The CEO of CNOOC Ltd., a big state-owned Chinese oil company, on Tuesday sought to dispel fears that oil-thirsty China is seeking to lock down global resources for its exclusive use.

"There seems to be a misconception about our overseas acquisitions and investments," said CEO Fanrong Li at a major energy conference here.

CNOOC recently completed the $15.1 billion purchase of the Canadian multinational company Nexen, which has holdings in the oil sands, the Gulf of Mexico and elsewhere.

The deal raised some eyebrows on Capitol Hill, although it was nothing like the Capitol Hill fury over CNOOC's 2005 bid for the U.S. company Unocal, which CNOOC eventually dropped (Chevron bought Unocal instead).

Li said the Chinese companies are commercial participants in the oil-and-gas market, noting China is not seeking to "hold each barrel" of oil it develops.

"This notion does not make any commercial sense," Li said at the IHS CERAWeek conference. "We sell our products at [the] best available distribution systems to maximize commercial value."

"Chinese oil companies are active participants in both [the] demand and supply side of the oil market," he said.

The Nexen deal was China's largest overseas acquisition to date, according to the U.S. Energy Information Administration (EIA). But there have been many others.

Since 2009 China's national oil-and-gas companies have purchased assets in the Middle East, North America, Latin America, Africa, and Asia, according to EIA.