Output in China's northern Bohai Bay, its largest offshore oil and gas production base, has been affected by icy conditions, China National Offshore Oil Corp (CNOOC) said.

Temperatures in the country have plunged to their lowest in almost three decades, cold enough to freeze coastal waters and trap 1,000 ships in ice, official media said at the weekend.

Large amounts of water in the Bohai Bay area have frozen, forming a layer of ice up to 15 cm thick, CNOOC, parent of CNOOC Ltd, said on its website (www.cnooc.com.cn).

The firm has deployed 13 icebreakers, installed radar and employed people to monitor conditions to ensure safe oil and gas production, it said.

Icy conditions have hit the producing areas of the Jinzhou 9-3 oilfield and the Jinzhou 20-2 gas field. Ice breakers are operating in several other oilfields such as Jinzhou 25-1, Jinzhou 25-1 South and Suizhong 36-1, CNOOC said.

State authorities have forecast that icy conditions in Bohai Bay will peak from early January to early February, it added. A spokesman for CNOOC was not immediately available for comment.

Oil and gas production in the Bohai Bay area topped 30 million cubic metres in 2012, the company said last month, although there were no new fields that came on stream in Bohai and the biggest offshore oilfield, Penglai 19-3, remained shut down after a series of oil spills in 2011.

(HK Edition 01/08/2013 page2)