Reverse time migration of internal multiples

Abstract

Internal multiple reflections have different propagation paths compared with primary reflections and surface-related multiples, thus can complement illuminations where other waves are unavailable. We propose a novel approach to image structures with internal multiples. With this method, internal multiples are separated and used as data for reverse time migration. Instead of applying image condition directly to the source and receiver waves, we decompose both source and receiver waves extrapolated into upand down-going waves. Then apply the image condition to up-going source and receiver waves to form an up-up image, and apply to down-going source and receiver waves to form a downdown image. The image from the true reflector and the artifact show different features in the down-down and up-up images. We use a similarity analysis to compare the up-up and down-down images, and separate true images from artifacts. Numerical examples with simple velocity models are used to demonstrate how to construct up-up and downdown image conditions and eliminate migration artifacts. Finally, we test the 2D SMAART JV model with salt structures for migration using internal multiples.