The shale oil boom that catapulted the U.S. into being the world's largest oil producer may be going bust. Oil prices are dropping amid weakening demand, bankruptcies and layoffs are up, and drilling is down — signs of a crisis that's quietly roiling the industry.
Some of the most successful companies in the oil business are household names — think Exxon Mobil or Chevron. But the boom in shale drilling has been driven by smaller, independent operators. These companies have pushed the limits of drilling technology and taken big risks on unproven oil fields.