Oseberg (Norwegian: Osebergfeltet) is an offshore oil field with a gas cap in the North Sea located 140 km (87 mi) northwest of the city of Bergen on the southwestern coast of Norway.

The ancient Viking ship from the early 9th century was discovered in a 1904 historical excavation of a burial mound at the Oseberg Farm, south of Oslo.

The first exploration well on the PL079 license, 30/9-1 was drilled as a wildcat at the end of 1982, but treated as an appraisal after it encountered oil and gas considered to form part of the same accumulation.

[7] Tests are also being carried out on the overlying Upper Cretaceous Chalk Group reservoir to evaluate the flow characteristics.

Horizontal drilling close to the oil-water contact was considered key to prolonging the plateau oil production period and achieving high recovery rates.

Injection gas used for pressure maintenance was previously brought from Troll Øst (TOGI) and Oseberg Vest.

This part of the northern North Sea has been affected by two main rift episodes; in the Permo-Triassic and the mid-late Jurassic.

[13] The main reservoirs are sandstones of the Middle Jurassic Oseberg, Rannoch, Etive, Ness and Tarbert formations of the Brent Group.

The Oseberg formation represents the deposits of a series of sand-rich deltas that advanced westwards from the Norwegian coastline.

The rest of the group are the deposits of the massive northward prograding Brent delta system, which occupied the entire southern part of the Viking graben area.

[15] The uppermost Tarbert formation may represent reworked delta plain deposits at the onset of the marine transgression shown by the overlying claystones of the Viking group.

[16] The Brent Group reservoirs, which lie at depths between 2300 and 2700 m, generally have excellent properties with porosities around 20–30% and permeabilities ranging up to several darcys.

The top of the unit, which consists of calcareous sandstones, shows a relatively sharp transition to the dark shales and siltstones of the overlying Dunlin group.

[2] The top seal is formed by Upper Jurassic Viking group or Lower Cretaceous Cromer Knoll claystones.