Production started Monday at the Nexen Petroleum operated Golden Eagle Area Development in the UK North Sea.
Two Golden Eagle wells are producing about 18,000 barrels of oil per day.
The GEAD includes development of the Golden Eagle, Peregrine and Solitaire fields.
The fields are located in blocks 20/1S, 20/1N and 14/26a of the North Sea, 43 miles northeast of Aberdeen, Scotland in average water depths ranging from 291 feet to 456 feet.
The development comprises separate production and wellhead platforms and two subsea production systems.
A total of 15 production wells and six water injection wells will eventually be drilled from these facilities.
The project is expected to reach its peak production rate of about 70,000 barrels of oil per day in 2015.
CNOOC had set its 2014 investment target for the project at about $20 billion.
Calgary-based Nexen Petroleum, a wholly owned subsidiary of China’s CNOOC, operates the GEAD with a 36.54 percent share.
“GEAD was delivered on schedule, on budget, and to world-class safety standards. The GEAD supported in excess of 2,500 jobs in the UK and makes a significant production contribution to the company in the near future,” CNOOC’s CEO Li Fanrong said.
Denmark-based Maersk Oil holds a 31.56 percent share, UK-based Suncor Energy holds a 26.69 percent share and UK-based Edinburgh Oil and Gas holds 5.21 percent share.