A vast body of conventional source rock analyses show that the Kimmeridge Clay Formation of the UK (Draupne or Mandal formations of Norway and Farsund Formation of Denmark) contains large volumes of residual (i.e. unexpelled) oil where buried below about 3.2km. Free oil yields from both Rock-Eval pyrolysis and solvent extraction average at ∼6 kg liquids/tonne rock with a range from 3 – 9 kg/tonne. Unlike most onshore basins where the source rocks are uplifted and hence generation has ceased, the North Sea, with rapid Tertiary-Recent sedimentation, offers the opportunity to drill directly into an actively generating world class oil-prone source rock. Prior knowledge locates sweet spots by selecting optimum maturity, thickness, organic richness and sedimentary facies (lithology) The pyrolysis and extract data quoted above equate to an average 140 bbls/acre.ft with a range of 70–210 bbls/acre.ft), the challenge being to extract it economically.

This content is only available via PDF.
You can access this article if you purchase or spend a download.