Trestakk

Trestakk Oil and Gas Field Profile

Location and Geology

• The Trestakk oil and gas field is located in the central part of the Norwegian Sea, approximately 20-25 kilometers south-east of the Åsgard field and 300 meters below the sea surface in block 6406/3 under production license PL091.
• The field's reservoir is situated at a depth of 3,900 meters beneath the seabed and consists of Middle Jurassic sandstones of the Garn Formation.

Discovery and Development

• The Trestakk field was discovered in 1986 by the 6406/3-2 wildcat exploration well in the Halten Bank area of the Norwegian Sea. Further confirmation of the reservoir's productivity was obtained through the drilling of the 6406/3-4 appraisal well in 1987.
• The plan for development and operation (PDO) was submitted to the Norwegian Ministry of Petroleum and Energy in November 2016 and was approved in April 2017. The Norwegian Petroleum Directorate (NPD) granted permission for the start-up of the Trestakk field in May 2019.

Ownership and Operation

• The field is operated by Equinor (formerly Statoil), which holds a 59.1% stake. The other co-owners are ExxonMobil with a 33% stake and Vår Energi with a 7.9% stake.

Development Concept

• The Trestakk field development involves a subsea template with four well slots and an additional satellite well tied-in to it. A total of five wells have been drilled, with three being production wells and two being gas injection wells.
• The subsea installation is tied-back to the Åsgard A floating production storage and offloading (FPSO) vessel through a 12-inch diameter production pipeline. The Åsgard A FPSO has been operating since May 1999 and is expected to have its operational life extended to 2030 due to the Trestakk tie-back.

Production and Recovery

• Oil recovery at the field is supported by gas injection. The processed oil and condensate are temporarily stored at the Åsgard A facility before being shipped to market via shuttle tankers. The produced gas is transported to the Kårstø terminal through the Åsgard Transport System (ATS).
• Initially, production from the field was lower than anticipated due to poorer reservoir properties and lower gas injection volumes. However, starting in mid-2023, an updated gas injection strategy has been implemented, resulting in stabilized production rates. New infill targets are currently being evaluated.

Contractors and Investments

• TechnipFMC was awarded the integrated engineering, procurement, construction, and installation (EPCI) contract for the Trestakk field development in November 2016. The contract included the design, supply, and installation of various subsea components such as flexible risers, production flow-lines, and subsea production systems.
• Aker Solutions was awarded the contract for the Åsgard A topside modification work necessary for the Trestakk field tie-back in November 2016.
• The estimated investment for the Trestakk field development is approximately Nkr4.8 billion (around $548 million).

Reserves and Production Capacity

• The Trestakk field is estimated to hold 67 million barrels of oil and 1.4 billion cubic meters (bcm) of gas in recoverable reserves.

Åsgard A FPSO Details

• The Åsgard A FPSO is a permanently moored, 287-meter-long monohull vessel with a displacement of 184,300 tons. It has the capacity to produce up to 200,000 barrels of oil and 840 million metric cubic feet (Mmcf) of gas per day. The oil storage capacity of the vessel is 907,000 barrels.