The two fields have produced a combined total of nearly 400 million barrels of oil since 1998, however fresh estimates suggest that there are a further 450 million barrels still available, much more than originally thought.
Since 2012, a number of companies of all shapes and sizes based in Aberdeen, Shetland, Fife and other UK locations have benefitted from the contracts that have been awarded.
The on-going £3 billion upgrade of the fields is aimed at extending production to 2035 and beyond.
Due to the water depth in the area, Schiehallion is entirely reliant on subsea production technology and is collected on a floating production, storage and offloading vessel.
