Improving RTM images with angle gathers

Reverse time migration (RTM) can provide accurate subsurface images in the presence of large velocity variations and arbitrary geologic dip, and in current implementations can handle anisotropic effects up through at least tilted tranverse isotropy (TTI). It has become a standard migration tool for challenging imaging areas, such as subsalt Gulf of Mexico. Recent developments make it relatively easy to produce angle gathers for every point in image space. This provides opportunities for all manner of post migration, prestack processing to improve RTM results.