A refinery went to the Chinese. A stake in a Siberian oil field went to BP. And a large regional oil company widely expected to be gobbled up by Rosneft , the Russian state oil giant, remained on the balance of a government agency instead. With a powerful ally of President Vladimir V. Putin at the helm, Rosneft has for more than a decade grown rapaciously inside Russia and abroad, as a company coming to symbolize the wealth and might of Russia during the oil boom. But that changed this year. Rosneft, though still the world’s largest publicly traded oil company when measured by production, has been unloading assets while struggling to pay down debt. “The government is really facing tough times,” said Ildar Davletshin, an energy analyst […]