Prestack migration/imaging using synthetic beam sources and plane sources

The principle and procedures of beam-source and plane-source synthesis for wave-equation based imaging/migration are introduced and tested with Gabor-Daubechies and local-cosine beamlet prestack migration. Plane-source synthesis and imaging are treated as a special case of approximation to the beam-source synthesis and imaging. Beam sources with properly selected windows provide both space and direction localizations for illumination and are very flexible for target-oriented migration using wave-theory based methods. On the other hand, plane-source imaging can increase the computation efficiency of depth migration significantly, up to 5-10 times for the SEG-EAGE 2D salt model and Marmousi model, while maintains the image quality similar or comparable to that of point-source (common-shot) imaging/migration.