"We have bought out Oman's share - the entire 7%. Now only the technical details remain," Nikolai Tokarev said, adding that documents from Oman should be received and the legal procedures completed.
Another buyer for Oman's share was Kazakhstan, which holds 19% in the CPC. Russia's share is now 31% Russian business daily Kommersant said on Wednesday.
Russian Prime Minister Vladimir Putin first hinted that a deal might go ahead at a meeting with Kazakh President Nursultan Nazarbayev last Thursday.
In an interview with Kommersant, a source in Transneft, the operator of the Caspian Pipeline Consortium (CPC), confirmed that the deal had been completed, but did not disclose any details.
Oman agreed to sell its stake in the project early this year, Kommersant said. The country had sent relevant offers to Russia and Kazakhstan. Hungary's MOL was also a potential bidder.
Russia agreed to buy the entire 7% stake for $700 million, the price offered by the Hungarians.
However, a Kommersant source close to the deal said the final price was around $350 million - half the starting price.
The CPC, designed to carry Kazakh and Russian crude to a terminal on the Black Sea, was commissioned in October 2001. Its capacity currently stands at around 30 million metric tons of oil per year and is expected to double by 2012.
Mikhail Barkov, Transneft's vice president, said in late September he was not ruling out the possibility that the international consortium could be forced to close down.
He said the agreements on privileged tariffs for the consortium were set to expire at the end of 2008, putting into question the pipeline's future existence.