Improved Ray-based Seismograms by Combining Modeling by Demigration with a Prestack Depth Migration Simulator

Ray-based seismic modeling methods can be applied at various stages of the exploration and production process, e.g., for comparison, simulation or representation of seismic data. Ray tracing in its standard forms is not always able to produce complete synthetic seismograms, as may be required for processing tests. Standard reflection-based modeling gives good results in many cases, but could fail for some complex structures. For instance, in the presence of sharp edges on the modeled reflector, or in the vicinity of caustics, classical dynamic ray tracing does not give reliable amplitude values. Therefore, we propose an alternative approach where we do not use reflection modeling. Instead we use an optimized ray-based approach to calculate Green's functions, e.g., amplitudes and traveltimes, which will be applied within tailored modeling schemes. Here, we adapt the original modeling by demigration approach using an alternative PSDM simulator. Even a simple two-layer model reveals the weaknesses of the standard ray tracing, and demonstrates on the contrary that the synthetic seismograms calculated with the presented method are more complete and significantly improved. Finally, we document the applicability of this approach using a reservoir model of the Norne Field (Norwegian continental shelf).