MILAN/MOSCOW (Reuters) - Italy's biggest utility Enel
The deal has increased tensions between Russia's oil barons, a headache for Russian President Vladimir Putin as he looks to boost the fortunes of the economically significant energy sector.
It has also boosted the clout of Rosneft chief Igor Sechin, a long-standing ally of Putin.
The agreement had been announced on September 24, angering one of the stakeholders in SeverEnergia, Gennady Timchenko, a co-owner of Russia's second-largest gas producers Novatek
"It would have been probably appropriate if we had held talks with Rosneft before they announced their agreements with the Italians," Timchenko said last month.
Potentially one of Russia's largest part foreign-owned gas projects, SeverEnergia is expected to produce 36 billion cubic meters of gas and liquids by 2017.
It is a joint venture between Yamal Development and Arctic Russia BV. Yamal Development is jointly owned by Gazprom Neft and Novatek, and Arctic Russia BV was controlled by Enel and Italian peer Eni
Sources in the companies have said Novatek and Gazprom Neft were interested in Eni stake as well, while bankers have told Reuters Eni is considering selling its stake in SeverEnergia.
The sale is part of Enel's plan to sell 6 billion euros ($8.1 billion) worth of assets by the end of 2014 to cut debt and hang on to its investment-grade credit rating.
Enel recently said it would be able to beat its net debt target for 2013 if it managed to close deals announced so far this year before the end of December. Its shares were up 0.7 pct at 3.334 euros by 0913 GMT, not far from a two-year high of 3.358 set on Monday.
Rosneft became the world's top listed oil producer after the $55 billion acquisition of Anglo-Russian oil firm TNK-BP in March. Its oil output accounts for over 40 percent of the total in Russia, the global leader in crude production.
The growing influence of the state on the oil and gas sector has been questioned by some analysts, who argue it kills off competition and inflates costs.
Rosneft has ambitious plans to raise its output to 100 billion cubic meters of gas by 2020 and plans to build a liquefied natural gas plant (LNG) jointly with ExxonMibil
A source close to Novatek said the SeverEnergia assets had been seen as of great importance to the company and would have fitted with its Yamal project to produce LNG jointly with France's Total
The source also said Rosneft topped Novatek's initial $1.4 billion bid for the Enel stake, while Timchenko has said Rosneft'a acquisition came as a surprise to him.
A spokesman for Gunvor has denied any rifts between Timchenko and Sechin.
Gazprom Neft and Novatek declined comment.
(Reporting by Stephen Jewkes in Milan and Vladimir Soldatkin in Moscow; Editing by Francesca Landini and David Holmes)