Shale oil producers are throttling back so quickly on drilling that U.S. crude output could fall sooner than expected, within months, executives say as they slash costs to cope with tumbling crude prices and compete with Persian Gulf rivals. About a dozen chief executives who talked to Reuters or who spoke publicly, acknowledged they were taken aback by the scale and speed of the cutbacks, noting how this oil price downturn was different from several previous episodes in their careers. For one, companies are cutting costs deeper and faster than before as Wall Street investors increasingly place a premium on capital discipline rather than just production growth. Some also say the nature of shale makes it easier for companies to defer work and wait for prices to recover. The wells that drove the U.S. energy boom of the last decade rapidly deplete, so overall output will […]