CNOOC Ltd, China's leading offshore oil/gas producer, said it has successfully appraised a new oilfield, the largest discovered in the Bohai Bay in recent years.

One well in the Penglai 9-1 field is tested to have a daily yield of around 700 barrels, the company said. The field was discovered in 2010.

"I believe the assessment of PL9-1 will open up new prospects for exploration and development in the eastern Bohai Sea and contribute to stable production in the whole region," said Li Fanrong, chief executive of the Beijing-based company.

CNOOC also announced the discovery of Penglai 15-2, just 8km south of Penglai 9-1. Test indicated that the reserve can produce 1,200 barrels of oil per day. Sanford C. Bernstein analyst Neil Beveridge said he saw this as a medium sized discovery.

Penglai 9-1 is about 40km northeast of Penglai 19-3, which is CNOOC's largest oilfield off the coast of China.

Penglai 19-3 has been closed following two oil spill accidents last June. Beveridge said he expects CNOOC to announce the resumption of Penglai 19-3 production soon.