A hybrid fuzzy-probabilistic system for risk analysis in petroleum exploration prospects

Petroleum exploration is an economical activity where many billions of dollars are invested every year. Despite these enormous investments, it is still considered a classical example of decision-making under uncertainty. In this paper, a new hybrid fuzzy-probabilistic methodology is proposed and the implementation of a software tool for assessing the risk of petroleum prospects is described. The methodology is based in a fuzzy-probabilistic representation of uncertain geological knowledge where the risk can be seen as a stochastic variable whose probability distribution counts on a codified geological argumentation. The risk of each geological factor is calculated as a fuzzy set through a fuzzy system and then associated with a probability interval. Then the risk of the whole prospect is calculated using simulation and fitted to a beta probability distribution. Finally, historical and direct hydrocarbon indicators data are incorporated in the model. The methodology is implemented in a prototype software tool called RCSUEX (“Certainty Representation of the Exploratory Success”). The results show that the method can be applied in systematizing the arguing and measuring the probability of success of a petroleum accumulation discovery.