Journal of Petroleum Geology: Characterization of Upper Palaeozoic organic-rich units in Svalbard – implications for the Norwegian Barents Shelf

Jakob Nicolaisen, Geir Elvebakk, Juha Ahokas, Jørgen A. Bojesen-Koefoed, Snorre Olaussen, Joakim Rinna, Jon Erik Skeie and Lars Stemmerik have published a paper titled “Characterization of Upper Palaeozoic organic-rich units in Svalbard – implications for the Norwegian Barents Shelf” in the Journal of Petroleum Geology. The authors represent both academia (NHM Univ.Copenhagen, GEUS, UNIS) and industry (Geo-Moski, Aker BP).

Abstract: 

Recent discoveries of hydrocarbons along the western margin of the Norwegian Barents Shelf have emphasised the need for a better understanding of the source rock potential of the Upper Palaeozoic succession. In this study, a comprehensive set of organic geochemical data have been collected from the Carboniferous – Permian interval outcropping on Svalbard in order to re‐assess the offshore potential. Four stratigraphic levels with organic‐rich facies have been identified: (i) Lower Carboniferous (Mississippian) fluvio‐lacustrine intervals with TOC between 1 and 75 wt.% and a cumulative organic‐rich section more than 100 m thick; (ii) Upper Carboniferous (Pennsylvanian) evaporite‐associated marine shales and organic‐rich carbonates with TOC up to 20 wt.%; (iii) a widespread lowermost Permian organic‐rich carbonate unit, 2–10 m thick, with 1–10 wt. % TOC; and (iv) Lower Permian organic‐rich marine shales with an average TOC content of 10 wt.%.

Petroleum can potentially be tied to organic‐rich facies at formation level based on the gammacerane index, δ13C of the aromatic fraction and/or the Pr/Ph ratio. Relatively heavy δ13C values, a low gammacerane index and high Pr/Ph ratios characterize Lower Carboniferous non‐marine sediments, whereas evaporite‐associated facies have lighter δ13C, a higher gammacerane index and lower Pr/Ph ratios.

Reference: 

Nicolaisen, J.B, Elvebakk, G., Ahokas, J., Bojesen-Koefoed, J. A., Olaussen, S., Rinna, J., Skeie, J. E., Stemmerik, L. (2019): Characterization of Upper Palaeozoic organic-rich units in Svalbard – implications for the Norwegian Barents Shelf. Journal of Petroleum Geology 42, 59-78. DOI: 10.1111/jpg.12724 [intranet]