CNOOC may have opened a new carbonates exploration play in ultradeepwater offshore China.
A well drilled in nearly 1,640 m of water into the Liwan 4-1 structure in the Pearl River Mouth basin produced 430,000 cu m/d of absolute open flow natural gas during testing.
The location is in the Baiyun Sag, about 300 km southeast of Shenzhen. The well, which was drilled to a vertical depth of almost 3,000 m and completed at a depth of nearly 4,400 m, intersected a gas pay zone of 650 m in the horizontal section.
CNOOC now sees potential for further exploration of prospects in the ultradeepwater Globigerinid limestone in China.
Chief geologist Xu Changgui said, "Previously, exploration in China's ultradeepwater 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 ultradeep waters, marking significant breakthroughs in both exploration understanding and operational techniques.
“In addition, this discovery is close to the existing production facilities of Liwan 3-1 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."
