The Caofeidian 6-4 oil structure in Bohai offshore China discovered in 2014 was appraised successfully and confirmed to be a mid-sized oil field, CNOOC Ltd. said in a news release.

The Caofeidian 6-4 structure is located in the western part of Shijutuo Uplift in the west of Bohai with an average water depth of about 20 m (66 ft). The discovery well Caofeidian 6-4-1 was drilled and completed at a depth of about 3,100 m (10,171 ft) and encountered oil pay zones with a total thickness of about 180 m (591 ft), according to the release.

The well produces light crude oil and production was tested around 5,750 barrels per day. Caofeidian 6-4-1 has set three records in the west of Bohai exploration area in achieving maximum cumulative thickness and maximum single pay thickness of oil pay zones, as well as highest test production in Paleogene clastic rocks, according to CNOOC.