The Clyde oil field is a crude oil producing field in the UK sector of the North Sea, 290 km east-south-east of Aberdeen. Production of oil started in 1987 and the field is still operational (2021).
The field The Clyde oil field is located in Block 30/17b of the UK North Sea continental shelf. It is named after the Scottish river. The Clyde field was discovered in 1978 and the oil reservoir comprises an Upper Jurassic sandstone at a depth of . The reservoir and its fluids has the following characteristics: +Clyde reservoir and fluidsParameterValuePorosity0.23%Permeability105 mdAPI gravity38.1°APIGas Oil Ratio477 standard cubic feet/barrelSulfur content0.3%Recoverable reserves 154 million barrels, 17.7 million tonnes
Owners and operators The initial owners of the field were Britoil (51%), Shell UK Ltd (24.5%) and Esso Petroleum Company Ltd (24.5%). Britoil was the operator. BP assumed ownership of Britoil assets in 1988. BP sold its interest in Clyde to Talisman in 1996. The company became Talisman Sinopec Energy, then Repsol Sinopec.
Development The Clyde field was developed by a single integrated drilling, production and accommodation platform. The principal design data of the Clyde platform is given in the following table. +Clyde platform design dataCoordinates56.452778N 2.288333EWater depth, metres80Fabrication substructureJohn Brown Earl & WrightJacket weight, tonnes12,300Topsides design Humphreys & GlasgowTopsides weight, tonnes17,259FunctionDrilling, production, accommodationAccommodation (crew)207TypeSteel jacketLegs8Piles 26Well slots30 (23 production, 5 water injection)Throughput oil, barrels per day (bpd)60,000Water injection, bpd100,000Platform installedSummer 1985, May 1986Production startedLate 1987Oil production toFulmar A by 9.85 km 16-inch pipelineGas production toFulmar A by 9.85 km 16-inch pipeline
Processing Oil from the wellheads and subsea tie-ins is routed to the 1st stage 3-phase (oil, gas, water) separator. Oil then flows to the 2nd stage and 3rd stage separators operating at successively lower pressures. After metering the oil is pumped to the Fulmar A platform for storage and tanker loading.
Produced water from the separators is treated in a degassing vessel and hydrocyclones to an oil-in-water concentration of less than 30 ppm prior to discharge overboard.
Gas from the separators is compressed in the LP Compressor, Intermediate Pressure (IP) Compressor, HP Compressor and Export/Lift Compressor. There is also a gas dehydration plant. Gas in excess of that required for gas lift is exported to Fulmar A and then to the SEGAL system to St. Fergus terminal.
The fluid handling capability of the Clyde facilities in its latter years was as follows: +Clyde processing capabilityClyde process facilityCapacityCrude oil export60,000 bpdGas dehydration42 MMSCFDProduced water treatment97,000 bpdWater injection73,000 bpd
Other fields Several subsea fields are connected to Clyde through flowlines and pipelines. These fields include Leven, Medwin, Nethan, Orion, Cawdor and Flyndre. There are dedicated Separators on Clyde for the Orion and Flyndre fields. Data on these fields are as follows: FieldCawdorFlyndreLevenMedwinNethanOrionBlock30/1430/1330/17b30/17b30/1730/18Water depth, m707086.975Reserves, million tonnes10.5 million barrels0.1 million Sm31.030.48Production start20171992199420041999Peak production, million tonnes per year5,000 bpd10,000 bpd0.240.1813.1 ton thPipeline20.46 km20 km 8.5-inch pipeline16.3 km 10-inch pipeline The Flyndre field is located in the Norwegian sector of the North Sea. Production began in March 2017.
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