The U.S. may have even more—and much cheaper to get—supplies of natural gas than anyone imagined. The trick is applying supersize versions of the horizontal-drilling and fracking techniques that worked successfully elsewhere to an area that hasn’t seen this approach yet. The gains come from extending the lateral portions of wells by thousands of feet and pumping them full of enormous volumes of sand, chemicals and water to flush out more hydrocarbons. So far, the impressive results have been confined to a small area in a single Louisiana parish near the Texas border. But if the approach works across the giant Haynesville Shale, which spans 120 miles across both states, the era of low American gas prices could extend for decades into the future, experts say. “There’s a large likelihood that the United States will be enjoying very low gas prices for a very long time, maybe 20 years,” […]