Costa, J. C., W. E. Medeiros, M. Schimmel, F. L. Santana, and J. Schleicher Reverse time migration using phase cross-correlation, GEOPHYSICS, 0(ja), 1-65, doi: 10.1190/geo2017-0791.1.
Abstract
Additional information regarding the continuity and resolution of selected seismic reflectors in Reverse Time Migration (RTM) images can be beneficial for seismic interpretation. We present and evaluate new imaging conditions for RTM based on the phase coherence between the forward and backward propagated wavefields. These imaging conditions make use of the instantaneous phase and envelope of the analytical signals of the source and receiver wavefields, in addition to their real parts. Once the analytical wavefields are available, these imaging conditions can be calculated simultaneously with conventional conditions at little or no extra cost. The availability of these fields at each image point enables several alternative ways to define imaging conditions. We explore, in addition to pure phase cross-correlation, two approaches of amplitude-weighted phase cross-correlation. Our numerical experiments, imaging both synthetic and field data sets, show that these new imaging conditions provide additional images that can highlight some weak reflectors by locally improving the resolution of RTM images. In our examples, this happens particularly in the deep portions of the seismic images. In addition, reflection events produced at discontinuities are enhanced as sharp signals, suggesting that the proposed imaging conditions can help to delineate both stratigraphic and structural features that are harder to see in conventional images. These properties of the phase cross-correlation imaging conditions make them an interesting tool to provide additional information that can aid seismic interpretation in complex structural settings.