{{Short description|British sector of the North Sea natural gas pipeline}} {{about|the pipeline|the x86 status register|FLAGS register (computing)|other uses|Flag (disambiguation)}} {{Use dmy dates|date=December 2016}} {{Use British English|date=December 2016}} {{Infobox pipeline | name = Far North Liquids and Associated Gas System | type = natural gas | photo = | caption = | map = | map_caption = Location of Far North Liquids and Associated Gas System | country = United Kingdom | state = | province = | coordinates = | lat = | long = | direction = north–south–west | start = Brent oilfield | through = North Sea | finish = St Fergus Gas Plant | par = | owner = | partners = Royal Dutch Shell, ExxonMobil | operator = Shell UK Exploration and Production | technical_service_provider= | contractors = | construction= | expected = | est = | decom = | length_km = 450 | discharge = | discharge_bbl_d= | diameter_in = 36 | compressor_stations_no= | compressor_stations= | pumping_stations_no= | pumping_stations= }}
The '''FLAGS''' ('''Far North Liquids and Associated Gas System''') pipeline is a natural gas pipeline in the UK sector of the North Sea which, together with its associated pipelines, is used to transport gas and associated liquids from oil and gas fields in the northern North Sea to the St. Fergus gas terminal.
== Pipelines == The FLAGS system gas pipelines are:<ref name=":0">{{Cite web |title=FLAGS pipeline |url=https://www.shell.co.uk/promos/segal/_jcr_content.stream/1640267679322/40a50366056da97b31f7b690c44d3866906b68f7/flags-asset-fact-sheets-marketing-dec-2021.pdf |access-date=9 November 2022}}</ref><ref>{{Cite book |last=Oilfield Publications Limited |title=The North Sea Platform Guide |publisher=Oilfield Publications Limited |year=1985 |pages=138}}</ref><ref>Shell: 2002 Northern North Sea Pipeline Systems</ref><ref>{{Cite book |last=Department of Trade and Industry |title=The Energy Report |publisher=HMSO |year=1994 |isbn=0115153802 |location=London |pages=143–44}}</ref><ref name=":1">{{Cite web |title=North Sea Transition Authority - Oil and Gas Activity |url=https://www.arcgis.com/apps/webappviewer/index.html?id=f4b1ea5802944a55aa4a9df0184205a5 |access-date=9 November 2022}}</ref> {| class="wikitable" |+FLAGS system gas pipelines !Pipeline number !From !To !Diameter (inches) !Length (km) !Notes |- |PL044 |Brent D |Brent C |24 |4.2 | |- |PL047 |Brent C |Brent B |30 |4.4 | |- |PL052 |Brent B |Brent A |36 |2.3 | |- |PL002 (FLAGS) |Brent A |St Fergus |36 |450 |FLAGS line |- |PL164 (NLGP) |Magnus |Brent A |20 |79 |NLGP |- |PL165 |Murchison |NLGP tie in |6 |3.2 | |- |PL166 |Thistle |NLGP tie in |6 |3.2 | |- |PL200 |Statfjord B |NLGP tie in |6 |3.2 |From Norway |- |PL017 (WLGP) |Cormorant A |Brent A |16 |40.5 |WLGP |- |PL917 |Ninian Central |WLGP tie in |10 |17.7 | |- | |North Cormorant |WLGP tie in |10 |22.5 | |- | |Tampen |FLAGS tie in |32 |23.2 |From Norway |- |PL3039 |Knarr |FLAGS tie in |12 |106 |From Norway |- |PL2633 |Gjoa |FLAGS tie in |28 |130 |From Norway |}
== Installations == FLAGS provides the gas export route for the following installations.<ref>Shell UK Limited (2020) Brent field pipelines decommissioning programme</ref>
* 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
== Infrastructure == The FLAGS pipeline is a {{convert|36|in|mm|adj=on}} steel pipe to API 5L, X60 specification and is {{convert|450.6|km}} long. It starts at Brent 'A' and terminates at St. Fergus near Peterhead in Scotland.<ref name=solutions/> 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.<ref name=solutions>{{cite web | publisher = Energy Solutions International | last1 = Collins | first1 = Alan | last2 = Field | first2 = Graham | url = http://www.energy-solutions.com/pdf/PLM_case_study_Collins_Shell_Expros_Plant_Optimization.pdf | title = Shell Expro's Plant Optimisation and Systems Management Project | accessdate = 2010-03-14 | archive-date = 17 May 2008 | archive-url = https://web.archive.org/web/20080517111954/http://www.energy-solutions.com/pdf/PLM_case_study_Collins_Shell_Expros_Plant_Optimization.pdf | url-status = dead }}</ref>
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
The 16-inch '''Western Leg Gas Pipeline (WLGP)''' transports gas from Cormorant A to Brent A. It also takes gas from Ninian Central and North Cormorant.<ref name=":1" />
Natural gas from the Norwegian Statfjord field is fed through the Tampen pipeline, linking Norwegian and UK gas trunkline networks.
