Dip Constrained Tomography as Applied to Subsalt North Sea Data

Developed for the shallow channel anomalies in the North Sea, the dip constrained tomography can also be effective in subsalt areas, when geological dip constraints are known. Subsalt areas often suffer from noisy residual move-out information and limited angular coverage. In this work, we show that the introduction in the non-linear slope-tomography cost function of an additional term related to the offset-dependent imaged dips helps in stabilizing the inversion and the computed velocity perturbations. We use a North Sea example to demonstrate that the use of geological constraints in this extended tomography below complex overburdens improves the seismic image focusing and provides a more geologically plausible velocity model.