Converted wave (PS) analysis provides valuable information for subsurface characterization. It can provide information about lithology, fluid content, pore pressure, subsurface stresses and can play an important role in reservoir monitoring. Shear-wave velocity (Vs) model building from PS data involves challenges of event registration of both the compressional wave (PP) and converted-wave (PS) data. Additionally, current deep-water ocean-bottom node acquisitions present challenges in processing converted waves due to the sparsity of the receivers optimized for PP imaging.
Presented here is a case study where we developed a workflow to build a background S-wave velocity model for an existing deep-water ocean-bottom node (OBN) survey in the Gulf of Mexico.