RTM Imaging Conditions and Image Enhancement via Optical Stacking

Summary The final stage of a migration process is usually the imaging condition, which brings together elements of the upcoming and downgoing wavefields for each shot gather in order to form an image contribution. This procedure suffers limitations due to the approximations made in representing the physics of the system, but in addition to that, the final summation of all shot contributions necessarily assumes that the subsurface parameter model was perfect, such that all image contributions align perfectly for summation (within a Fresnel zone), as well as having recorded data that are noise free and adequately sampled. In this work, we assess the effect of unresolvable velocity errors on the final image, and present a case study example of a technique for compensating for these errors via techniques borrowed from astronomical image processing applied to each of each of the many thousands of elemental traces that contribute to the final image.