One more ‘major breakthrough’ for China as another ultra-deepwater gas discovery springs up

Chinese state-owned oil and gas giant China National Offshore Oil Corporation (CNOOC) has boosted its natural gas reserves with another discovery, which is said to mark the first major exploration breakthrough in ultra-deepwater carbonate rocks off the coast of China.

While disclosing “another major breakthrough in ultra-deepwater natural gas exploration,” CNOOC confirmed the drilling of a natural gas well in the ultra-deepwater Liwan 4-1 structure in the Pearl River Mouth Basin, which was tested to produce 430,000 cubic meters per day of absolute open flow natural gas.

Xu Changgui, CNOOC’s Chief Geologist, commented: “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 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.”

Located in Baiyun Sag, which is considered to be 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 close to 3,000 meters, completed at a depth of almost 4,400 meters, and encountered gas pay zone of approximately 650 meters in the horizontal section.

According to CNOOC, this well has revealed promising exploration prospects in China’s ultra-deepwater Globigerinid limestone, effectively promoting the natural gas exploration process in Baiyun Sag. This discovery follows the one the Chinese giant confirmed in ultra-shallow gas play in the ultra-deepwater of the South China Sea.

The company has been busy with multiple hydrocarbon exploration and production activities since the start of the year. Last month, the firm announced the approval of the proved gas in place of over 100 billion cubic meters at a hydrocarbon discovery, described as the first large-size ultra-shallow gas field in ultra-deepwater in the world, which adds the final touch to the trillion-cubic-meter gas region in the South China Sea.

The Chinese heavyweight’s first ultra-deep well in Bohai Bay is said to have outperformed its set oil and gas target, while the firm disclosed another hydrocarbon discovery. Less than a week ago, CNOOC started production at an oilfield development project in Beibu Gulf. The ramp-up in offshore drilling is aligned with the firm’s business strategy and development plan for 2024.