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Durham's Richard Davies speaks at Geological Society Briefing on fracking and hydraulic fractures
(21 June 2012)
The probability of hydraulic fractures, such as those produced in ‘fracking’ for shale gas, contaminating shallow aquifers is minimal, according to a study which was discussed at a recent open meeting of the Geological Society.
The research, published earlier this year in the journal Marine and Petroleum Geology, suggests that particularly for areas where fracking is being carried out for the first time a minimum distance of 600 metres should be maintained between the fracture zone and an aquifer. The maximum upward propagation of a stimulated hydraulic fracture which has been recorded is 588 metres, in the USA. Nevertheless, data presented in the study suggests that their probability of extending beyond 350 metres is around 1%.
With UK fracking typically occurring at distances of between two and three kilometres below the surface, the data suggests the risk of contamination to aquifers is minimal.
The paper’s lead author, Professor Richard Davies from Durham University, was speaking as part of an public briefing meeting held at the Geological Society on 18 June, which brought together a diverse audience of policy makers, members of industry, scientists and the public to discuss the potential for shale gas as a UK resource and its safe extraction. Other speakers included Professor Peter Styles from Keele University, who spoke about induced seismicity, and Dr Robert Ward from the British Geological Survey, who discussed the safe extraction of shale gas with regards to groundwater and well integrity.
A copy of the presentation and a video of the event is available via the link below.
Paper reference: Davies, R.J., et al., Hydraulic fractures: How far can they go?, Marine and Petroleum Geology (2012), doi:10.1016/j.marpetgeo.2012.04.001