China National Offshore Oil Corp, the country's biggest offshore oil explorer, plans a joint venture with Argentina's Bridas Energy Holdings, paying US$3.1 billion to take a 50 percent stake in a subsidiary, Bridas Corp, the company said yesterday.

Bridas Corp, currently wholly owned by Bridas Energy, will become equally owned by the partners and could have its name changed once the transaction is completed, CNOOC said in a statement to the Hong Kong stock exchange.

"Bridas, with a world-class oil and gas asset portfolio, is a very good beachhead for us to enter Latin America," said Yang Hua, CNOOC's president, in a separate statement.

Bridas Corp holds 40 percent of Pan American Energy, a hydrocarbons producer 60 percent controlled by UK-based oil major BP.

Bridas Corp had proven reserves of 636 million barrels of oil equivalent and an average daily production of 92,000 boe at the end of 2009, CNOOC said in its statement. The new joint venture company will have exploration and production activities in Argentina, Bolivia and Chile.

The partners expect to complete the deal in the first half of this year.

CNOOC has been a noticeable absentee from overseas M&A since it paid US$2.7 billion for a stake in French oil major Total's African Akpo field in 2006. A year earlier it was bumped by a United States political backlash from buying US-based oil company Unocal.

Recently, however, the company has been involved in several deals, including a possible partnership with London-based explorer Tullow Oil in an expansion of its interests in Uganda.

Last month CNOOC was also reported to be in negotiations with Iraq's oil ministry over the 2.5 billion barrel Maysan oil field.