I think the key concept is the oil charge.Oil is generated...

I think the key concept is the oil charge.

Oil is generated first, as the deeper source rock is buried and reaches organic maturity. So the Rafael structure would have first filled up with oil.

As the source rock gets buried deeper it goes into that gas generation phase. This gas migrates into the trap and eventually displaces the oil - like farting in the tub.

So then the question is how much is displaced.

One extreme is all the oil is displaced then migrates up dip to the next trap - So Rafael is all gas and Shallow all oil.

The other outcome is only some displaced so get some oil at Shallow and a residual oil leg at Rafael.

Impossible to predict until you drill it.

Based on this the real risk is - do you have a migration pathway and a valid trap when the migration occured?

But can realistically see a model with early trap, good fault seal, high porosity reservoir.

Combine this with secondary migration from Rafael and you have a scenario for a large light oil combination.

A bit like the Cooper basin with deep gas and oil in the overlying Eromanga basin - prolific play