The second phase of Shenhai-1, China's first self-developed ultra-deep-water gas field, commenced production on Friday, said its operator CNOOC Limited.

Located in the Qiongdongnan Basin, northern South China Sea, with an average water depth of about 900 meters, the project is expected to reach peak production of 162 million cubic feet of natural gas and 3,931 barrels of condensate per day in 2025, said the offshore oil and gas production company.

The project has successfully overcome the challenge of deep-water high-pressure oil and gas reservoir development, said Wang Dongjin, chairman of the company.

CNOOC Limited will accelerate the development of new quality productive forces of marine energy and strengthen the exploration and development of deep-water oil and gas resources in the years to come to further contribute to the high-quality development of China's offshore oil industry, he said.