Practical Aspects of Subsalt Tomography Using Reverse Time Migration Based Angle Gathers

Due to the accuracy of the Reverse Time Migration (RTM) algorithm, RTM angle gathers show more coherent and correct moveout subsalt events than Kirchhoff offset gathers, potentially providing a more reliable input for tomography. We have developed a robust, efficient, RTM angle gather generation method. It has the flexibility to incorporate geological knowledge for low signal-to-noise (S/N) areas. Because angle gather tomography targets subsalt areas, it is not necessary to trace rays through salt, thus avoiding the limitations of ray-based tomography, making it a useful tool for subsalt velocity model building.