Gjøa

Profile for the Gjøa Oil and Gas Field

Location and Geography

• The Gjøa field is located in the northern part of the North Sea, approximately 50 kilometres northeast of the Troll field and 65km southwest of Florø, Norway. It is situated in blocks 35/9 and 36/7.
• The water depth at the field is about 360 metres.

Discovery and Development

• The Gjøa field was discovered in 1989.
• The plan for development and operation (PDO) was approved in 2007. Statoil was the operator during the field development phase, while Gaz de France (now part of Engie) took over as the operator once production began.

Production

• Production at the Gjøa field started in 2010.
• The field produces both oil and gas, with the majority of production being gas. The reservoirs contain gas above a relatively thin oil zone in Jurassic sandstones of the Dunlin, Brent, and Viking Groups.
• The production strategy involves pressure depletion, with oil production prioritized in the early years. Gas blow-down started in 2015, and low-pressure production was implemented in 2017.

Infrastructure and Facilities

• The field is developed with a semi-submersible production facility. The Gjøa production platform is a major hub facility in the region and runs on hydroelectric power generated in Norway.
• The platform's topsides measure 110 meters long and 85 meters wide, weighing just below 20,000 tonnes, while the hull weighs 14,200 tonnes.
• The field includes five 4-slot templates and is partly supplied with power from shore.

Transportation and Export

• Stabilized oil is exported via a pipeline connected to the Troll Oil Pipeline II, which terminates at the Mongstad crude oil terminal in Norway.
• Rich gas is exported through the Far North Liquids and Associated Gas System (FLAGS) to the St Fergus terminal in Scotland.

Partners and Ownership

• The current partners in the Gjøa field include:
  • Neptune Energy (operator, 30% interest)
  • Petoro (30% interest)
  • Wintershall Dea Norge (28% interest)
  • OKEA (12% interest).
• Historical changes in ownership include Statoil reducing its stake to 5% in 2013 and later selling its stake to Wintershall in 2014. OKEA acquired Shell's stake in 2018.

Contractors and Suppliers

• Key contractors involved in the development include:
  • Samsung Heavy Industries: Semi-submersible hull construction
  • Technip: Fabrication and installation of infield pipelines
  • Aker Kvaerner: Manufacture and supply of umbilicals, detail design of topside and hull, and construction of the topside
  • Saipem: Pipeline installation of Gjøa export pipelines
  • Dresser-Rand: Provision of compressor trains
  • ABB: Building a 98-kilometer underwater link from Mongstad.

Gjøa P1 Project

• The Gjøa P1 project, sanctioned in February 2019, targets the untapped oil and gas reserves in the northern part of the Gjøa field. It involves the development of the P1 segment with two new wells and an integrated template structure with four slots. The project is expected to increase the field’s reserves by approximately 32 million barrels of oil equivalent and produce around 24,000 barrels of oil equivalent per day.

Reservoir and Geology

• The reservoir depth is about 2,200 metres, containing gas above a relatively thin oil zone in Jurassic sandstones. The field comprises several tilted fault segments with partly uncertain communication and variable reservoir quality.

Current Status

• Production from the Gjøa field has started to decline. Current work focuses on production optimization, natural gas lift, infill drilling, and near-field exploration targets.

Environmental and Operational Aspects

• The field development includes environmental considerations such as the installation of a 130km gas export pipeline to the FLAGS system, with measures to prevent corrosion and ensure stability.
• The operational phase involves regular pipeline maintenance and the use of chemicals to ensure the integrity of the pipelines.