MOSCOW, Russia — It seems BP has turned to Russia to raise its fortunes.

Last week the British company announced a landmark agreement with Rosneft, Russia’s biggest oil firm, that will give BP access to Russian Arctic reserves previously off-limits to foreign companies.

The experience accrued by BP as a result of the 87-day oil leakage into the Gulf of Mexico last year was cited as a reason Rosneft chose the company as a partner in the biggest deal of its 18-year corporate history.

“One that’s been caned is worth two that haven’t,” said Prime Minister Vladimir Putin quoting a Russian proverb in a reference to the benefits of the oil spill for BP.

Rosneft and BP will work in partnership to explore the icy Kara Sea, an area on Russia’s Arctic continental shelf containing 5 billion tons of crude oil and 10 trillion cubic meters of gas, according to estimates.

Russia’s Arctic shelf is estimated to have enough oil to supply world demand for four years and is an increasingly attractive prospective for Russian oil companies looking to maintain production levels as traditional fields in western Siberia begin to run dry.

Scientists estimate that global warming will melt enough of the polar ice cap by 2025 to 2030 to open the Russian Northern Sea Route to commercial shipping, which is encouraging investment in the region now.

Domestic oil companies, however, do not have the experience to develop the offshore resources — their exploitation is dependent on the drilling expertise of international companies. Though the Kremlin is likely to work on a case-by-case basis, the BP-Rosneft deal is a first step, said Constantine Cherepanov, an analyst at UBS, “which could open the door to other international companies.”

Rosneft, which is controlled by the Kremlin, is also using BP as tool to spread the not inconsiderable economic and environmental risks. BP will receive only a one-third stake in the joint venture but it will front all the exploration costs, likely to be a significant sum.

“The deal allows Rosneft to let BP go first,” Cherepanov said.

There has been much criticism of the potential environmental impact of drilling in the sensitive Arctic region. A blow-out on the scale of what occurred on the Deepwater Horizon rig in the Gulf of Mexico would have catastrophic consequences in Arctic waters, which are frozen for most of the year.

There is no way of clearing oil from under several meters of ice and bacteria break down oil much slower in cold conditions, making environmental regeneration a much slower process. Vladimir Chuprov, the head of Russia’s Greenpeace energy unit, described Rosneft CEO Igor Sechin’s defense of Rosneft’s safety record as “black humor.”

The joint of intentions of Rosneft and BP in Russia’s Arctic, he added, carry “serious economic and ecological risks.”

The companies cemented their partnership with a share swap worth $8 billion. Rosneft will be the second largest BP shareholder while BP becomes Rosneft’s biggest private stakeholder. Rosneft absorbed the lion’s share of jailed tycoon Mikhail Khodorkovsky’s oil company Yukos when it was broken up by the state in 2006.

The tie-up with Rosneft is a gamble for Robert Dudley, BP’s CEO, said Chris Weafer, chief analyst at Uralsib. He said it makes BP a potential Western target for shareholders of Menatep, Khodorkovsky’s holding company, which is currently suing the Russian state for $98 billion in the European Court of Human Rights.

Markets, however, responded favorably to what BP described as a “groundbreaking global strategic partnership.”

“It is a win-win for both companies” said Vladimir Rusinov, an oil analyst at Renaissance Capital.

BP has gained access to new resources at a time when it is facing increasing difficulties in the United States following the spill, while Rosneft will receive the technology and experience it needs to implement offshore exploitation of the Arctic region.

The deal is also a coup for Rosneft as it will help fulfil President Eduard Khudainatov’s stated ambition to boost the company’s international presence.

Sechin, who is also a deputy prime minister of Russia, said, “Russian companies are quickly emerging at the forefront of the global energy industry.”

Today Russia and Jordan announced an agreement encouraging Russian companies to explore for oil and gas in the Arab country.

Claims to sovereignty in the mineral-rich Arctic have been have been the subject of diplomatic tension in recent years. Russian explorers planted a rust-proof flag two and a half miles below the North Pole on the Arctic sea floor in 2007.

There has been no comment on the deal from the Obama administration but U.S. Rep. Ed Markey (D-Mass.), ranking member of the House Natural Resources Committee, said BP should be re-named “Bolshoi Petroleum.” Citing risks to U.S. security from the Russian state owning a significant stake in a company that was the biggest oil supplier to the U.S. military in 2009, Markey called for a thorough examination of the deal.

While Britain’s energy minister Chris Huhne called the deal “good news,” there was also anger from some quarters in the U.K. Sir Menzies Campbell, the former leader of the Liberal Democrat Party now part of the coalition government, said there was an “inherent contradiction” in Britain’s support for the deal after the government expressed deep concern last month over a seven-year extension to Khodorkovsky’s sentence.

This is not the first time BP and Rosneft have collaborated. BP purchased $1 billion of Rosneft shares in the company’s 2006 London IPO and the two companies have been conducting joint explorations in the northern Pacific.

BP has the most Russian experience of all the oil majors — not all of it positive — through its venture with a group of Russian billionaires, TNK-BP. Dudley knows this better than most because, as TNK-BP CEO, he was obliged to leave Russia in 2009 during a bitter shareholder dispute.

TNK-BP has been placed in an ambiguous position by the deal with Rosneft.

A 2008 U.S. diplomatic cable published by Britain’s Guardian newspaper on Tuesday quoted the then-BP Vice President for Russia and Kazakhstan David Peattie saying that “in two to three years, BP expects that TNK-BP will be taken over by the Russian Government and split into separate oil and gas components that Rosneft and Gazprom will control.”

Alexander Eremin, an oil and gas analyst at Finam, said “TNK-BP is likely to join the Rosneft/BP alliance — otherwise there will be another shareholder conflict.”

