China's state-owned offshore monopoly producer China National Offshore Oil Corp says it supports the Chinese government's position over Japan's recent protests about Chinese drilling activity in the East China Sea.
"We do not understand the stance of the Japanese side," a spokesperson for CNOOC said Friday in an emailed response to questions on the matter.
On Wednesday, Japan's Chief Cabinet Secretary Yoshihide Suga said China appeared to be building a drilling rig 26 kilometers (16 miles) west of the median line dividing China and Japan's overlapping Exclusive Economic Zones in the East China Sea.
Japan considers the median line to be the appropriate dividing line while China does not.
Suga said Japan would not tolerate such drilling activity in the area as both sides have yet to demarcate their EEZs.
The CNOOC spokesperson did not confirm if the drilling rig belonged to the company but said the East China Sea was one of its four main oil and gas development areas offshore China.
At a daily press briefing on Wednesday, China's Ministry of Foreign Affairs' spokeswoman Hua Chunying had said the Japanese claims were baseless as all activity is limited within Chinese waters.
"China does not accept Japan's protests. China is carrying out development activities in China's jurisdiction and is beyond reproach," she had said, according to a transcript of the briefing on the ministry's website.
The CNOOC spokesperson said the company supports Beijing's position. CNOOC has been exploring in the East China Sea since the 1980s and discovered the Chunxiao, or Shirabaka, cluster of gas fields in 1995.
It lies just outside the EEZ claimed by Japan. CNOOC subsequently developed the gas cluster, including installation of a production platform and an undersea pipeline.
In 2007 CNOOC said it started producing from the Tianwaitian prospect at Chunxiao, which made the Japanese fearful that gas reserves in their own EEZ were being siphoned off through production on the Chinese side.
China and Japan then agreed on a 2,600 square kilometer joint development zone in the northeastern part of the Xihu Trough in mid-2008.
Included in this pact was an agreement for joint development of Chunxiao, on Chinese production sharing terms. Since then however, there has been slow progress and occasional skirmishes near the disputed Diaoyu islands -- known as Senkaku in Japan -- between both countries' maritime vessels have raised tensions.
Actual production from the East China Sea remains small. Last year CNOOC reported about 1,370 b/d of crude and liquids production from the area, stable from 2011 volumes. Natural gas output rose 27.3% year on year to 34,520 Mcf/day.
