Here’s an entertaining and informative piece from the Register’s Andrew Orlowski on the new dash for shale gas:
Frack me! UK shale gas bonanza ‘bigger than North Sea oil’
Andrew Orlowski – Dec 14 2012
The shale gas will be collected using induced hydraulic fracturing, known as “fracking”, which splits rocks thousands of feet below ground using high-pressure liquid.
This is a defeat for environmentalist activists and the powerful renewables lobby – but they have a valuable consolation prize few have noticed. Under the proposed regulatory regime, during the fracking process any tremors that measure 0.5 or higher on the Richter scale may trigger an automatic halt to operations under a “traffic light” scheme outlined by the Lib Dem energy minister Ed Davey.
What does this mean? Well, tremors below magnitude 3.0 are considered to be barely noticeable, and bear in mind that the Richter scale is logarithmic: the energy released by a tremor of magnitude 0.5 is equivalent to the energy released by a large hand grenade.
But since the “epicentre” is thousands of feet below the surface, a 0.5 event escapes the detection of all but the most sensitive seismic monitoring equipment.
Yet one 0.5 event alone will be enough to halt fracking and it can only be restarted by the minister. Which, in practice, means it’s in the hand of the fanatically pro-wind Whitehall bureaucrats at the Department of Energy and Climate Change.
By contrast, the UK consortium Cuadrilla – which halted exploratory fracking near Blackpool in early 2011 after causing two minor earthquakes - uses the German safety standard, one of the world’s more conservative standards. This sets the maximum permissible tremor magnitude at 2.6 and recommends mitigation measures if seismic activity exceeds magnitude 1.7 – after which the drillers halt water injection and reduce the pressure on the shale.
Davey admitted that the 0.5 red-light threshold is “far below a perceptible surface event, but larger than the expected level generated by the fracturing of the rock”, which he considers “an appropriately precautionary approach”. But he admitted: “We received representations in our consultation that this is too cautious.”
Read the rest of the article at el Reg: