Angle-domain wave equation tomography using RTM image gathers

摘要

Wave equation tomography offers a way to better update the migration velocity model in the complex media. For real seismic data with finite frequency bandwidth, migration velocity updated from wave equation tomography is more suitable and robust for the advanced RTM. Meantime, RTM angle image gathers can provide nice moveouts with incorrect migration velocity for reliable velocity updating. In this paper, we present a wave equation tomography approach for velocity updating through the angle-domain sensitivity kernels. We propose a cost-effective way to calculate the angle domain sensitivity kernels. These angle-domain sensitivity kernels are used to convert the depth residuals from RTM angle image gathers into velocity perturbations, which are then used to refine the velocity model. We also propose a velocity model updating workflow in this paper. Examples from 2D sigsbee2 model and 3D SEAM model demonstrate the capability of this method for migration velocity updating.