As of December 31, 2007, Rosneft had net estimated proven reserves of 21.699 billion barrels of oil equivalent, including 17.513 billion barrels (2.399 billion metric tons) of oil and 25.116 trillion cubic feet (711 billion cubic meters) of natural gas.
Rosneft made the announcement on Monday following the results of an independent audit of its oil and gas reserves prepared by DeGolyer and MacNaughton.
Rosneft became Russia's largest crude producer after acquiring most of the assets of bankrupt oil firm Yukos through liquidation auctions in 2007.