In 1996, the US shale industry comprised one operator and no-one had any idea that producing hydrocarbons directly from source rocks would one day have such an impact on both the US natural gas market and the world oil market — turning what was once the world’s largest importer of both commodities into a net exporter.

That one company was an independent named Mitchell Energy and its founder, George Mitchell, is credited with almost single-handedly discovering the concept of shale gas production through more than a decade of trial and error in the Barnett shale around Dallas-Fort Worth.