ConocoPhillips and China's top offshore oil and gas producer CNOOC reached a preliminary agreement to pay the compensation through the Qinhuangdao city government in the northern province of Hebei, state-owned China National Radio said.

The oil spill at the Penglai 19-3 oilfield, China's biggest offshore oil field, which started in June 2011, has resulted in the release of about 700 barrels of oil, ConocoPhillips has said. The spill polluted more than 840 square kilometres of water, according to the State Oceanic Administration.

ConocoPhillips owns a 49 percent stake in the oilfield and acts as the operator, while the state-owned CNOOC has a 51 percent stake.

ConocoPhillips and CNOOC reached a settlement with the Chinese government in January to pay 1 billion yuan ($158.78 million) as compensation, and also to designate 100 million yuan ($15.88 million) of its previously announced environmental fund to be used to improve fishery resources in the region. ($1=6.2980 yuan) (reuters, Edited by Topco)