CNOOC achieves "breakthrough" in ultra-deepwater natural gas exploration

Chinese state-owned oil and gas company CNOOC has successfully drilled a natural gas well in the ultra-deepwater Liwan 4-1 structure, located in the Pearl River Mouth Basin. In a statement published on September 10, the company announced that the well achieved a test output of 430,000 m³/day of absolute open flow natural gas, marking a "significant exploration breakthrough" in ultra-deepwater carbonate rocks offshore China.

The well is situated in Baiyun Sag, the largest hydrocarbon-rich area within the Pearl River Mouth Basin, in waters around 1,640 metres deep. It was drilled to a vertical depth of nearly 3,000 metres and completed at around 4,400 metres, encountering a gas pay zone of about 650 metres in the horizontal section.

According to CNOOC, this discovery opens up new exploration opportunities in China's ultra-deepwater Globigerinid limestone formations and further advances natural gas exploration efforts in Baiyun Sag.

"Exploration in China's ultra-deepwater regions has historically focused on clastic rocks. This well demonstrates the immense potential of carbonate rocks at these depths, marking a major advancement in both exploration techniques and geological understanding," said Xu Changgui, CNOOC's chief geologist.

Additionally, the well’s close proximity to the Liwan 3-1 gas field’s production facilities offers potential for rapid development, utilising existing infrastructure, the company noted.