Exxon Mobil Corp, whose oil field assets are being investigated by the U.S. government, warned on Friday it may need to slash proved reserves on its books by nearly 20 percent if oil prices stay low for the rest of 2016. The news pushed the company’s share price down 2.3 percent to $84.93 in afternoon trading, on an otherwise upbeat day that saw Exxon and Chevron post quarterly profits that beat Wall Street expectations. Results were helped by cost cutting, though refining margins narrowed from previous quarters. Exxon, as part of its reserves announcement, said it would perform an assessment of its major long-lived assets during its annual budgeting process, similar to one carried out in 2015. “Quantities that could be […]