Project Profile
Location: 230km north-west of Stavanger between the continental shelves of the UK and Norwegian borders in North Sea
Reserves: 192 billion Sm³ gas (a recovery rate of 78%)
Start-up year: September 1977
Production ends: 2004
Decommissioning Complete: February 2009
The Frigg field was discovered in 1971 in Norwegian Block 25/1 and UK Block 10/1. It was shut down in 2004 after 27 years of production. Following the discovery, the UK and Norwegian Governments signed an agreement called the Frigg treaty to regulate exploration and production of gas from the Frigg reservoir. The treaty declared that 60.82% of the reserves are located on the Norwegian side and nearly 40% on the UK side.
This Eocene Frigg Sandstone Formation is the main reservoir of the field and is located at a depth of 2,000m.
During its production life the Frigg field had five platforms: the QP, TP1, TCP2, CDP1 and DP2.
Frigg Pipelines
The Frigg field consists of two main 32in pipelines and many other pipelines connecting the installations on the field and the subsea fields Lille-Frigg, North East Frigg and East Frigg.
Two 32in pipelines were laid down on either side of the UK North Sea and Norwegian North Sea. The 361km pipeline 1 is on the UK side, while the 360km long pipeline 2 is on the Norwegian side. These pipelines are parallel to each other at a distance of 70m and lie at a water depth of 100m and 150m. These pipelines used to transport gas to St Fergus Terminal in Scotland. Although Frigg has now stopped production, the pipelines are still in operation connecting other nearby fields.
Part way along the pipelines between the Frigg Field and St Fergus was the MCP-01 platform. It was used to switch gas between the two pipelines, compress the gas and to inspect and clean the pipelines.
The drilling of wells for the Frigg field was carried out during 1976-79. A total of 48 wells (24 each) were drilled from CDP1 and DP2 platforms. The production of CDP1 began in 1977 and DP2 in 1978.
Field Development
Phase I (1977): The CDP1, TP1, the flare platform (FP), the quarters platform (QP), the MCP-01 and the receiving terminal at St Fergus were developed on the UK side of the field. A 32in pipeline of 361km length was laid from TP1 to Scotland.
Phase II (1978): Development activities on the Norwegian side. Under this phase the drilling platform 2 (DP2), the TCP2, and a 32in pipeline running 360km long from TCP2 to Scotland were constructed. This phase also saw the expansion of TCP2 with compressors to maintain gas pressure from the field.
Phase III (1981): The installation of extra compressors on TCP2 to meet the required deliveries of British Gas Corporation at a constant pressure.
Decommissioning Programme
A total of six installations including a damaged DP1 platform had to be removed from the field. Both governments agreed to clean up and remove the structures on the field except for the gravity base structures of concrete drilling platform 1 (CDP1), treatment platform 1 (TP1) and treatment compressing platform 2 (TCP2).
During 2004-05, the pipelines entering or leaving the manifold compression plant 01 (MCP-01) were bypassed, allowing it to be used after decommissioning.
About 85,000t of steel was removed from the Frigg field and the MCP-01 between 2005 and 2008. Of this 20,000t was taken to Shetland for dismantling and the remaining to Stord. All the steel was recycled.
Operators:
Norwegian licensees
Total E&P Norge: Operator with 47.13% interest
Norsk Hydro: 32.87% interest
Statoil: 20% interest
UK licensees
Total E&P UK: Operator with 100% interest
Contractors:
Saipem 7000: The world\'s largest crane vessel, was deployed to lift and remove the topside modules of 65,000t, to be broken up and recycled. (2012)
Electromagnetic Geoservices (EMGS): Contract to provide 3D EM data acquisition and processing services. (August, 2009)
McDermott: Contract to design platform DP. (1974)
Oceanic Contractors: Installation of four-legged steel platform QP, a holding living quarters, a control room, a helideck and communications. (1975)
Ardyne Point: Construction of TP1, the first concrete gravity base structure (GBS) in the UK North Sea.
Condeep Group (comprising Aker and a Norwegian contractors\' joint venture comprising Furuholmen, Hoyer Ellesfen and Selmer Construction): Construction of TCP2 in the Norwegian North Sea. (1976)
Elf and the Compagnie Française d\'Enterprises Metalliques (CFEM): Design the FP which was used as a safety valve at excessive pressures in the Frigg production system. (1975)
Aker Kvaerner Offshore Partner (now Aker Solutions): Contract for engineering, preparation, removal and disposal of the Frigg installations.
Peterson SBS: Managed the engineering, planning, construction, fabrication and preparatory works to ready the site and barge for the trailer load-in of the module support frame (MSF) from a specialist S600 (skid railed) launch barge.
Veolia Environmental Services: a review of the inventory; decontamination, involving the opening, inspection, sampling and testing of systems, pipelines and vessels; draining of all fluids and the removal of asbestos, waste electrical and electronic equipment.