CNOOC Limited(the"Company",SEHK:00883(HKD Counter)and 80883(RMB Counter),SSE:600938)announces today that it has drilled a natural gas well in the ultra-deepwater Liwan 4-1 structure in the Pearl River Mouth Basin.The well was tested to produce 430,000 cubic meters per day of absolute open flow natural gas,marking the first major exploration breakthrough in ultra-deepwater carbonate rocks offshore China.

The well is located in Baiyun Sag,the largest hydrocarbon-rich sag in the Pearl River Mouth Basin,about 300 kilometers southeast of Shenzhen with a water depth of nearly 1,640 meters.The well was drilled to a vertical depth of nearly 3,000 meters,completed at a depth of nearly 4,400 meters,and encountered gas pay zone of approximately 650 meters in the horizontal section.The well has revealed promising exploration prospects in the ultra-deepwater Globigerinid limestone in China,and effectively promotes the natural gas exploration process in Baiyun Sag.

Mr.Xu Changgui,Chief Geologist of the Company,said,"Previously,exploration in China's ultra-deepwater areas mainly focused on clastic rocks.The success of this well has,for the first time,revealed the enormous potential of carbonate rocks in China's ultra-deep waters,marking significant breakthroughs in both exploration understanding and operational techniques.In addition,this discovery is close to the existing production facilities of Liwan3-1 gas field,which could be utilized to develop the new discovery,thereby,enabling economic and efficient development of natural gas resources in the deep waters of the Pearl River Mouth Basin."