Dunnottar, Jade South, Edinburgh, Iving and King/Prince; the names of these recently drilled or soon to be drilled targets all share one thing; the main reservoir is the Triassic.
Although not all successful – Dunnottar is thought to have found only marginal amounts of hydrocarbons and the disappointing Iving appraisal campaign probably made Mol Norway decide to mothball operations in Norway – it is clear that the Triassic is still seen as an important reservoir candidate.
See also: Triassic North Sea reservoirs underexplored
What is now called Birgitta was discovered as Fiddich in 1984 by Occidental through drilling 22/19-1. The structure comprises of two tilted fault blocks, named Fiddich Main and Fiddich East. The 22/19-1 well drilled the Main compartment and produced 15.07 mmscfd and 1519 bpd of condensate upon test from the Skagerrak Formation at a depth of around 3,850 m.
The well also proved a thin oil column in the Forties within a low relief structure, which again shows the similarity with Dunnottar as Paleocene oil was found in well 30/08-4 too.
The volume found in the main compartment of Birgitta amounts to 12.78 MMboe according to the Relinquishment Report operator Talisman submitted in 2011, concluding that the capacity and commercial issues precluded a successful development.
Now it is Petrogas’ turn to prove that there is indeed a further 6.7 MMboe in the East compartment, through drilling well 22/19a-8 that was spudded on January 30th. According to Talisman, Birgitta East is thought to be more complex a structure, but at the same time the outlines are well defined and a seismic flat spot also provides confidence for the presence of a hydrocarbon column (see seismic section above).
With Petrogas being 100% owner of the licence, upon a successful well result the company will need to agree on an export route with the most likely candidates – the ETAP or Montrose clusters to the south and west of Birgitta respectively.
HENK KOMBRINK
