Elgin / Franklin
The two fields, with a water depth of 93m, are around five and a half kilometres apart and are both connected to the Elgin PUQ(Production Utility Quarters) platform, which separates produced hydrocarbons into gas and liquid components.
The process system on the Elgin PUQ separates gas from condensate, treats the gas to sales quality and exports the treated gas and condensate through separate pipelines.
Hydrocarbons from the Elgin and Franklin reservoirs are separated and processed on the Elgin PUQ. Liquids are transported via the Graben Area Export Line (GAEL) pipeline and the BP-operated Forties Pipeline System to Cruden Bay, north of Aberdeen. The liquids are then piped south to the BP-operated Kinneil terminal for final processing and storage prior to loading onto oil tankers for export.
Gas is exported via the Shearwater Elgin Area Line (SEAL) pipeline to the Shell-operated Bacton terminal in Norfolk where it is routed either to the UK's National Grid, or via the SEAL Interconnector LinK (SILK) pipeline to the Interconnector Terminal and onwards to Europe.
For more information on commercial availability of ullage in the Elgin/Franklin infrastructure, please go to www.total-icop.co.uk
One of our key technological challenges was to develop equipment to withstand extreme HP/HT conditions – able to operate reliably at a design pressure of 860 bar and at design temperatures between -35 degrees centigrade and +190 degrees centigrade. Design and manufacture of the emergency shutdown valves (ESDVs) took almost five years. They are the largest HP/HT valves in the world. Another challenge was the well pressure during drilling, which varied between 650 bar and 1100 bar. This had to be anticipated and the correct weight of mud calculated to avoid a blowout. To tackle this problem, we developed a new computer program which determined how to control the well pressure by varying mud density, circulation rates and pipe tripping speeds. This meant that the production wells could be drilled at much lower cost than the original exploration wells and with much less risk.
The peak production capability for the Elgin/Franklin Field is 280,000 barrels of oil equivalent per day, 175,000 barrels per day condensate and 15.5 million cubic metres of gas per day.