Claymore oilfield
The Claymore oil field is located in Block 14/19 on the United Kingdom's Continental Shelf. It is northeast of Aberdeen in the Central North Sea. The field is named after a double-edged broadsword used by Highland Scots. Recoverable oil reserves were estimated to be 511 million barrels from an initial oil in place of 1452.9 million barrels. The field was developed through a large steel jacket platform standing in 110 m of water. A separate accommodation platform was installed in 1995. Fluid production was supported by gas lift and significant water injection. The production platform also supports production from the Scapa field, the Golden Eagle field and the Tartan field. Oil is exported to the Flotta terminal.
History
The Claymore field was discovered in 1974 by Occidental of Scotland with well 14/19-2 which penetrated 158 metres of oil sand at a depth of 2,459 metres subsea. The field is subdivided into main, central and northern areas. Production is from Upper Jurassic paralic and turbidite sandstones in the main area, lower Cretaceous turbidite sandstones that overlie faulted Graben margins in the northern area, and Permian carbonates and Carboniferous sandstones in the central area. The oil in place has an API Gravity of 26–33° and a gas oil ratio of 100–400 standard cubic feet per barrel.The topsides for Claymore were designed and procured by Matthew Hall Engineering which was awarded the contract in November 1976. MHE was also responsible for construction supervision. Initially there were facilities for 24 oil production wells, ten water injection wells and two gas injection wells. The production capacity was 180,000 barrels of oil per day. There was initially a single production train with three stages of 3-phase separation; the first stage separator initially operated at 5.9 barg. Electricity generation was powered by two 12 MW Rolls-Royce Avon gas turbines. The original topside accommodation was for 150 people. The topsides weighed 10,000 tonnes and there were four modules supported by an eight leg steel jacket installed in 1976. MHE was awarded The Queen's Award for Enterprise: Innovation in 1980 for the innovative design of production facilities for Claymore A Platform.
Operation
First oil was produced from Claymore in November 1977 and was exported to Flotta Terminal via a 30-inch pipeline. Gas could also be exported to/from the Frigg pipeline system.Two subsea water injection templates were installed in 1981 and 1985.
In 1995 an accommodation platform was installed, linked to the existing Claymore Production Platform by a 106-metre bridge.
As of 2017 Claymore has 32 platform oil production wells; four platform water injection wells; five subsea Scapa oil production wells; and 17 subsea water injection well. Fluids are separated in two horizontal vessels operating in parallel, plus a dedicated Scapa separator. Produced water is treated in hydrocyclones and a degasser vessel prior to overboard disposal. The current capacity of the processing plant, and the ullage available to third party operators, is as follows.
| Plant | Maximum capacity | Maximum capacity | Ullage |
| Claymore Separators | 5% to 25% | - | |
| Scapa Separator | < 5% | - | |
| Oil Export system | > 25% | - | |
| Claymore Produced Water | 5% to 25% | - | |
| Scapa Produced Water | > 25% | - | |
| Claymore Water Injection | 5% to 25% | - | |
| Scapa Water Injection | 5% to 25% | - | |
| Gas Compression system | > 25% | - | |
| Gas export system | > 25% | ||
| Gas Lift system | < 5% | - | |
| Gas dehydration for Scapa gas lift | < 5% | - |
Claymore provides ‘up and over’ transportation facilities for the Golden Eagle field.