CNOOC Ltd, the largest offshore oil and gas explorer in China, announced on Thursday that its Wenchang 19-1 North and Weizhou 12-8 West oilfields have started production.

Wenchang 19-1 North oilfield, an independent oilfield in which CNOOC holds 100 percent interest and acts as the operator, is located in the western Pearl River Mouth Basin with an average water depth of about 120 to 130 meters.

It has three producing wells and is expected to reach peak production within the year, the company said in the announcement.

Weizhou 12-8 West oilfield is located in the Beibu Gulf Basin in the southwest part of the South China Sea with an average water depth of about 34 meters. It has five producing wells and is also expected to reach its peak production within the year.

CNOOC holds 51 percent interest and acts as the operator of Weizhou 12-8 West oilfield. The partners of this oilfield are Roc Oil (China) Company, Horizon Oil (Beibu) Ltd and Oil Australia Pty Ltd.