MOSCOW (Reuters) - Rosneft is selling its three southern oil assets and could complete deals for all three by the end of May, sources told Reuters on Wednesday, as Russia’s top oil company shifts focus to the giant northern Vostok Oil project. Vostok Oil, in which global commodities trader Trafigura has a 10% stake, is one of Russia’s biggest oil projects, comparable in size with the exploration of West Siberia in the 1970s or the U.S. Bakken oil province over the past decade. Rosneft was selling its southern Stavropolneftegaz, Ingushneft and Dagneft with combined oil output of about 1 million tonnes per year, a fraction of the 205 million tonnes it pumped in 2020 (4.1 million barrels per day), four industry sources familiar with talks said. Cengeo, a private Russian company which focuses on mature oil fields, has already bought a 51% stake in Ingushneft and was expected to buy Stavropolneftegaz and Dagneft by the end of May, two sources said. Rosneft and Cengeo did not respond to requests for comment from Reuters. Rosneft has previously estimated that Vostok Oil, which will start production later this decade, would require more than 10 trillion roubles ($135 billion) in investments. After a call with Rosneft, several analysts had said last year Rosneft planned to sell some ‘brownfields’, or mature assets, in southern Russia, along with underperforming brownfields elsewhere, to raise capital to develop Vostok Oil. Crude oil from Stavropolneftegaz, Ingushneft and Dagneft is exported via Caspian Pipeline Consortium (CPC) system, in which Rosneft holds a minority stake. CPC pipeline ships Kazakh and Russian oil to the Black Sea. After the sale, Rosneft is expected to keep exports of gas condensate via CPC at least until the end of 2021, sources said. A joint venture between Rosneft and Royal Dutch Shell owns a 7.5% stake in CPC and there are no plans to sell it for now, sources added. CPC declined to comment. ($1 = 74.0100 roubles)