Anisotropic pre-stack depth migration of complex geological structures

M. Gratziella Kirtland Grech, P. F. Daley, Donald C. Lawton


An anisotropic pre-stack depth migration algorithm for P-P and P-S wave data has been developed and successfully tested on numerical and field data from the Rocky Mountain foothills of southern Alberta, Canada. The migration is diffraction stack type and uses an interface-based raytracer to compute traveltimes for traveltime table generation. When the exact migration-velocity model was known, the quality of the migrated image depended only on the robustness of the algorithm used to interpolate these ray-traced traveltimes onto a regular grid. Proper selection of the gridding routine resulted in smooth traveltime contours and good quality images that compare well with results obtained using industry standard production migration code.