The project is expected to reach peak production of about 12,000 barrels of oil equivalent per day in 2022, driving Buzzard's total production to 80,000 barrels of oil equivalent per day.
Located 100 km (62 miles) northeast of Aberdeen with average water depth of about 96 metres, the project will use the existing Buzzard facility and has built a set of underwater production systems, two production wells and two water injection wells.
CNOOC Petroleum Europe Ltd, a wholly owned subsidiary of CNOOC Ltd, is the operator of Buzzard and holds 43.21% interest in the project.
The remaining interests are held by Suncor Energy, Harbour Energy and ONE-Dyas.
(Reporting by Muyu Xu and Shivani Singh; Editing by Edmund Blair)