Fracking earthquakes and flaming water: but not in the UK

● By Dr. Alan Herbert, University of Birmingham ● Energy and Climate Change Secretary, Ed Davey, reignited the row over fracking this week, when he insisted this method of extracting shale gas was no “great evil” and could act as a bridge to a “green future” in the UK so long as it was properly regulated. The UK is thought to have significant reserves of shale gas which the government has encouraged the industry to exploit as the gas reserves from the North Sea decline. Hydraulic fracturing, or fracking, is not new. It has been used to improve the permeability of rock around a well for many years in gas reservoirs where rocks are relatively impermeable. Fracking for shale gas differs only in scale, in that as the fractures are the only pathways for gas to move through the formation to the well, so they must be much more extensive. This is done by injecting a watery brine of chemicals and sand under high pressure into the rock to create fractures along the length of long horizontally-drilled wells off the main well. These are well-established techniques, but they are used more extensively when tackling shale gas reserves. What are the risks? Public concern has been raised by the two earthquakes in Blackpool and by health scare stories from the US where there has been evidence of water supply contamination and burning tapwater. Fracking by its nature breaks the rock, and this creates seismic events. However, extensive monitoring and experience from the US in particular has shown that the fracking is unlikely to lead to harmful seismicity. The Royal Society and Royal Academy of Engineering investigated these risks and concluded that there was no risk from seismicity associated with fracking from suitably located wells in the UK. The Blackpool earthquakes were at the upper end of the range of expected seismicity, caused no harm, and were due to fracking wells close to an existing fault. The second issue that causes alarm is the risk of pollution ...Zum vollständigen Artikel

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