Shallow stratigraphic drilling applied in hydrocarbon exploration of the Nordkapp Basin, Barents Sea

Abstract

The Nordkapp Basin is a Late Palaeozoic rift basin characterised by numerous salt diapirs. The salt was deposited in the Late Carboniferous–Early Permian and has been remobilised several times. Upper Palaeozoic and Mesozoic sediments filled in the basin and were uplifted by salt diapirism in the Early/Middle Triassic, Late Jurassic, Late Cretaceous and Tertiary. Regional uplift and erosion in the Early Tertiary and extensive glacial erosion in the Late Pliocene/Pleistocene removed up to 1200m of the Mesozoic and Cenozoic strata and left them heavily tilted and truncated around the salt diapirs, only covered by a thin sheet of glacial sediments.During much of the Triassic and Jurassic the Nordkapp Basin was a large marine embayment, open to the ocean in the southwest. This allowed deposition of potential hydrocarbon source rocks in anoxic basins during transgressive periods in the Triassic and Late Jurassic. Coastal processes improved the reservoir quality of Upper Triassic to Middle Jurassic sands during regressive periods. One exploration well within the basin and three wells surrounding the basin have produced oil shows, but no commercial discoveries have been made so far. During the review period of the present paper, an exploration well encountered oil and gas in Triassic sandstones in the southwestern segment of the basin. This is the first direct indication of a mature, oil-producing source rock in the Nordkapp Basin and will be important for future exploration of the basin.