The concession has been extended to the end of 2041, adding more than 15 years to the original terms.
Upper Zakum is being jointly developed by Inpex, Abu Dhabi National Oil Company and ExxonMobil.
A number of fiscal terms and conditions have also been changed for the concession.
The Upper Zakum is one of the largest oilfields in the world.
Development work is being carried out using artificial islands, while the production capacity is targeted at 750,000 barrels per day.
Joint
