Hydraulic fractures: how far can they go?
14 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 to be discussed at an open meeting of the Geological Society on Monday (18th June).
The research, published earlier this year in the journal Marine and Petroleum Geology, suggests that a minimum distance of 600 metres should always 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, is speaking as part of an public briefing meeting at the Geological Society, which will bring 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 include Professor Peter Styles from Keele University, who will speak about induced seismicity, and Dr Robert Ward from the British Geological Survey, who will discuss the safe extraction of shale gas with regards to groundwater and well integrity.
Programme
10.30 Registration – tea and coffee
11.00 Introduction (Professor David Manning, Newcastle University)
11.10 What is shale gas, what is the likely UK resource and where is it? (Professor Mike Stephenson, British Geological Survey)
11.50 How is shale gas extracted? Hydraulic fracturing and directional drilling (Professor Richard Davies, Durham University)
12.30 Lunch
13.30 Can shale gas be extracted safely? (1) Induced seismicity (Professor Peter Styles, Keele University)
14.10 Can shale gas be extracted safely? (2) Groundwater, well integrity, use of water (Dr Rob Ward, British Geological Survey)
14.50 What is the regulatory framework for shale gas exploration and production? (Tony Grayling, Environment Agency)
15.30 General discussion and closing remarks
15.45 Tea and coffee