requires an aperture narrowed around the tangent point.

To meet both requirements, we propose utilizing constant-dip partial images. An analysis of the consistency between local slopes and constant dips of a partial image makes evaluating the contribution of any part of the migrated data possible. This analysis allows us to extract constructive events. Stacking these events is equivalent to migration using an optimal aperture.