China's strategic petroleum reserve (SPR) capacity is expected to reach 85 million tons, equaling 90 days of net imports by 2020, the China Economic Weekly reported Monday.

China's crude oil imports rose 19.8 percent year-on-year to 218 million tons in the first 11 months of 2010, meaning 55 percent of the country's oil is from abroad, according to the National Development and Reform Commission.

Meanwhile, statistics from Customs show that China's monthly oil imports were around 20 million tons in the first half of 2010.

Such massive oil imports trigger public assumption that the country is stepping up its SPR projects.

China started to fill its first phase SPR projects in 2007 and oil reserved in the projects could supply the national oil consumption for 13 to 14 days by 2009. Oil imported to SPR bases in the first phase cost $58 per barrel, according to the magazine.

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The second phase of SPR, with a designed capacity of 26.8 million cubic meters, were partly completed or under construction in 2009. Meanwhile, commercial reserve capacity at oil enterprises came to 300 million barrels, with the country's major oil firms Sinopec and CNPC accounting for 50 percent and 40 percent, respectively.

China is now planning the third phase of its SPR projects, which is expected to finish in 2020. The country's overall oil reserve capacity is estimated to equal 100 days of net imports, with SPR capacity equaling 90 days of net imports, which is the threshold set by the International Energy Agency.

China's oil reserve system can be divided into four grades, SPR, oil reserve at local governments, commercial reserve at State-owned oil companies, and other medium- and small sized oil companies, according to the report.

The report said that criteria for the country's oil reserve bases are: convenient transportation, proximity to refinery plants, and easy access to consumers.