FLAGS

This article is about the pipeline. For the x86 status register, see FLAGS register (computing).

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Far North Liquids and Associated Gas System

Location

Country
United Kingdom

General direction
north–south–west

From
Brent oilfield

Passes through
North Sea

To
St Fergus Gas Plant

General information

Type
natural gas

Partners
Royal Dutch Shell, ExxonMobil

Operator
Shell UK Exploration and Production

Technical information

Length
450 km (280 mi)

Diameter
36 in (914 mm)

The FLAGS (Far North Liquids and Associated Gas System) pipeline is a natural gas pipeline in the North Sea which is used to transport liquids and associated gas from the following fields:

Cormorant A
North Cormorant
North West Hutton
Ninian Central
Ninian North & South
Brent ‘A’, ‘B’, ‘C’ and ‘D’
Tern
Magnus
Thistle
Murchison
Statfjord
Heather
Gjøa
Gas exported from West of shetland oil fields (Foinaven, Schiehallion/Loyal and Clair)
Knarr

The pipeline is a 36-inch (910 mm) steel pipe to API 5L, X60 specification and is 450.6 kilometres (280.0 mi) long. It starts at Brent ‘A’ and terminates at St. Fergus near Peterhead in Scotland.[1] Pipe laying was completed in April 1978 and finally commissioned in May 1982. The pipeline was laid by SEMAC 1.
At Brent A, the pipeline is connected with the Northern Leg and Western Leg transmission systems, carrying gas from a number of nearby fields.[1] The 20-inch Northern Leg Gas Pipeline (NLGP) runs for 80 km from Magnus to Brent A with spurs to Thistle A, Murchison and Statfjord B. It originally served as the gas export route for these installations and delivered gas to Brent A for onward transmission to St Fergus via FLAGS. As some of these installation have become gas deficient it has served as their gas supply route. The pipeline has depressurisation facilities at Magnus. Gas from the NLGP is heated before flowing via manual pressure let-down valves to the HP and LP flare systems. Pre-heating the gas ensures that it remains within the temperature limits of the flare pipework after Joule-Thomson cooling across the let-down valves.
Natural gas from the Norwegian Statfjord field is fed through the Tampen pipeline, linking Norwegian and UK ga