Evidences for Pre-Jurassic oils in the North Sea

Embla field producing oil from Permian and Devonian reservoirs:     Reservoir sand with GC trace of produced oil:     Core plugs of Embla rhyolites with GC of biodegraded oil, and re-generated waxy oil from the biodegraded oil. The latter was trapped in fluid inclusions roughly 200Ma ago, ie. Pre-Jurassic:     Typical Kimmeridge oil with low wax, concave n-alkane profile, absence of gammacerane whereas Paleozoic sourced oils are different:  ...
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Background

Oils are known to have been generated by pre-Jurassic source rocks on the British Continental Shelf (e.g. British Geological Survey 2016, Peters et. al. 1989). The large variation in oil composition in different compartments of the J-Block discussed by Lines and Auld, 2004, may as well reflect contribution from source rocks of various ages. On the Norwegian part of the North Sea Paleozoic generated oils are described from the Embla Field (Pedersen et al., 2006; Ohm et al., 2012; Abay et al., 201...
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Petroleum potential

E-W interpreted seismic line showing the main Paleozoic petroleum system proposed for the southern North Sea, Sørvestlandet High area (Doudouh, 2017) Source Rock and Migration in the Sørvestlandet area The Mesozoic formations that are the main source rocks in the Central Graben (Mandal, Haugesund and Farsund Formations) (Glennie, 2009) are mostly immature in the Mandal High, Sørvestlandet High area. The Jurassic source rocks in the Søgne Basin are too shallow to have generated and expell...
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