Song Enlai, chairman of China National Offshore Oil Corp’s (CNOOC) board of supervisors, said in Beijing earlier that the state-controlled company was already pumping oil from Chunxiao gas field, known as Shirakaba in Japan.
Japanese Chief Cabinet Secretary Yukio Edano said Tokyo was looking into the matter after the Asahi newspaper in Japan reported Song’s comments.
“It is very regrettable that a media report naming a CNOOC official has been released. We are checking with the Chinese side about this,” Edano told a news conference.
Ties between the two countries chilled in September following a territorial spat, and the two governments have also been at odds over China’s search for natural gas and oil in an area where sovereignty is contested.
The two countries agreed in 2008 on principles to resolve the gas feud by jointly developing gas fields, but efforts have foundered since then and Japan has accused China of drilling for gas in violation of the agreement.
CNOOC said in a 2006 annual report that it was pumping oil and gas from one of the disputed gas fields. An industry source said back then that the firm was ready to begin producing from Chunxiao as soon as Beijing gave the go-ahead.
Asked about the Chunxiao field, Song Enlai said on Tuesday: “It’s a sensitive question. But we already started developing the field, we are already pumping oil.
“We’ve said that we are ready for cooperation in the disputed area. We are developing in the area which we believe is our sovereign area,” he said.
The East China Sea is a hotbed of frictions between the two neighbors. They are also contesting a group of uninhabited isles, known as Senkaku in Japan and Diaoyu in China, and relations soured in September after Japan held a Chinese trawler captain whose boat collided with Japanese coast guard ships near there.
Rare earth exports to Japan from China were effectively suspended between late September and November after the row, though China denies that it cut exports because of the fishing boat standoff.
This week, Tokyo complained to China after a Chinese helicopter flew too close to a Japanese destroyer in the East China Sea, Japanese Defense Minister Toshimi Kitazawa said.
Japan also scrambled military jets after Chinese naval planes flew near the disputed isles this month, although the Chinese did not enter Japan’s airspace.
Japanese Foreign Minister Seiji Maehara, a security hawk and a critic of China’s defense build-up, resigned on Sunday over a political donations scandal, less than two weeks before Japanese, Chinese and South Korean foreign ministers were expected to hold a trilateral meeting in Japan.
A junior cabinet minister, State foreign secretary Takeaki Matsumoto, is set to become the new foreign minister.
Negotiations between Japan and China over a treaty aimed at joint development of the gas fields began in July, but China postponed the next round of talks to show its anger over the territorial friction.
The trough basin in the East China Sea where the gas fields are located is estimated to hold nearly 17.5 trillion cubic feet of natural gas and could also hold 20 million barrels of oil, according to Chinese estimates.
