Abstract - We report a coupled geochemical, fluid inclusion, structural and basin modelling study of the North Sea's greater Heimdal petroleum system. The Heimdal High has acted as a major conduit for vertical petroleum migration since the early Tertiary. Petroleum generated within the Viking Graben is focused laterally along a faulted Jurassic carrier system to the Heimdal High. Vertical migration through 1-2 km of Cretaceous mudstones to Tertiary sands occurred at the Heimdal High under pressure regimes ranging from hydrostatic to highly overpressured. There is no need to invoke vertical migration through faults and hydrofractures, although this cannot be ruled out. Lateral migration in the Tertiary sands takes place from the Heimdal High feed point; oil and gas migrate laterally and (locally) vertically to reach the highest Tertiary sand at most locations. Most migration to current accumulations is very late in the Neogene. We speculate that vertical migration within the Tertiary may be partly controlled by small-throw polygonal fault systems in places where sand has been injected along the faults.
Journal of Geochemical Exploration,
69-70, 619-622, 2000.