Siri

Location and Geology

• The Siri field is situated in block 5604/20 in the north-western part of the Danish sector of the North Sea, approximately 220 kilometers from the coast.
• The field lies at a depth of 2,070 meters in Palaeocene sandstone.

Ownership and Operation

• The licence for the Siri field is owned by Dong Energy (50%), Altinex (20%), and Talisman (30%).
• Dong Energy took over the operator licence from Statoil in 2002.

Production History

• Production on the Siri platform began in 1999.
• Initially, the planned life span of the Siri field was until 2007, but Dong Energy extended it to 2016 and further planned to extend it to 2020.
• Oil production reached 15 million cubic meters by the end of August 2007.
• Production was temporarily halted in August 2009 due to cracks in a subsea structure connected to the oil storage tank. It resumed in January 2010 after a temporary solution involving a drilling rig was implemented.

Field Reserves

• The Siri field has recoverable reserves of approximately 60 million barrels of oil.

Platform and Infrastructure

• The Siri platform is a purpose-built, three-legged, fully integrated jack-up platform designed by Kvaerner Oil and Gas (KOGAS).
• The platform includes wellheads, process equipment, and living quarters. It stands on a steel storage tank with a capacity of 50,000 cubic meters.
• The hull measures 50 meters by 60 meters and is 6.7 meters high. It contains diesel and water storage, electrical rooms, general storage, ventilation, and communication rooms.
• The living quarters are cantilevered out 7 meters and can accommodate up to 60 people, primarily for maintenance and well work-over operations. During normal operations, 21 people man the platform.
• The tank was built by Daewoo in South Korea and transported to Stavanger on the heavy-lift vessel MS Swan. It has an effective storage volume of 50,000 cubic meters and includes stability features such as concrete ballast and buoyancy compartments.

Development and Costs

• The engineering, procurement, construction, and installation (EPCI) project cost for the Siri platform and offloading system (excluding drilling) was just above NKr2 billion.
• The platform was designed with a 20-year life span, although the initial operational life was estimated at about ten years.

Technical Challenges

• The production halt in 2009 was due to the failure of the grouting material applied to fix the caisson, which led to cracks in the subsea structure. A temporary solution involving a drilling rig was implemented to resume production.