China’s top offshore oil and gas producer, CNOOC Ltd., will begin operations this year at a gas field in the East China Sea despite a territorial dispute with Japan. ..CNOOC Chairman Fu Chengyu told reporters on Tuesday he expected the Chunxiao field, located south of Japan, to begin operations in August and September... ....On Monday Japanese media reported Japan had demanded that China halt construction at the Chunxiao natural gas field. Hydrocarbon deposits were found in the early 1970s... In 2004 China’s construction of the Chunxiao natural gas production plant 5 kilometres (3 miles) from the disputed area aggravated tensions...