Overseas investments by China's national oil companies in 2010 look as if they will outpace by far the $18.2 billion spent in 2009, with more than half that amount already committed by April, according to an International Energy Agency study issued Thursday.

From January 2009 to April 2010 alone, the three majors--China National Petroleum Corp., China Petrochemical Corp., or Sinopec, and China National Offshore Oil Corp.--spent around $29 billion worldwide to acquire oil and gas assets, the IEA said in its latest monthly oil markets report.

In addition to these direct investments, CNPC and Sinopec were involved in 11 loan-for-oil deals with eight countries worth $77 billion, and the companies entered contracts committing them to invest at least $18 billion in future exploration and development, mostly in Iraq and Iran, it noted.

China is now generating 40% of incremental global oil demand of 1.7 million barrels a day expected in 2010, and it will account for nearly 45% of 2010-15 growth.

"
China 's domestic oil production base faces the challenge of large mature assets, and with demand set to continue rising rapidly, China will remain reliant on the international oil market to meet incremental oil needs."

Earlier Thursday,
China 's General Administration of Customs said oil imports in the first five months of this year were 29% higher than year-earlier levels, at an average of 4.64 million barrels a day.

China 's oil companies last year accounted for 13% of total global oil and gas acquisitions in 2009.

The IEA data didn't include a number of more recent deals, such as CNPC's mid-May buy of a 35% stake in a unit of Royal Dutch Shell PLC (RDSB) in
Syria and Sinochem Group's $3 billion purchase of a 40% stake in Statoil ASA's (STO) Brazilian offshore Peregrino oilfield.

Chinese oil majors expanded their overseas oil equity share to 1.5 million barrels a day in the first quarter of 2010, from 1.1 million barrels a day of crude oil output in 2009, the energy watchdog said.

While those volumes were relatively limited, concerns exist that this activity is effectively "removing" oil from the market, it said.

"But the fungible nature of markets and the apparently market-oriented thinking behind the decisions suggest this is not the case."

China 's aggressive expansion overseas has been mirrored by growth in its domestic petrochemicals industry.

In the second half of 2009, it added three naphtha crackers totaling almost 2.3 million tons a year of capacity, and in 2010, three more--each with a capacity of 1 million tons a year--are due to come online, the IEA said.