BP says second-quarter refining margins drop to 6-year low Downstream business was key last year in cushioning cheap oil If Big Oil was a two-engine airplane, you could say it’s been flying on a single engine since energy prices crashed in 2014. Now, the second motor is sputtering. The major integrated oil companies, including Exxon Mobil Corp., Total SA and BP Plc, have relied on their so-called downstream businesses, which include refining crude into gasoline, oil trading and gas stations, to cushion the losses on their upstream units, which pump crude and natural gas. “The crash in oil prices in late 2014 brought refineries worldwide a pleasant surprise: booming margins,” said Amrita Sen, chief oil analyst at consulting firm Energy Aspects Ltd. in London. “But now, the market is changing.” BP, the first major to report second-quarter results, showed the impact on Tuesday. The British company said its downstream […]