China discovered its first large deep-water deep-stratum gas field with proven reserves exceeding 50 billion cubic meters (bcm) in the sea southeast of Hainan Province, marking strong progress for the country in accelerating deep-sea exploration which will further ensure national energy security.

According to the China National Offshore Oil Corp (CNOOC), the gas field called "Baodao 21-1" achieved the biggest drilling breakthrough in the Songnan-Baodao area in more than 50 years. It was discovered after drilling 5,188 meters into the seabed, 1,570 meters from the water surface.

In the fields that are the targets of offshore oil and gas exploration, waters with a depth of more than 300 meters are generally referred to as deep water, and wells with a depth of more than 3,000 meters are defined as deep wells.

CNOOC made the discovery during their fifth attempt to explore the Baodao Sag. The previous four attempts all failed.

"This discovery not only proved the potentials of the Baodao Sag," Wu Keqiang, chief geologist at CNOOC's Hainan branch, told China Energy News. "But also marked an important breakthrough in our exploring technologies."

"Exploration has always been a priority for CNOOC and we have accelerated the pace to explore the deep waters, targeting the discovery of large and medium-sized oil and gas fields," said Zhou Xinhuai, chief executive officer of CNOOC Limited.

"CNOOC has always emphasized geological theory and technological research to make breakthroughs and to bolster our efforts in reserves and production growth."

"China's deep-sea and deep-earth exploration technology is world-class, and the discovery will not only further advance the development of related exploration technology but also serve as a way for the country to showcase its advanced technology to the world," Lin Boqiang, director of the Center for Energy Economics Research at Xiamen University, told the Global Times on Thursday.

"Deep Sea No.1" was put into use on June 25, 2021, and has produced more than 2 bcm of natural gas, the Xinhua News Agency reported. 

Image source: CNOOC