Three-dimensional seismic angle migration and tomography

In this project we will associate the leading edge position of NTNU, represented by Bjørn Ursin, in the field of angle migration, with the high competence and experience of SINTEF with developing algorithms for 3D imaging in complicated geology In the f irst part of the project we plan to extend existing 2.5D programs to 3D pre-stack depth migration of PP reflections, both on marine streamer and OBC data. New imaging conditions (Ursin 2003) will be implemented and tested. The migrated output will be an e stimate of the reflection coefficient as function of scattering angle and azimuth.The methodology require 3D ray tracing in non-homogeneous media. The software will in parts be based on existing experience and software at SINTEF Petroleum Research. 3D to mographic velocity analysis will be developed in the second part of the project. Major geological boundaries will be estimated by map migration. The velocity function will be represented by a linear function with each major block plus a smooth part given by a 3D spline function, possibly B-splines. The P-wave velocity function will be estimated by minimizing a differential semblance function applied to angle-domain CIGs. These CIGs will be computed using the amplitude-compensated migration algorithm descr ibed in Ursin (2003).