Welcome on board. Agree with your numbers on the shallow wells. Payback is in the order of 90 days.
Interesting reflecting on this in the context of the intermediate wells. I have heard talk of potentially 1500bopd from the intermediate wells. Seems reasonable given the increased overburden pressure and the fact that these fields fall in the 50-150mbo range. Obviously POS% will have an impact on payback times, but if you consider that some of these intermediate fields are at relatively shallow levels (circa 1200m) and will be drilled therefore at considerably less than the anticipated average of $2.5m per well, you might get paybacks that are better again!
Incidentally, some of these fields are so shallow that we may even be in a position to drill them with the shallow rig.