== Inlet specification == The inlet specification for gas transported in the FLAGS system is as follows:<ref name=":0" /> {| class="wikitable" |+FLAGS gas properties !Parameter !Value |- |Carbon dioxide |1.6 % vol max |- |Hydrogen sulfide |2.5 ppmv max |- |Total sulfur |15 ppmv max |- |Water |35 ppmv max |- |Cricondenbar |105 bara max |- |Oxygen |10 ppm max |- |Mercury |0.01 μg/m<sup>3</sup> max |- |Propane + |5.5 %mol min |}
== Capacity and throughput == The FLAGS system has a capacity of 33 million standard m<sup>3</sup>/ day.<ref name=":0" />
Up to the end of 1991 the total cumulative throughput of FLAGS was 49,757 million cubic metres of gas. The throughput over the period 1992 to 2014 (in million cubic metres) was:<ref name=":1" /><graph>{ "version": 2, "width": 800, "height": 200, "data": [ { "name": "table", "values": [ { "x": 1992, "y": 6564 }, { "x": 1993, "y": 6482 }, { "x": 1994, "y": 6430 }, { "x": 1995, "y": 6214 }, { "x": 1996, "y": 6459 }, { "x": 1997, "y": 6948 }, { "x": 1998, "y": 7417 }, { "x": 1999, "y": 7596 }, { "x": 2000, "y": 10307 }, { "x": 2001, "y": 11651 }, { "x": 2002, "y": 10578 }, { "x": 2003, "y": 7890 }, { "x": 2004, "y": 7528 }, { "x": 2005, "y": 8482 }, { "x": 2006, "y": 7579 }, { "x": 2007, "y": 6659 }, { "x": 2008, "y": 5934 }, { "x": 2009, "y": 4176 }, { "x": 2010, "y": 3569 }, { "x": 2011, "y": 1357 }, { "x": 2012, "y": 934 }, { "x": 2013, "y": 848 }, { "x": 2014, "y": 1007 } ] } ], "scales": [ { "name": "x", "type": "ordinal", "range": "width", "zero": false, "domain": { "data": "table", "field": "x" } }, { "name": "y", "type": "linear", "range": "height", "nice": true, "domain": { "data": "table", "field": "y" } } ], "axes": [ { "type": "x", "scale": "x" }, { "type": "y", "scale": "y" } ], "marks": [ { "type": "rect", "from": { "data": "table" }, "properties": { "enter": { "x": { "scale": "x", "field": "x" }, "y": { "scale": "y", "field": "y" }, "y2": { "scale": "y", "value": 0 }, "fill": { "value": "steelblue" }, "width": { "scale": "x", "band": "true", "offset": -1 } } } } ] }</graph>
==References== {{Reflist}}
Category:1982 establishments in Scotland Category:Economy of Scotland Category:Energy infrastructure completed in 1982 Category:Natural gas pipelines in the United Kingdom Category:North Sea energy Category:Pipelines under the North Sea