Something is awry in the beleaguered U.S. shale patch: older wells, which normally gush oil or natural gas in their first few months before rapidly depleting, are not petering out as quickly as they should. When oil prices began falling a year and a half ago in the deepest rout in a generation, many analysts expected U.S. crude production, especially from fracking in the new shale plays that contributed to a global supply glut, to follow quickly. Producers, such as Continental Resources Inc ( CLR.N ) and Whiting Petroleum Corp ( WLL.N ), have slashed spending on almost everything, in some cases even leaving drilled wells unfinished to conserve cash and wait for a sustained turnaround in prices. With oilfield activity suddenly contracting, production from […]