Updated on March 31, 2025, at 12:30 p.m.
TAIPEI, Taiwan – The China National Offshore Oil Corporation, or CNOOC, has discovered an oilfield in the South China Sea with proven reserves exceeding 100 million tons, Chinese state media said on Monday.
The oilfield in the eastern South China Sea – the Huizhou 19-6 oilfield – was about 170 kilometers (106 miles) from the city of Shenzhen in southern China’s Guangdong Province, the Xinhua News Agency reported.
Test drilling of the oilfield, which has yielded a daily production of 413 barrels of crude oil and 68,000 cubic meters of natural gas, it added.
RFA could not independently confirm the claims.
In a press release, CNOOC said the discovery well was drilled and completed at a depth of 5,415 meters -- what it characterized as “ultra-deep layers” -- facing high temperatures and pressures.
Xinhua cited Peng Guangrong, a geologist at CNOOC’s Shenzhen branch, as saying that 60% of the world’s newly discovered oil and gas reserves have come from deep layers.
The South China Sea is reputed to be rich in hydrocarbons but remains mostly underexplored because of territorial disputes. However, most discovered oil and gas reserves are in uncontested areas, according to the U.S. Energy Information Administration.
China claims almost all of the South China Sea – through which US$3 trillion in commerce moves annually – overlapping with sovereignty claims by the Philippines, Malaysia, Taiwan, Vietnam and Brunei. In a case brought by the Philippines, an international arbitral tribunal in 2016 invalidated the basis of China’s expansive territorial claims, but Beijing has ignored the ruling.
Military patrol
The Chinese announcement on the oil field came days after Pentagon chief Pete Hegseth met his Filipino counterpart Gilberto Teodoro and Philippine President Ferdinand Marcos Jr on Friday in Manila, as part of Hegseth’s Asia-Pacific tour that also included Guam and Japan.
Hegseth reaffirmed Washington’s “ironclad” commitment to its defense treaty with the Philippines, vowing to deploy advanced military capabilities to bolster deterrence against threats, including Chinese “aggression.”
“Deterrence is necessary around the world, but specifically in this region, in your country, considering the threats from the communist Chinese,” Hegseth said.
RELATED STORIES
US to send advanced military hardware to Philippines
Pentagon chief Hegseth heads to Philippines amid South China Sea tensions
Philippine envoy: Manila’s defense alliance with Washington ‘remains intact’
The same day, the U.S., Japan, and the Philippines conducted joint naval drills near the disputed Scarborough Shoal in the South China Sea to enhance crisis preparedness. A Chinese military vessel reportedly monitored the exercises from a distance.
At one point, a Chinese frigate attempted to approach the area where warships and aircraft from the three allied nations were carrying out maneuvers.
However, a Philippine frigate issued a radio warning, prompting the Chinese vessel to keep its distance.
For the first time since these joint naval exercises began last year, known as the Multilateral Maritime Cooperative Activity, a select group of Manila-based media was granted access to observe the drills at sea.
China said it also conducted a military patrol in the South China Sea on Friday.
Edited by Mike Firn.
Updated with edits throughout.