Rosneft held its top spot among the world's publicly traded oil companies in 2009 as it announced a 2.5% rise in hydrocarbon reserves, reports Reuters.
The audit has been conducted under the Petroleum Resources Management System (PRMS) and US Securities and Exchange Commission (SEC) criteria.
Rosneft has been a key contributor to Russia's rise in oil production after discovering a new field in Siberia with 150 million tonnes of estimated reserves, and recently commissioning the giant Arctic Vankor field.
The company's proved hydrocarbon reserves for 2009 increased by 2.5% to 22.858 billion barrels of oil equivalent (boe) compared with 22.307 billion boe in 2008 under PRMS standards.
Rosneft's proved oil reserves under PRMS rose by 2.1% in 2009 to 18,058 million barrels, while proved gas reserves rose by 4% to 28,801bcf.
Under PRMS, Rosneft's hydrocarbon reserve life was 26 years, 23 years for oil and 66 years for gas.
The company's proved hydrocarbon reserves increased to 15.146 billion boe in 2009 compared with 14.448 billion boe in 2008 under the SEC criteria, which includes reserves extractable during the life of companies' licences.
Under the SEC standards, Rosneft's proved oil reserves in 2009 stood at 13.931 million barrels, while proved gas reserves stood at 7.295bcf.