Over recent years, a number of significant oil and gas offshore discoveries and successful appraisal programmes have been reported in China, even though it is often unclear if the “discoveries” are part of an already producing complex or new standalone success. Press releases need unravelling to understand whether volumes are recoverable or in-place. Nevertheless, the results offshore China seem to be impressive, especially the success in basement plays.
In 2017, CNOOC announced the Bozhong 19-6 oil and gas discovery in Bohai Bay, one of three major bays in the Bohai Sea. Exploration well 19-6-1 discovered resources in the range of over one billion barrels of light oil and 6 TCF of gas in Pre-Cambrian basement in a buried hill play. The discovery represents one of China’s biggest hydrocarbon offshore discoveries and first significant gas discovery in the Bohai Bay. In 2020 CNOOC announced the Kenli 6-1 oil discovery in Bohai Sea. Well KL6-1-3 proved up the Mio-Pliocene potential of the Laibei Lower Uplift in Laizhou Bay.
During the same year CNOOC made the Huizhou 26-6 discovery in the Pearl River Mouth in the South China Sea. The discovery well HZ26-6-1 tested oil and gas, and this is the first time that CNOOC has achieved commercial and highly productive flows in a buried hill play in the Pearl River Mouth Basin.
Following the Bozhong 19-6 discovery in basement in the Bohai Bay success continued in early 2021 with the Bozhong 13-2 oil and gas discovery. Later in 2021, CNOOC declared that the Kenli 10-2 was a heavy oil discovery in Laizhou Bay in the Bohai Sea. The Kenli 10-2-4 well encountered oil in Mio-Pliocene sediments.
See also: CNOOC makes largest offshore hydrocarbon discovery in special rock formation. What is that about?
The following year CNOOC announced the Baodao 21-1-1 deepwater gas discovery located in the South China Sea. Baodao 21-1 is reported to have certified proven in-place gas of over 1.8 TCF plus light oil in Oligocene reservoirs.
Early 2023, CNOOC announced that the Bozhong 26-6 oil and gas discovery and been re-appraised in the Bohai Sea. Total proved in-place volumes increased to 1.2 billion barrels of oil equivalent. CNOOC consider Bozhong 26-6 to be the largest metamorphic buried hill oilfield in the world. Later in 2023, CNOOC announced its first offshore unconventional discovery in the Beibu Gulf. The operator’s Weiye-1 wildcat well had a modest flow rate but is considered to have opened the door for more significant unconventional exploration in the Beibuwan Basin.
In March 2024 CNOOC’s QHD27-3-3 made an oil discovery in the northern Bohai Sea. The main oil-bearing Mio-Pliocene reservoirs at Qinhuangdao 27-3 tested medium to heavy crude. During the same month CNOOC announced an oil discovery designated Kaiping South in the deepwater of the eastern part of the South China Sea. The KP18-1-1d discovery well encountered oil-bearing Eocene and Oligocene reservoirs.
