Revisiting PSDM Workflows Using Global Multi-scenario Traveltime Tomography

Prestack depth migration (PSDM) has become a standard technique for imaging sedimentary basins in many oil provinces. The classical velocity model building workflow is based on linearized traveltime tomography in the depth migrated domain. It has the drawback of being time consuming, since each tomographic update involves a full volume PSDM, and therefore allows only little flexibility in the velocity model building process. In this paper we propose a depth migrated domain formulation of non linear traveltime tomography. It allows in principle to build a velocity model from a single PSDM and opens up the way to new velocity model building workflows, that we will illustrate on a North Sea data example.