That all depends on whether you want the probability of no oil...

That all depends on whether you want the probability of no oil or the probability of no economically producable oil. The first will be hard on Nido, the second will result in an announcement of shows / logged oil, maybe even some being recovered by MDT, which will have an impact on share price short term, but may result in the same long term effect as no oil whatsoever.

as for the previous question, there is a big difference between oil in place, which is quoted and recoverable oil, especially in these limestone plays, then you have to ask how the risk or POS is defined before you can use it to derive potential values