CHINA National Offshore Oil Corp, the nation's third-largest oil explorer, will postpone starting its first oil refinery until the end of the year, because some major natural disasters delayed equipment deliveries, two company officials said.

The snowstorms in January and February, the Sichuan earthquake in May and floods in the south this summer have affected the transportation of some facilities to the new plant, which is in Huizhou in Guangdong Province, said the officials.

CNOOC, parent company of Hong Kong-listed CNOOC Ltd, is diversifying from oil production to refining business by building the 240,000-barrel-a-day oil-processing plant.

The refinery was due to start trial operations in June, Bloomberg News said.

The facilities for the plant will be in place by the end of this month, said one of the officials, who is based in Beijing, where CNOOC has its headquarters.

The delay isn't "major" and construction is proceeding "smoothly", said the other official, who is based in Huizhou.

The refinery will source crude from CNOOC's Penglai oil field in the Bohai Bay.

CNOOC and Conoco°?Phillips have started operating a platform in the Penglai 19-3 oil field, off the coast of Shandong Province, the Chinese oil company said on September 16.

CNOOC has a 51-percent stake in the field while Conoco°?Phillips's China unit has a 49-percent share.