Imaging With Secondary Scattered Waves

From the point of view of wave propagation and time-reverse back propagation, multiples and secondary scattered waves, which are usually abandoned or treated as noises during traditional one-way wave- equation-based migration and imaging, can contribute to the final image if they are properly handled during migration and imaging. We propose an approach to migration and imaging with secondary scattered waves. Secondary scattered waves are extracted by a back propagation plus cross-correlation approach. The surface shot gathers are thus redatumed to subsurface shot gathers with sources located at some subsurface scatterers (gathers of scattering sources). Numerical examples confirm the validity of this Green's function retrieval approach. Migration and imaging from these redatumed shot gathers improves the final image. The proposed approach has a potential application to migration and imaging in 'shadow zones' of primaries such as in some subsalt region.