''Kolskaya'' was a jack-up rig operating in the

Russian Far East The Russian Far East (russian: Дальний Восток России, r=Dal'niy Vostok Rossii, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in Northeast Asia. It is the easternmost part of Russia and the Asian continent; and is admini ...

. It was built by Rauma-Repola in

Pori ) , website www.pori.fi Pori (; sv, Björneborg ) is a city and municipality on the west coast of Finland. The city is located some from the Gulf of Bothnia, on the estuary of the Kokemäki River, west of Tampere, north of Turku and north-w ...

Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...

in 1985 and was owned by the Russian company ''ArktikmorNeftegazRazvedka'' (AMNGR), a subsidiary of

Zarubezhneft JSC Zarubezhneft (russian: Зарубежнефть) is a Russian state-controlled oil company based in Moscow that specializes in exploration, development and operation of oil and gas fields outside Russian territory. Sergei Kudryashov is the co ...

. ''Kolskaya'' was an independent leg cantilever type jack-up rig. It was long and wide, and could accommodate up to 102 people. Its rated water depth for operations was . Its drilling depth was .

Capsize and sinking

On December 18, 2011, the rig, which was under tow during a fierce storm,

capsized Capsizing or keeling over occurs when a boat or ship is rolled on its side or further by wave action, instability or wind force beyond the angle of positive static stability or it is upside down in the water. The act of recovering a vessel fro ...

and sank in the

Sea of Okhotsk The Sea of Okhotsk ( rus, Охо́тское мо́ре, Ohótskoye móre ; ja, オホーツク海, Ohōtsuku-kai) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands ...

. It was being towed by the icebreaker ''

Magadan Magadan ( rus, Магадан, p=məɡɐˈdan) is a port town and the administrative center of Magadan Oblast, Russia, located on the Sea of Okhotsk in Nagayev Bay (within Taui Bay) and serving as a gateway to the Kolyma region. History Maga ...

'' and the tugboat '' Neftegaz-55'' having just completed an exploration well for

Gazprom PJSC Gazprom ( rus, Газпром, , ɡɐzˈprom) is a Russian majority state-owned multinational energy corporation headquartered in the Lakhta Center in Saint Petersburg. As of 2019, with sales over $120 billion, it was ranked as the larges ...

off the

Kamchatka Peninsula The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and we ...

. The incident happened some off the coast of

Sakhalin Sakhalin ( rus, Сахали́н, r=Sakhalín, p=səxɐˈlʲin; ja, 樺太 ''Karafuto''; zh, c=, p=Kùyèdǎo, s=库页岛, t=庫頁島; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, ''Sahaliyan''; Orok: Бугата на̄, ''Bugata nā''; Nivkh: ...

island, in waters more than deep. In terms of operational safety, the towing operation's compliance with best practices was doubtful since the platform’s manufacturer explicitly stated that "towing is prohibited in the winter, in winter seasonal zones." A search and rescue effort began as soon as the rig sank and was halted five days later on December 22. Of the 67 people known to have been aboard ''Kolskaya'', 14 had been rescued and 36 more were listed as missing. Only 17 bodies had been recovered. With 53 declared missing or dead, it was the largest number of casualties in an accident the Russian oil sector has ever experienced.

References

{{Coord, 49, 31, , N, 148, 14, , E, display=title 1985 ships 2011 in Russia Disasters in the Russian Far East Jack-up rigs Maritime incidents in 2011 Maritime incidents in Russia Oil platform disasters Shipwrecks in the Sea of Okhotsk Shipwrecks of Russia Oil spills in Asia Water pollution in Russia