CNOOC makes major discovery in ultra-deepwater Liwan 4-1 structure

This can produce 430,000 cubic metres daily.

China National Offshore Oil Corporation (CNOOC) has struck a major gas discovery in China's deep waters, drilling a natural gas well in the Liwan 4-1 structure that produces 430,000 cubic metres of gas per day.

In a statement, the company said the well is located in Baiyun Sag, the largest hydrocarbon-rich sag in the Pearl River Mouth Basin, about 300 kilometres southeast of Shenzhen with a water depth of nearly 1,640 metres. It was drilled to a vertical depth of nearly 3,000 metres, completed at a depth of nearly 4,400 metres, and encountered a gas pay zone of approximately 650 metres in the horizontal section. 

This discovery has opened up new exploration opportunities in China's deepwater Globigerinid limestone, boosting the search for gas in the Baiyun Sag, CNOOC 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,” said Xu Changgui, chief geologist at CNOOC.

“In addition, this discovery is close to the existing production facilities of Liwan3-1 gas field, which could be utilised 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,” he added.