Risking a prospect with a DHI
If you assess the geological Chance of Success of a prospect (reservoir, seal, source etc), and then you get some additional information from a DHI which is also uncertain, how should you update your geological risk estimate? A simple gut-feel approach to modifying your prospect risk is likely to be prone to error. A logical approach is to use Bayes Theorem to combine the two sets of uncertain data.
However Bayes Theorem can be difficult to a apply because the uncertainty of the DHI has to be expressed in terms of False Positives and False Negatives. That is, what proportion of DHIs like this one are caused by something other than the fluid that you are searching for? And what proportion of prospects like this one will have the desired fluid but not show a DHI?
Bayes theorem can lead an explorationist into strange territory. A good DHI plus Bayes can do wonders for your prospect’s Chance of Success. An unfortunate corollary is that if your prospect does not show a DHI when it should, do you have the courage to use Bayes to downgrade the Chance of Success?