Schiehallion oilfield

The Schiehallion oilfield is a deepwater offshore oilfield approximately 175km west of the Shetland Islands in the North Atlantic Ocean. The Schiehallion and adjacent Loyal field were jointly developed by BP on behalf of the Schiehallion field partners; BP, Shell, Amerada Hess, Murphy Oil, Statoil and OMV, and the Loyal field partners; BP and Shell.The Schiehallion field, together with Foinaven, Clair, Lancaster and Solan fields, forms the frontier area generally termed as the West of Shetland.Field developmentSchiehallion field was discovered in 1993 by the semi-submersible drilling vessel Ocean Alliance while drilling the third exploration well in block 204 (well 204-3). The field is located in blocks 204/20 and 204/25 of the United Kingdom Continental Shelf in a water depth of 350to. Recoverable oil reserves of Schiehallion are estimated to be between 450and.During 1994 and 1995 an appraisal of Schiehallion and Loyal was carried out, culminating in a successful extended well test, which demonstrated well rates of up to. The combined development of the Schiehallion and Loyal fields was sanctioned in April 1996 and the oil production started on 29 July 1998.The design and construction of the Schiehallion FPSO vessel was contracted to the Atlantic Frontier Alliance, an ad hoc contracting consortium consisting of Harland and Wolff, SBM Offshore, and Brown and Root. The vessel was designed as a simple barge form, with a 245m length similar to a Suezmax tanker. The contract was placed in June 1995. The vessel was constructed at the Harland and Wolff shipyard in Belfast, and handed over to operator BP on 31 December 1997. The vessel has a dead-weight of, a processing capacity of, and a storage capacity of.