The shale revolution has profound implications for America’s role in the world and the global balance of power, but let us not get carried away. Oil experts noticed how many crews in the Bakken field were told to stand down when crude prices dipped earlier this summer. “Supposedly cheap shale turned out to be rather expensive shale in that, as soon as Brent fell to $90 per barrel, a large proportion of US shale oil in key regions seemed to lose all its rent,” said Paul Horsnell from Barclays Capital.