UPDATE 2-China's state crude oil reserves at 31.97 mln T by start of 2016

(Adds analyst’s quote, estimate for state reserves stockpiling in fourth quarter)

BEIJING, Sept 2 (Reuters) - China increased its strategic crude oil reserves by 22.5 percent between the middle of last year and the start of 2016, taking the total to 31.97 million tonnes (233 million barrels), the National Statistical Bureau said on Friday.

The volume, equivalent to about 33 days of net oil imports to China, was higher than analysts had estimated.

“Stockpiling over the second half of 2015 was faster than our calculation,” Sengyick Tee of SIA Energy said. “The numbers look like more till the first quarter, mostly likely also including stockpiling by some independents.”

In its last update in December 2015, the government said it had 26.1 million tonnes, or about 190.5 million barrels, stockpiled by mid-2015.

The world’s largest consumer bought the crude as global prices sank 40 percent in the second half of 2015 to below $40 per barrel, testing fresh multi-year lows on evidence of a growing worldwide glut.

The reserve is closely watched by analysts as a gauge of what proportion of China’s oil imports is going into the reserves and how much is being refined and consumed.

Stockpiling should pick up significantly in the fourth quarter, but slower oil demand and some delays in preparing storage tanks will likely drag on the growth rate, according to Michal Meidan of Energy Aspect.

The current data includes strategic and some commercial stockpiles, the statistic bureau said. The government did not release a breakdown of the figure.

Reuters reported that a private company has signed a preliminary agreement to provide oil storage for 2.6 million barrels of commercial state crude reserves.

China intends to build crude reserves of 550 million barrels by 2020. (Reporting by Beijing monitoring desk; Editing by Christian Schmollinger/Ruth Pitchford)