Reverse-Time Migration - the Ultimate Subsalt Imaging Algorithm, but how about the Velocity Sensitivity?

Reverse-time migration (RTM) based on full two-way wave equation has gained interest and become a popular imaging tool for complex structures in the last few years. The method is well-known for its ability to better image the steeply dipping and overturn structures than the migration methods based on one-way wave equation extrapolation. Here, we implemented the RTM algorithm via a high-order finite differencing, and tested the algorithm on both synthetic and field datasets. In addition, we compared the resultant images with those generated via PSPI (phase-shift-plus-interpolation) migration, a one-way extrapolation method. The comparison demonstrates that RTM can be used to enhance the imaging quality, especially for steeply dipping and overturn structures, but RTM is more sensitive to velocity model than PSPI migration.