* Rosneft currently supplies China with over 15 mln t/yr (Adds detail, quote, clarifies 31 mln tonnes are additional supplies)
MOSCOW, March 22 Russia's top oil producer Rosneft will, over time, more than triple total volumes of oil supplies to China, making the country Russia's biggest oil consumer, Rosneft head Igor Sechin said on Friday.
Russia will increase oil supplies by 31 million tonnes a year, and will get a $2 billion 25-year loan.
"Today we signed... an agreement on principles of crude oil supplies, which foresees (a) gradual increase in ... supplies starting from 800,000 tonnes this year in addition to those contracts and obligations that we signed in 2009," Sechin told reporters.
This will bring total Rosneft supplies to China to 45-50 million tonnes a year, though the time horizon remained unclear.
Rosneft currently supplies China with 15 million tonnes of oil a year (300,000 barrels per day) via the East Siberia-Pacific Ocean pipeline. Some volumes are also shipped via Pacific port of Kozmino.
Sechin also said that Rosneft and China National Petroleum Corporation (CNPC) agreed to jointly develop three offshore blocks in the Barents Sea and 8 onshore deposits in East Siberia.
Earlier on Friday, Sechin said that the goal of increasing oil supplies to China to 50 million tonnes a year (1 million barrels per day) was achievable.
(Reporting by Alexei Anishchuk; writing by Vladimir Soldatkin; Editing by Maya Dyakina and Jane Merriman)