Prediction of oil or gas pool sizes when discovery record is available

The Upper Devonian Bashaw reef play of the Western Canada Basin was used to demonstrate: (1) estimation of pool size distribution by means of a discovery model, (2) the usefulness of a feedback mechanism in petroleum resources evaluations, and (3) enhancement of reliability by reducing uncertainty associated with estimates. The feedback mechanism presented herein allows us to challenge geological interpretations. For example, given the second largest pool size, the largest pool size can be estimated, and vice versa. In evaluations of petroleum resources, the uncertainty inherited from superpopulations is inevitably associated with the estimates. This type of uncertainty can be reduced to a certain extent if additional information is included in the estimation procedures and, consequently, the reliability of the estimates is enhanced. The additional information used may, for example, be the geological interpretation of a particular play. To achieve maximum effectiveness, resource evaluation methods should possess these types of flexibility. This study also estimated, with a 90% probability, that the remaining potential in the Bashaw reef play ranges from 32 to 50 millions of cubic meters (200 to 300 MM bbl) of oil in place.