CNOOC Limited has started production from the Luda 10-1 comprehensive adjustment project in the Bohai Sea off China.
A wellhead platform has also been built at the oilfield in Liadong Bay, where there are currently 13 producing wells.
A total of 3,300 barrels of crude are produced per day at the site.
The adjustment project is expected to reach peak production of around 6,000 barrels of crude oil per day in 2016.