The board of U.K. energy company BP PLC has struck a deal to swap its troublesome Russian oil venture TNK-BP for a big stake in Rosneft, the Kremlin-controlled energy company, a person familiar with the matter said Sunday.

The person said that the sale of BP's half of TNK-BP was expected to net the company between $10 to $15 billion in cash as well as a 15 to 20 percent stake in Rosneft, Russia's largest producer of oil. The person said that the ranges were approximate because the parameters of the deal were still being worked out. He spoke on condition of anonymity before an official announcement which he said the companies hoped to make "soon."

Such a deal would allow BP to exit its contentious partnership with the consortium of billionaires which controls the other half of TNK-BP while keeping a presence in Russia, a country responsible for producing nearly 10 million barrels of crude every day. BP sees the Russian market — in particular the vast reserves of oil thought to lie beneath the Arctic Ocean — as key to its recovery from the Gulf of Mexico oil rig explosion, a deadly disaster which led to the United States' worst-ever offshore spill.

The TNK-BP venture has been lucrative, paying out around $19 billion in dividends since it was set up in 2003, but the company has periodically been shaken by outbursts of open hostility between the London-based BP and its Russian shareholders. In 2008, relations deteriorated to such a point that Bob Dudley — then-chief executive of TNK-BP, now chief executive of BP itself — had to flee Moscow after what his company described as a campaign of harassment.

Jettisoning the consortium might bring a measure of stability to BP's operations in Russia, but the deal would also draw the British company much closer to the Kremlin; Rosneft is run by former deputy prime minister Igor Sechin, a longtime aide to Russian President Vladimir Putin, and BP's shareholders may worry about the political dimensions of the deal.

Britain's The Sunday Telegraph said that five of BP's leading investors, which it didn't identify by name, had qualms about the move.

It's not clear what, if any, action the consortium, known as Alfa-Access-Renova or AAR, plans to take in response to the move. An email listed on the group's website was invalid, and other contact details couldn't immediately be located. A previous deal involving Rosneft and BP — announced last year to massive fanfare — had to be shelved after AAR sued to stop it.

Rosneft declined to comment when reached by phone late Sunday. BP said it would not be making an official statement.


Nataliya Vasilyeva in Moscow contributed to this report.