Murchison oilfield
The Murchison oil field is located in the northern North Sea in the East Shetland Basin on the UK Continental Shelf. The field is situated 150 km north-east of Shetland and straddles the UK/Norwegian median line. It lies in UK Block 211/19 and extends into Norwegian Block 33/9. The field is named after the Scottish geologist Sir Roderick Impey Murchison. Recoverable reserves were estimated to be 340 million barrels of oil out of a total oil-in-place of 790 million barrels. The field was developed through a large steel jacket platform standing in 156 m of water. The peak production rate was 150,383 barrels of oil per day in December 1982. Oil production was supported by gas and water injection. Production ceased in 2014 and the platform was removed in 2017.
History
The Murchison oil field was discovered in 1975 by Conoco (UK) Ltd. The reservoir is a Middle Jurassic Brent Group sandstone sealed by Upper Jurassic shales. The oil is unsaturated and had a gravity of 36° API, and without a gas cap. The topsides for Murchison were designed by Matthew Hall Engineering which was awarded the contract in November 1976. Construction was by McDermott Scotland at their Ardersier yard. Initially there were facilities for ten oil production wells, ten water injection wells, two gas injection wells and five spare slots. The production capacity was 164,000 barrels of oil per day and 1.3 million standard cubic metres of gas per day. There was a single production train with three stages of 3-phase of oil, gas and water separation; the first stage separator initially operated at 45 barg. Electricity generation was powered by two 19 MW Rolls-Royce Olympus C gas turbines. The topside accommodation was for 200 people. The topsides weighed 16,000 tonnes and there were 16 modules supported by an eight leg steel jacket of lift weight 24,640 tonnes.The British and Norwegian government licensees entered into an agreement in 1979 concerning common exploitation of the resources on the Murchison field.