Under increasing pressure from competitors & the authorities, the Russian gas major is stepping up exploration & drilling in Arctic waters. A total of four wells were drilled and 3000 square km of 3D seismic mapping was conducted in the years 2011-2012 resulting in an increase in offshore reserves with more than 200 million tons of oil equivalents. The exploration was conducted in the waters surrounding the Yamal Peninsula, the Tazov Bay, as well as in the west Kamchatka and Sakhalin parts of the Okhotsk Sea, the 'Barents Observer' reports, citing a Gazprom press release.