The debt that fueled the U.S. shale boom now threatens to be its undoing. Drillers are devoting more revenue than ever to interest payments. In one example, Continental Resources Inc., the company credited with making North Dakota’s Bakken Shale one of the biggest oil-producing regions in the world, spent almost as much as Exxon Mobil Corp., a company 20 times its size. The burden is becoming heavier after oil prices fell 43 percent in the past year. Interest payments are eating up more than 10 percent of revenue for 27 of the 62 drillers in the Bloomberg Intelligence North America Independent Exploration and Production Index, up from a dozen a year ago. Drillers’ debt ballooned to $235 billion at the end of the first quarter, a 16 percent increase in the past year, even as revenue shrank. “The question is, how long do they have that they can get […]