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.