Stacking Velocity Analysis with Model-based Common-Diffraction-Surface (CDS) Stack Attributes

Velocity analysis is an important part of seismic data processing steps. The stacking velocity can be calculated by the Normal-Incident-Point (NIP) wave and the emergence angle, which are attributes of Common-Reflection-Surface (CRS) stack method. But the NIP-wave is impressed by the Normal wave of the CRS attribute. The Common-Diffraction-Surface (CDS) stack is introduced by developing the CRS method. The model-based CDS attributes can be calculated by ray tracing on smooth velocity model with minor accuracy. As in model-based CDS method, the NIP-wave is not affected by N-wave. Hence, the calculated stacking velocity is more accurate and more reliable. Here, it is proposed by us to apply the model-based CDS on a range of constant velocity model several times. In this way, the coherence and stacking velocity sections are produced for each time. In addition, the production of coherence and stacking velocity sections allows us to select the stacking velocity with high coherence. Finally, the propose method on a synthetic model with five layers has been applied and the results of stacking velocity obtained by CRS have been compared with the results obtained from model-based CDS method. The results show a great improvement in accuracy of stacking velocity calculated with CDS attributes.