Non-linear Slope Tomography for Orthorhombic Pre-stack Time Imaging

In the context of WAZ data the VTI hypothesis is not always sufficient for insuring focusing of time migration. We propose an extension of non-linear slope tomography for time imaging to the orthorhombic case. We use a model of orthorhombic anisotropy parameterized by five effective parameters and where the effective velocity and eta vary according to the azimuth of the migrated trace. In our approach the five parameters are updated jointly, allowing extending to the orthorhombic case the advantages of non-linear slope tomography for time velocity model building, i.e. and improved accuracy and turn-around.