CNOOC discovers oil in central Bohai Sea

The operator's chief geologist said the find “challenges the conventional understanding that slope areas merely serve as pathways for hydrocarbons rather than sites for substantial accumulation.”

Dec. 29, 2025

CNOOC Ltd. has discovered oil in the shallow Neogene formations of the central Bohai Sea. The company, in a release Dec. 23, said the find adds over 100 million tons of oil equivalent in-place.

The discovery well at Qinhuangdao 29-6 field was drilled and completed at a depth of 1,688 m, which encountered a total of 66.7 m oil pay zones and was tested to produce about 2,560 b/d of crude oil, the company said.

The main oil-bearing play is Neogene Minghuazhen formation. The oil property is medium-heavy crude.

Xu Changgui, chief geologist, CNOOC, said the discovery was made “through enhanced research on hydrocarbon migration and accumulation models in shallow Neogene slope zones, coupled with technological innovation.” He said the find “challenges the conventional understanding that slope areas merely serve as pathways for hydrocarbons rather than sites for substantial accumulation.” Further, he said, the discovery “highlights the considerable exploration potential of uplifted peripheral slopes in settings influenced by intense extensional–strike-slip faulting.”