Abstract

The greater Utsira High area is located within the southern part of quadrants 24 and 25 and the northern part of quadrants 15 and 16 in the Norwegian North Sea. In this part of the Viking Graben the main exploration play is the submarine fan sands of Paleocene and Eocene age. These sands (Balder, Heimdal, and Ty formations) pinch out to the east in blocks 25/8 (Jotun field) and 25/11 (Balder and Grane fields) and along the western margin of the Utsira High to form a combination of stratigraphic and structural traps. Marine sands of Middle and Late Jurassic age, typically present in rotated fault blocks, constitute another important play.

Geochemical analyses show that the Upper Jurassic Draupne Formation has a good potential for oil generation along the entire western margin and northern nose of the Utsira High. Both upper and lower Draupne source intervals along the western graben margin, however, contain more terrigenous kerogen than in the eastern part of the graben. Such change in organic facies within the Draupne source interval naturally results in a higher proportion of gas generation and the possibility for generating a more waxy crude than typically encountered in the Viking Graben. Detection and characterization of oil and gas shows within the Tertiary section permit mapping of migration entry points from the Jurassic source rocks and help delineate secondary and tertiary migration pathways within the Paleocene-Eocene play.

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