Ray-based Tomography for Q Estimation and Q Compensation in Complex Media

In this paper, we discuss a ray-based tomographic approach to derive 3D Q models of the subsurface and the use of those models to perform model-driven Q compensation in complex media. The proposed approach is based on attenuated traveltime tomography applied on prestack surface seismic data and is integrated into a general ray-based post-migration grid tomography for both velocity and Q model building. Once a reliable space- and depth-variant Q model is derived, it can be used to perform Q compensation during depth migration. Alternatively, the Q model can be used to design Q compensation filters to apply outside migration. Such ray-based filters yield reliable amplitude and phase compensation even at medium or far offsets and allow us to mitigate absorption effects in the final depth-migrated images. The approach is illustrated using synthetic and real data.