CHINA National Petroleum Corp, China Petrochemical Corp and two other Chinese companies will bid for oil and gas exploration rights in southeast Iraq as energy demand rises in the world's fastest-growing economy.

The two parents of PetroChina Co and China Petroleum & Chemical Corp, as well as China National Offshore Oil Corp and Sinochem Corp, have started to assess fields in Iraq, Zeng Xingqiu, Sinochem's chief geologist, told Bloomberg News yesterday.

China, which relies on imports for about half of its crude-oil needs, is seeking investment in overseas petroleum fields to satisfy growing energy demand from an economy that expanded 10.6 percent in the first quarter.

"Sinochem has completed evaluating 10 small fields in southeast Iraq," Zeng said. "The biggest risk is political uncertainty in that region. It's difficult to predict when we can produce oil from the fields."

The four Chinese companies are among 41 globally that have been allowed by the Iraqi government to bid for exploration rights, he said.