A comparison of shot-encoding schemes for wave-equation migration

The seismic imaging industry is increasingly collecting data volumes with a substantial amount of redundancy through acquisition geometries including: wide-azimuth, rich-azimuth and full-azimuth. The increased redundancy improves image quality in areas with complex geology, but requires greater computational power to construct an image because of the additional data. One way to reduce the computational cost is to blend shotrecords, together prior to imaging which reduces the number of migrations necessary for imaging. The downside to doing so is that blending introduces strong, nonphysical, cross-talk noise into the final image. However, the crosstalk can be attenuated by carefully selecting a shot-encoding scheme. Many shot-encoding schemes have been proposed, but have not been directly compared to one another which makes it difficult to understand the relative advantages of the different schemes. We compare a few prominent shot-encoding schemes in a common theoretical framework and on a common dataset. Overall, we find that no single shotencoding scheme is always better than others, and that decimated shot-record migration is advantageous over blended imaging.