Chevron Corp. and Exxon Mobil Corp. plan to significantly ramp up production in the oil field at the heart of the American fracking boom, the latest sign that the next era of shale drilling is likely to be led by the major oil companies. In the next five years, Chevron expects to more than double its production in the Permian Basin in Texas and New Mexico to 900,000 barrels of oil and gas a day, the company said at an investor event Tuesday. That is a nearly 40% increase from its previous forecast. …