Assessment of undiscovered resources on the Norwegian Continental Shelf

The Norwegian Petroleum Directorate (NPD) makes annual assessments of the total petroleum resources on the Norwegian Continental Shelf (NCS). Major updates of the undiscovered resources have been done every second year, most recently in 2003. The resource assessment provides an overview of the resource potential that can be materialized in the future. This is used by the government to plan future licensing rounds and to make forecasts on petroleum activity and it provides oil companies with valuable information about exploration potential. The NPD defines resources as the total recoverable petroleum. The estimation is done using a probabilistic method, using the mean value as the official number. The undiscovered resources are estimated as a total figure for both the mapped (prospects) and the unmapped (potential prospects) for each play. The input parameters are standard volumetric parameters, with the addition of distribution of prospect size, number of prospects likely to occur in a play and the average chance of success. Discoveries and prospects provide crucial information to the play analysis. The North Sea, although fairly mature, still holds a considerable potential of undiscovered resources and is assumed to be the most oil-rich province. Pre-Jurassic plays are poorly explored in the Norwegian sector, as are stratigraphic plays. A large part of the remaining resources is assumed to be in medium to small discoveries. The Norwegian Sea holds the largest potential of undiscovered resources, with potential large structural traps in Cretaceous and Tertiary deep-water plays in the Voring and More basins. The Barents Sea has potential for large discoveries of both oil and gas. Recent identification of pre-Jurassic source rocks increases the chance of discoveries in pre-Jurassic plays. The uncertainty in the estimates is large due to few wells drilled outside the Hammerfest Basin.