Gaussian beam migration for anisotropic media

Gaussian beam migration (GBM), as it is implemented today, efficiently handles isotropic inhomogeneous media. The approach is based on the solution of the wave equation in ray-centered coordinates (s, n). The wave equation for anisotropic media in (s, n) coordinates is complicated and cumbersome to work with. An alternative that circumvents the complexity is to perturb the traveltimes in the GBM method. Although the perturbation technique is exemplified here for GBM, it just as well could be implemented for either Kirchhoff or slant stack migration. However, it is particularly cost efficient to use it for GBM; anisotropic GBM is slower than its isotropic counterpart by only 10%. The performance of this method is demonstrated on synthetic examples that show successful migration for reflector dips up to and beyond 90 degrees.