Automatic event picking and tomography on 3D RTM angle gathers

Abstract

Automatic common image gather (CIG) event picking and tomography inversion are the main stream tools in velocity model building for prestack depth imaging projects. The conventional CIGs are typically in the offset domain, output from a ray based Kirchhoff migration. This kind of CIGs suffers from migration artifacts due to the multiarrival problem when the velocity model contains strong lateral variations. These artifacts cause difficulties in tomography. The CIGs in subsurface angle domain are, however, artifact‐free. With the help of wide azimuth acquisition and high performance computers, the 3D CIGs indexed by reflection angle and azimuth angle (ADCIGs) are now available within the output of reverse time migration (RTM). It brings new opportunities to observe the azimuthal dependent structural attributes and to refine subsurface model building. However, the automatic seismic event picking and tomography in angle domain face new challenges. In this abstract we address some implementation and application issues of automatic picking and tomography inversion on 3D angle domain CIGs. We have implemented our automatic picking and inversion tools for the 3D full azimuth ADCIGs. We demonstrate the efficiency and robustness of our algorithms using a Gulf of Mexico real data application.