Concerns over shale gas drilling has led to calls for a moratorium on UK operations, but the company bringing the controversial technique to Britain says its methods are much safer than those coming under scrutiny in the US and such a ban is not needed.
Researchers at Manchester University’s Tyndall Centre this week released a report highlighting possible health risks associated with hydraulic fracturing or ‘fracking’, which uses chemicals and millions of gallons of water to release gas trapped deep underground.
As well as pointing out the environmental impact associated with the technique, the report drew attention to the lack of publicly available information on its safety and stressed that more research was needed.
The report was funded by the Co-operative, which offers green investment funds and is campaigning against the expansion of ‘toxic fuels’ such as oil from tar sands.
One of the key potential hazards the report identifies is the risk of ground- and surface-water contamination by gas and chemicals, based on evidence gathered from the US where tens of thousands of shale gas wells are now thought to exist.
What chemicals are actually injected into the ground is not publicly available information, the report says, but it identifies 58 out of 260 chemicals held in large quantities by shale gas operators in New York State that are potentially toxic, carcinogenic or mutagenic, which can alter DNA.
Between 15 and 80 per cent of the injected fluid returns to the surface as flowback, potentially bringing with it heavy metals, radioactive materials and hydrocarbons, the report says, and this would likely be seen as hazardous waste in the UK.
The report identifies multiple ways these chemicals could enter underground aquifers that provide drinking water, including through the wellbore should it lose integrity, through the fractures created in the ground or through natural cracks. Chemical spillage could also pollute land and surface water.
While shale gas production in the US has grown dramatically in the last decade, almost tripling between 2007 and 2009 according to government estimates, the technique is relatively new to Britain. Private company Cuadrilla Resources, founded in 2002, recently completed the first exploratory drilling in Lancashire.
But chief executive Mark Miller told The Engineer that while he would always welcome more research, a moratorium was unnecessary because the company was drawing on decades of personal experience from the US.
He said Cuadrilla had a substantial number of procedures and processes in place to prevent the examples of drilling problems mentioned in the report.
An impermeable ground layer was installed under the company’s site to protect against spillage, and fracking takes place 1,000ft below the estimated depth of the Sherwood aquifer in Lancashire to avoid potential contamination.
The drilling procedure uses a kind of mud to hold back the well’s pressure, as opposed to the faster method of air drilling that can lead to more problems with cementing the well.
An intermediate layer of well casing is installed between the top and bottom levels of the well to help keep it more securely sealed, as well as a safety valve that monitors pressure at the surface – a requirement in the UK but one that Miller said probably no company in the US uses for shale drilling.
‘Between the standard we’re setting right now that is being recognised by the government agencies and what’s already in place right now, I think things are in really good shape,’ said Miller.
‘Most of your land regulations here are really extracted from your offshore regulations and the North Sea safety regulations are indisputably the best in the world.’
Despite the decades of industrial experience and knowhow, one point that keeps re-emerging is the lack of information on the reports of associated health and environmental risks and how strong the link is with fracking.
Dr Andrew Aplin, a professor of petroleum geosciences at Newcastle University who has been involved in several industry-sponsored shale gas research projects, told The Engineer that while appropriate regulation was necessary to ensure good practice, it wasn’t obvious there was an inherent problem with fracking itself.
‘Yes there are reports of problems of contamination, obviously a very small fraction of the total wells that have been drilled,’ he said.
‘There have been some problems where aquifers have been contaminated, whether that be with gas or frack chemicals, but exactly how that water supply has been contaminated isn’t clear.’
This uncertainty even emerges from the documentary Gasland – released in the US last year and now distributed in the UK by the Co-operative – that investigates the effects of shale drilling on local communities.
Footage of one resident able to ignite the water in his tap due to its contamination with methane is being used to promote the film, but is itself subject to debate.
The Colorado Oil and Gas Conservation Commission (COGCC) ruled that this gas was biogenic (formed from decomposing matter in the ground). But Gasland’s writer/director Josh Fox has since responded that fracking can also disturb biogenic gas deposits and cause them to enter wells.