Three main reservoirs, in the Brent, Dunlin and Statfjord formations, make up the field. No decision was made in the original unitisation agreement on the treatment of resources in Dunlin.
The redetermination was required because it was decided to include Dunlin in the reserve base for Statfjord. Since that formation lies almost wholly in the Norwegian part of the field, the result was that Norway’s share increased from 85.24 per cent to 85.47 per cent.
Although this change might sound small, it called for an adjustment to the division of oil volumes which took two years to complete and meant the Norwegian licensees received roughly 6.9 million barrels in return from the British partners.
To learn more, see: The final redetermination, 1995-98
Lavik, Håkon. Statfjord. The largest oilfield in the North Sea . Stavanger 1997, p 131.