Gazprom says it has begun production at an Arctic oil rig raided in September by Greenpeace.
In an announcement in Moscow on Friday, the company said it also has rights to 29 other fields it intends to exploit in Russia's section of the Arctic seabed.
"Gazprom has begun oil production at the Prirazlomnoye deposit," the company said in a statement.
"This is the first project in Russia's history aimed at developing the resources of the Arctic shelf and the start of large-scale work by Gazprom that will create a major hydrocarbons production centre in the region."
Several Greenpeace personnel attempted to board the Prirazlomnaya platform on 18 September.
Security agents later boarded the icebreaker Arctic Sunrise and arrested the 30 people aboard.