Russia beat Saudi Arabia as China's top crude oil supplier in December 2015 for the fourth month in a row due to robust demand from independent Chinese refiners, which prefer shipments from the Far East over high-sulfur oil from the Middle East.

Russia strengthened its position in Asia by supplying nearly one-quarter more crude to the region in 2015, shifting the balance of power in one of the few bright spots in the global market and blunting the Organization of the Petroleum Exporting Countries' high-profile drive as to win customers.

China is one of the top targets for Russian oil after small, independent oil plants known as "teapots" won the right to import crude for the first time just several months ago. These plants were busy placing orders toward the end of 2015.

"These new plants were in a rush to use new quotas. But logistically they are not equipped to buy larger shipments from the Middle East or West Africa," said a Beijing-based official involved in marketing Middle Eastern oil. "Russian cargoes … suit them."

China's December imports from Russia hit a record of 4.81 million tons, or 1.13 million barrels per day (bpd), up 29 percent over a year earlier, according to Chinese customs data.

Imports from Saudi Arabia, the world's top exporter, were down 1.2 percent year-on-year during December at 1.05 million bpd.