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.