Phases of constructing at the Frigg field

Harald Tønnesen, Norwegian Petroleum Museum

The Frigg field was discovered in 1971, and was at this time the world's largest offshore gas field. The gas was mainly methane (95%), mixed with other hydrocarbons and some liquid condensate. The construction of the Frigg field was organized in three phases.

— Night at Frigg. Photo: Jan A. Tjemsland/Norwegian Petroleum Museum

Phase I – 1977

Phase I involved development of the British side, with concrete drilling platform 1 (CDP1), treatment platform 1 (TP1), the flare platform (FP), the quarters platform (QP), a 32-inch pipeline running for 360 kilometres from TP1 to Scotland, the manifold compression platform 01 (MCP-01) midway between Frigg and the mainland, and the receiving terminal at St Fergus.

Phase II – 1978

The second phase covered the development of the Norwegian share, with drilling platform 2 (DP2) and treatment compression platform 2 (TCP2) and a 32-inch pipeline running for 360 kilometres from TCP2 to Scotland. Phase III was the expansion of TCP2 with compressors to maintain gas pressure from the field.

Phase III – 1981

The pressure in the Frigg reservoir declined as the gas was produced. Since the British Gas Corporation required deliveries at a constant pressure, equipment had to be installed on Frigg to achieve this in the pipeline. The contract with BGC stated that Frigg should deliver the gas with a pressure of 44 bar. In 1981 extra compressors were installed on TCP2. The compressors were able to keep the pressure at 150 bar.

Later TCP2 was upgraded to be able to recieve gas from North-East Frigg, East Frigg, Lille-Frigg, Frøy and Odin. During the following years parts of the process equipment and some wells were modified.

See technical drawings and documentation in the article Technical Documentation – the Frigg Field.