The shale boom that made the U.S. the world’s top oil producer is nearing a crucial turning point

The U.S. shale boom is running out of steam, making Venezuela’s vast reserves look attractive to some U.S. oil companies. - MarketWatch/Rystad ShaleWellCube, iStockphoto The shale-oil revolution that transformed the U.S. into the world’s top oil producer is entering a new phase — one that could see America’s hard-fought lead in energy erode in fewer than five years as oil production growth peters out. The issue is a simple one. Shale well output declines rapidly. On average, a well produces roughly 80% o ...