At some plants, repairs designed to take a few days are deliberately stretched over weeks, the agency's sources said, because the facilities are often attacked again just as restoration nears completion.
Spare parts for complex secondary refining units were previously bought in the West. Their Russian and Chinese replacements now take months to arrive, Bloomberg's sources said.
The Ryazan refinery, which supplies fuel to Moscow, has stood idle for more than half the time since May, according to damage assessments seen by Bloomberg. The Tuapse plant has not operated since April. The Syzran facility spent six months either idle or running at less than a third of capacity, the agency writes.
Rosneft has 12 refineries in total, accounting for about a third of Russia's refining capacity. According to the company's reporting, it refined 35.5 million tonnes of oil in the first half of the year, down from 38.7 million tonnes a year earlier - a decline of 8%. Rosneft attributes the drop to "repair and restoration work."
Rosneft's net profit fell 18.4% in the first half, to 200 billion rubles. The company cites non-cash and one-off factors, including exchange-rate differences and asset impairment. EBITDA, meanwhile, rose 23%. The ratio of net debt to EBITDA stood at 1.8 - the highest in at least five years, according to Bloomberg's calculations.
Three Qatari officials told Bloomberg that the company's co-owner, Qatar's sovereign wealth fund QIA, which holds 18.46%, is watching the situation at Rosneft closely.
Rosneft's main new project, Vostok Oil on the Taymyr Peninsula, was conceived as a new Russian oil province, Bloomberg notes. In September, Putin gave the start to shipments from the project, in which Rosneft chief Igor Sechin has estimated investment at 4 trillion rubles.
Sechin promised to supply 50 million tonnes of oil a year from Vostok Oil by 2030 - about 1 million barrels per day, Bloomberg writes. But for now the new pipeline and terminal are carrying mainly oil from Vankor, which has been produced since 2009, while the new fields accounted for less than 5% of the flow before the launch.
The consultancy Rystad Energy expects the project to produce 440,000 barrels per day by 2030, less than half of what was promised. Only 80,000 of those barrels will come from the new fields.
Since the start of the year, Ukrainian drones have attacked Russian refineries at least 114 times, twice as often as in the same period last year, according to Bloomberg's count. In September, five of 15 confirmed strikes hit large Rosneft plants.
The United States is trying to halt the strikes on Russian refineries. On October 9, Trump announced after a conversation with Putin that sanctions on Russian diesel would be lifted, and on October 11 he wrote of an "immediate" energy truce that both sides had supposedly agreed to.
The Kremlin has not confirmed its agreement: Putin's press secretary, Dmitry Peskov, said only that "contacts are continuing." Overnight on October 15, Ukrainian drones again attacked the Ryazan refinery. The same day, Volodymyr Zelensky told the FT that the restriction on strikes on refineries had been lifted.