Russian oil companies are facing difficulties repairing oil refineries built with the help of American and European engineering companies, reports Reuters. According to sources in the industry, the problems are exacerbated by Ukrainian drone attacks, which have struck at least a dozen Russian refineries this year. According to Reuters’ calculations, these attacks forced Russian refineries to shut down about 14% of their capacity in the first quarter. “If the stream of drones continues at this rate and Russian air defenses don’t improve, Ukraine will be able to cut Russian refining runs quicker…