The risk of causing man-made earthquakes by fracking could be greatly reduced if the high-pressure fluid injections used in the process are situated far enough away from geological faults. These are the findings of Durham University researchers.
The risk of inducing earthquakes by fracking for gas could be reduced if injection points in boreholes are situated at least 895 metres away from geological faults.
These are the findings of new research that used microseismic data to estimate how far fracking-induced fractures in rock extended horizontally from injection points.
The results showed a one per cent chance that these fractures could extend horizontally beyond 895 metres in shale rocks.
Fracking – or hydraulic fracturing – is a process in which rocks are deliberately fractured to release oil or gas by injecting highly pressurized fluid into a borehole.
In 2011, tremors in Blackpool in the UK were caused when injected fluid used in the fracking process reached a previously unknown geological fault.
Fracking is now recommencing onshore in the UK after it was halted because of fracking-induced earthquakes.
Research lead author Miles Wilson, a PhD student at Durham University, commented in a statement: “Induced earthquakes can sometimes occur if fracking fluids reach geological faults.
“Induced earthquakes can be a problem and, if they are large enough, could damage buildings and put the public’s safety at risk.”
The results, which were published in the journal Geomechanics and Geophysics for Geo-Energy and Geo-Resources, were based on data from 109 fracking operations carried out predominantly in the USA.
The latest findings go further than a 2017 study, which recommended a maximum distance of 433 metres between horizontal boreholes and geological faults.
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