Migration of surface correlated multiples based on one-way wave equation

Abstract

In conventional seismic data processing, multiple reflection waves are regarded as noise which should be removed from seismic data in order to avoid misunderstanding. In fact, multiples are also signals which contribute to part of subsurface structure illumination and imaging. In this paper, we analyzed the artifact generating mechanism and phenomenon caused by multiples in conventional one-way equation based pre-stack depth migration. In order to realize multiple imaging based on one-way wave equation, the boundary condition of one-way wave-equation based pre-stack depth migration was modified. It means that the input source wave field and recorded wave field are replaced by the record containing multiples and predicted surface correlated multiples, respectively. Then we stacked the pre-stack depth migration results from primaries and multiples based on the matching operator which is obtained from the norm II least-square energy difference methods. Imaging with multiples is a good compensation to imaging to that with primaries. The test on a simple model shows the validity of our method. Finally, jointed imaging with primaries and multiples was performed on the Sigsbee2B model. The results show that the imaging of the steep salt boundary was improved dramatically.