The velocity models were provided by Chevron. I start with these velocity models. I first handle the PP section, perform Stolt residual migration on this section only and update the velocity model with a selection of combined values of . After the P velocity model is updated, I perform the PS migration and residual migration; however, I do not scan over values. I scan only over and values.
The velocities vary both horizontally
and vertically. Therefore, there will not be a single set of parameters
to correct the entire section. The value will be
choosen
at Alba's depth at the center of the section.