* Hydrocarbon reserves rose 2.5 pct under PRMS
* Reserves replacement ratio 163 pct under PRMS
* Shares outperform broader market (Adds details)
MOSCOW, Feb 8 Rosneft (ROSN.MM) kept its grip firmly on the top spot among world's publicly traded oil companies as it reported on Monday a 2.5 percent rise in hydrocarbon reserves for 2009 under PRMS rules.
The state-controlled firm has been a chief driver behind Russia's recent surge in oil output, which last month remained above 10 million barrels per day, mainly thanks to Rosneft's huge newly commissioned Arctic Vankor field.
In January, Rosneft also announced the discovery of a new field in East Siberia, Sevastyanovo, that analysts said could potentially add 4 percent to Rosneft's proven and probable reserves, as the field's reserves are estimated at 150 million tonnes.
On Monday, Rosneft reported a 163 percent reserves replacement ratio under the Petroleum Resources Management System (PRMS) criteria in 2009.
Russia's largest oil company said in a statement its proved reserves under the PRMS methodology, formerly known as SPE, stood at 22.858 billion barrels of oil equivalent (boe), up 2.5 percent from 22.307 billion boe in 2008.
Under the more stringent U.S. Securities and Exchange Commission's (SEC) methodology, which takes into account reserves extractable during the life of companies' existing licences, Rosneft's reserves rose to 15.146 billion boe from 14.448 billion boe in 2008.
The reserves audit, performed by DeGolyer and MacNaughton, confirmed Rosneft was first among public oil companies in terms of oil reserves, under both PRMS and SEC standards.
Rosneft said its hydrocarbon reserve life was 26 years, 23 years for oil and 66 years for gas, under the PRMS rules.
Shares in Rosneft were up 1.05 percent on Russia's top MICEX bourse by 0830 GMT, outperforming the broader MICEX oil and gas index .MCXOG, which rose by 0.80 percent. (Reporting by Vladimir Soldatkin; Editing by Rupert Winchester)
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