Tectonic activity may have scuppered UK fracking potential

The potential for recovering shale gas by fracking in the UK may have been overhyped, because the geological history of the region has been overlooked, Prof John Underhill, chief scientist at Heriot Watt's Institute of Petroleum Engineering has warned.

Plate tectonics and the effects of volcanism millions of years ago may have deformed the rocks in which hydrocarbon deposits form, prevent their formation in the first place or making them uneconomical to recover. This would mean that the debate over the environmental effects of fracking is a sideshow, said Underhill: “Both sides of the hydraulic fracturing debate assume that the geology is a ‘slam dunk’ and it will work if exploration drilling goes ahead. The inherent complexity of the sedimentary basins has not been fully appreciated or articulated and, as a result, the opportunity has been overhyped.

In the US and Eastern Europe, where shale gas is plentiful, deposits formed in the middle of continental plates. But this is not true of the UK, which is at the edge of a continental plate and its geology is, therefore, vulnerable to deformation by the effects of plate tectonics. The crucial event in this case, according to Prof Underhill, was the formation of the Atlantic Ocean 55 million years ago, accompanied by an upward surge of molten magma under Iceland. This surge tilted the rocks that now make up the UK and pushed the sedimentary basins where material had collected that would be turned into natural gas by the heat and pressure of overlying rocks against the stable geology of continental Europe.