The Xihu Trough () is a region in the

East China Sea The East China Sea is an arm of the Western Pacific Ocean, located directly offshore from East China. It covers an area of roughly . The sea’s northern extension between mainland China and the Korean Peninsula is the Yellow Sea, separated b ...

, located approximately 400 kilometres east of the cities of

Shanghai Shanghai (; , , Standard Mandarin pronunciation: ) is one of the four direct-administered municipalities of the People's Republic of China (PRC). The city is located on the southern estuary of the Yangtze River, with the Huangpu River flow ...

and

Ningbo Ningbo (; Ningbonese: ''gnin² poq⁷'' , Standard Mandarin pronunciation: ), formerly romanized as Ningpo, is a major sub-provincial city in northeast Zhejiang province, People's Republic of China. It comprises 6 urban districts, 2 sate ...

Zhejiang Zhejiang ( or , ; , also romanized as Chekiang) is an eastern, coastal province of the People's Republic of China. Its capital and largest city is Hangzhou, and other notable cities include Ningbo and Wenzhou. Zhejiang is bordered by Jiang ...

. The region is a repository for natural gas, and consists of the Chunxiao, Tianwaitian, Canxue, Duanqiao, and Pinghue fields. The entire trough is approximately 500 kilometres long, and runs parallel to the Chinese coast. On August 19, 2003, it was announced that

Sinopec China Petroleum & Chemical Corporation (中国石油化工股份有限公司) or Sinopec (), is a Chinese oil and gas enterprise based in Beijing. It is listed in Hong Kong and also trades in Shanghai. Sinopec Limited's parent, Sinopec Gr ...

CNOOC China National Offshore Oil Corporation, or CNOOC Group ( Chinese: 中国海洋石油总公司 Pinyin: ''Zhōngguó Háiyáng Shíyóu Zǒnggōngsī''), is one of the largest national oil companies in China, and the third-largest national oil ...

Royal Dutch/Shell Shell plc is a British multinational oil and gas company headquartered in London, England. Shell is a public limited company with a primary listing on the London Stock Exchange (LSE) and secondary listings on Euronext Amsterdam and the New Yor ...

and

Unocal Union Oil Company of California, and its holding company Unocal Corporation, together known as Unocal was a major petroleum explorer and marketer in the late 19th century, through the 20th century, and into the early 21st century. It was headqu ...

had entered into a joint venture to exploit the gas reserves in the trough, beginning in mid-2005. Gas production was expected to reach 2.5 km³ a year by 2007. However, on September 29, 2004, the two foreign partners in the joint venture, Royal Dutch/Shell and Unocal Corporation, announced their withdrawal citing doubts over the commercial viability of the resources in the area and the territorial dispute.

External links

Oil giants depart Xihu Trough gas project
''China Daily''. September 30, 2004. Landforms of China East China Sea {{PRChina-geo-stub