As more resources are directed toward reverse time migration, an accurate velocity model, including strong reflectors, is necessary to form a clear image of the subsurface. This is of particular importance in the vicinity of salt, where singly scattered waves are often not ideal for imaging the salt flanks. This has led to interest in processing doubly scattered waves (also called duplex or prismatic waves) for imaging salt flanks and thus improving the location of salt boundaries in a velocity model. We used doubly scattered waves in a two-pass, one-way method to image salt flanks in a North Sea data set. By working in the one-way framework we were able to separately construct images with singly, doubly, and triply scattered waves. We used a multistep imaging process that includes multiply scattered waves by using an imaged reflector to fix one (or more) of the scattering points, allowing for multiply scattered energy from several reflectors, potentially with poor continuity, to be included without picking each reflector individually. With this method we were able to image the flank of a North Sea salt body.
Recursive imaging with multiply scattered waves using partial image regularization: A North Sea case study