Enhancing Play Assessment Accuracy within the Halten Terrace Jurassic Petroleum System Using Discovery Process Modeling

A Bayesian version of the discovery process model was applied to the pre-rift Lower and Middle Jurassic play of the Halten Terrace Petroleum System, Mid-Norway. The Bayesian approach estimates the lognormal parameters, the discoverability parameter, and the distribution of sizes of the undiscovered fields as well as the play potential, conditioned on a discovery sequence. This process may be constrained by judgemental evidence derived from the Petroleum System expressed as permissible regions for the parent population parameters and the sizes of the expected largest and smallest remaining discoveries. The estimates of parameters and play potential based upon the present methodology compares well with current estimates, if the play is divided into two sub-plays representing the overpressured and normally pressured zones. These sub-plays should be estimated independently and aggregated in order to get the total undiscovered resource potential. Geological conditioning through the study of the petroleum system and the particularities of individual exploration plays integrated with the discovery sequence within a Bayesian framework may be significantly more accurate than methods using non-constrained extrapolation of creaming curves. KEY WORDS: Bayesian estimation, discovery process modeling, evaluation of petroleum resources, Halten terrace