Sibneft's oil and gas reserves proven in accordance with the methods of the Society of Petroleum Engineers (SPE) reached, in 2003, 4.779 billion barrels of oil equivalent (642.7 million tonnes), according to the oil company's press release.
"The effective investment programme pursued by Sibneft allowed to preserve the reserves and boost output considerably in 2003," said Sibneft President Yevgeny Shvidler.
The audit was conducted by the U.S.-based Miller & Lents company.
The recoverable oil reserves were estimated at 4.623 billion barrels (621 million tonnes) compared to 4.575 billion barrels (615.3 million tonnes) as of January 1, 2003. The gas reserves grew from 24.3 billion cubic metres to 26.6 billion cubic metres.
"The audit of Sibneft's reserves conducted by Miller & Lents in accordance with the U.S. Securities and Exchange Commission's (SEC) standards revealed a more dramatic growth: the proven oil and gas reserves had gone up to 2.453 billion barrels of oil equivalent (329.9 million tonnes) from 2.197 billion barrels (295.4 million tonnes) last year. The company has a total of 2.368 billion barrels (318.4 million tonnes) of recoverable oil reserves and 14.5 billion cubic metres of gas," reads the press release.
The company explained that an increase in the reserves estimated according to the SEC methods was partly due to extended licenses on certain oil and gas fields. The licenses for the Sugutskoye, Zapadno-Noyabrskoye, and Sredne-Iturskoye fields were extended to 2050, while their original expiry date was 2013-2014.