Variations in source rock potential within the Upper Jurassic – Lowermost Cretaceous in the Danish North Sea sector

The Upper Jurassic – Lower Cretaceous Farsund Formation constitutes the principal petroleum source rock in the Danish North Sea Sector. However, the most prolific parts of the succession, the Bo Member is thermally immature over the major part of the area, and the volume of petroleum actually present in reservoirs in the Danish North Sea sector seems to exceed the volume that can be expected to be generated and trapped from mature Bo Member intervals. Additional sources, presumably deeper intervals of the Farsund Formation, are thus called for to fill the fields actually existing. The present study aims at identifying such possible intervals of prolific source rock within the deeper parts of the formation by organic geochemical and petrographic analysis. The study is carried out within the framework of a detailed sequence stratigraphic subdivision of the Farsund Formation, and potential source intervals are thus tied to well-defined and mappable sequences. Hence two sequences have been identified that may act as supplementary petroleum sources for oil in the Danish North Sea Sector.