f A New technique for 3D PreSDM model building - A North Sea case study

Here we present a North Sea case history of 3D pre-stack depth migration, where the velocitydepth model has been built iteratively using a new pre-stack velocity updating scheme. In order to assess improvement in image quality throughout the model building process, we analyse post-stack depth migration results, their corresponding pre-stack images, and image gathers for each iteration. In addition, in an attempt to assess the reliability of the models, we apply a 3D tomographic inversion technique to measure the consistency of the model at each iteration with observed travel times and stacking velocities.