Ukraine has stepped up its attacks on Russian refineries and oil infrastructure, which is bullish for crude prices as it curbs Russian crude exports and tightens global oil supplies. Ukraine attacked Russia's Salavat and Volograd oil refineries on Thursday, halting around 300,000 bpd of refining capacity. On Tuesday, Russia's Transneft Pipeline, which handles more than 80% of the country's oil, restricted the ability to store crude. Also, the Kirishi refinery, one of Russia's biggest refineries that has an ...