History
The Piper oil field was discovered by the Occidental Group in January 1973 and the adjacent Claymore field in May 1974. Occidental considered a number of options for exporting oil from the planned installations, these included offshore loading and pipelines to shore. Nine potential onshore sites for the pipeline terminal were considered. The island of Flotta was selected as it met operational needs and minimised the impact on the natural environment. The Planning Authority gave planning consent in January 1974 for phase 1 of the development for the Piper field. The terminal (coordinates 58° 20’ 22” N 03° 06’ 24” W) received ‘live’ crude oil fromThe plant
Phase 1 of the development of the Flotta terminal included: * Pipeline reception facilities including a pig receiver * Five 500,000 barrel capacity floating roof crude oil storage tanks * Two stabilisation process trains each with a capacity of 125,000 barrels/day * Propane storage and transfer facilities * Two single point mooring towers in Scapa Flow for tankers up to 200,000 dead weight tonnes (DWT), with 48-inch diameter loading lines * LPG jetty capable of handing ships up to 30,000 DWT * Flare system *Operations
Flotta pipelines
The Flotta oil pipeline system comprises the following lines. The oil entry specification to the Piper to Flotta pipeline and hence to the Flotta terminal is as shown in the table.Processing
Live crude oil from the Piper to Flotta pipeline is routed to one or more of the four 125,000 barrels/day stabiliser trains. The trains include two stages of desalting to remove salt and water from the oil. Oil is heated and enters the stabiliser towers where the lighter fractions boil off. Stabilised crude from the base of the stabilisers is routed to the crude oil storage tanks. The light ends from the top of the stabiliser are compressed and flow to the de-methaniser. The methane and ethane are removed from the top of the vessel and used as fuel gas with the surplus burned in the flare. The flaring rate in 1993 was 40,000 m3/day or 1,460,000 cubic feet/day. Heavy ends from the base of the de-methaniser were routed to the de-ethaniser and then the de-propaniser. Propane from the top of the de-propaniser was chilled and liquefied and stored at –40 °C in two 100,000 barrel capacity insulated tanks. Butane and any heavier ends from the bottom of the de-propaniser are comingled with the stabilised crude. Stabilised crude typically had the following properties. Stabilised crude oil from the storage tanks was routed via 48-inch diameter lines to either of the single point moorings (SPM) in Scapa Flow or to the jetty. LPG was loaded to the jetty. The SPM loading rate was 50,000 BPH. The jetty had an oil loading rate of 80,000 BPH. Ballast water from tankers was pumped to a 500,000 barrel storage tank. It was treated in a floatation unit before discharge via a 1.5 mile 36-inch diameter pipeline into the turbulent waters of the Pentland Firth to aid dispersal.Throughput
The total oil throughput of the terminal up to the end of 1997 was 258,529 thousand tonnes.Digest of UK Energy Statistics (DUKES) Annex F.1 Crude Oil Peak production was 421,590 barrels/day on 4 November 1978. The oil production from 1998 (in 1000 tonnes) was:Ownership
The initial Occidental Group comprised: Occidental of Britain Incorporated, Allied Chemicals (Great Britain) Limited, Thomson North Sea Limited, and Getty Oil Britain Limited. In 1984 the Occidental Consortium comprised Occidental Petroleum (Caledonia) Limited, 36.50%; Texaco Britain Limited, 23.50%; International Thomson plc, 20.00%; Union Texas Petroleum Limited, 20.00%. Following the Piper Alpha disaster in July 1988 Elf Enterprises Caledonia Limited and its partners assumed ownership of the pipeline and the Flotta terminal. Repsol Sinopec Resources UK Limited became the major shareholder and operator in May 2000.Developments
Following commissioning of Piper Alpha in December 1976 the following developments took place. * The Claymore platform came on stream on 14 November 1977, oil production was via a TEE on the Piper Alpha to Flotta trunkline. * The Tartan platform began production to Flotta in 1981 via the Claymore installation. By 31 December 1984 883 million barrels of oil had been processed at Flotta and 1,554 tankers had been loaded. The following fields producing to the Flotta system were developed in the mid 1980s. The Piper Alpha disaster occurred on 6 July 1988. Production from, and via, Piper ceased. The following fields, producing to the Flotta system, were developed from 1989. The Golden Eagle development effectively doubled the production through Flotta terminal. By 2017, 40 years after being commissioned, 2.6 billion barrels of oil had been processed through the Flotta terminal. By 2017 one of the stabiliser trains had been decommissioned. The three remaining trains had a combined capacity of 375,000 barrels/day. By 2017 there were insufficient volumes of gas to make the operation of the gas plant economically viable. There was a proposal to decommission the system. Gas from the stabilisers was used to generate electricity and as fuel gas in the hot oil heaters. The Single Point Moorings have been mothballed and are not operational. As currently operated (2020) the terminal only exports stabilised crude oil through tankers loaded at the jetty. In 2016 50 tankers visited the terminal.See also
*References
{{reflist Petroleum infrastructure in the United Kingdom Petroleum industry in the United Kingdom Oil terminals North Sea energy