Carbon isotopic studies of kerogen assemblages and petroleums from the North Slope-Colville trough area of Alaska have permitted firmer source-oil correlation assignments. As a section, the Mesozoic contains a suite of potential source beds including the Shublik Formation, Kingak Shale formation, and Lower Cretaceous units and, most notably, a post-Neocomian, highly radioactive zone (HRZ). The maturation and generation history of these sediments has been broadly controlled by the Brookian orogeny.

Using well data, trends in generalized source richness, hydrocarbon proneness, and organofacies have been recognized. In projecting these data into the deeper Colville trough, a considerable variation in hydrocarbon generating potential was noted over the Mesozoic section. Several particularly attractive oil-prone units were recognized.

The generic relationship of a wide range of North Slope petroleums--including early, normal, and post-mature or biodegraded examples--was established. A majority of the principal accumulations could be assigned to the previously defined Barrow-Prudhoe oil family. This widespread generic series included petroleums from Upper Cretaceous, Kuparuk River, Ivishak, and Lisburne reservoirs. Lesser, but distinct, Simpson/Seabee-type oil groupings were also recognized.

Effective source-to-oil correlation was achieved by a comparison of the carbon isotopic compositions of the kerogen pyrolyzates and the crude oils. The possible contributions of the various source units were assessed in terms of isotopic match, source potential, and volumetrics. Assuming continuity of source characteristics into the deeper Colville trough, a Triassic/Jurassic combination constituted the closest source match to the major oil accumulations.

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