RE: Probability20 Jan 2021 18:38
90% chance of oil reservoir does not mean 90% chance of oil. It means there is a 90% that BPC find reservoir sands that are of adequate quality (porosity and permeability) to hold and ultimately discharge/produce oil (whether those sands hold oil or not).
Four things need to happen: oil needs to be produced in the kitchen, find a migration path to the target, find suitable reservoir to saturate, and be kept in the reservoir by a trap (impermeable seal).
There is a 70% chance oil is generated locally. Then 52.5% chance generated oil migrated to the target (0.7x0.75). You could say that is the chance of the drill seeing oil, but it could be meaningful or it could just be traces of oil that passed through, depending on the next two risks.
The chance of oil reaching the location and being trapped there is 39% (0.525 x 0.75). And the chance that it got trapped there in suitable sand to hold and now give-up meaningful quantities is 0.9 x 39% = 35%.