Fracking ‘n’ leaking: UK scientists cite pollution fears due to insecure well barriers
The research by Durham University draws attention to a number of concerns with the British government’s plans to expand the exploitation of shale gas across the UK.
Fracking is a technique used to extract shale gas trapped deep underground. In order to release the gas, chemicals are blasted at high pressure into fissures in the rock. The practice was discontinued in the UK back in 2011 after a number of small earthquakes close to the northern city of Blackpool were found to be linked to fracking.
The British government is now championing fracking as an answer to rising gas and energy prices, but researchers have urged caution, citing previous cases when mass exploitation has resulted in pollution.
“It is likely that well barrier failure will occur in a small number of wells and this could in some instances lead to some form of environmental contamination,” warned the study, which was published in the journal Marine and Petroleum Geology.
As there are no currently operational shale gas fracking wells in the UK, the study looked at 8,030 wells in Pennsylvania and found that 6.3 percent of them (506) had experienced barrier failures between 2005 and 2013. This resulted in surface water contamination, land spills and problems with site restoration.
"Measurable concentrations of gas were present at the surface for most wells with casing or cementing violations," the researchers wrote, also warning that shale gas exploration in the UK could lead to water contamination because the wells could leak underground.
The failure of protective casing is not just particular to gas fracking – it occurs in most hydrocarbon extraction facilities. To investigate this, researchers examined available data from 143 onshore wells in the UK and found that between 2000 and 2012 nine pollution incidents were registered involving the release of crude oil.
However, researchers were unable to find data for more than 2,000 inactive wells because many had been abandoned or sealed. These so-called “orphaned” wells were left by their operators who went out of business, effectively nullifying their legal responsibility for the well.
"If those wells were to leak, the question is: Who is responsible? We don't know; it's not clear," Professor Richard Davies of Durham University, who led the study, told BBC News.
The study says that the environmental impact of oil and gas fracking in the UK may have been grossly underestimated because of the lack of publicly available information.
"In the UK, wells are monitored by well inspectors but there is no information in the public domain, so we don't really know the full extent of well failures. There were unknowns we couldn't get to the bottom of,” Davies told The Guardian.
Fracking companies have already begun test drilling in the UK, prompting a strong reaction from British communities who oppose the controversial extraction technique. Earlier this month, hundreds of protesters marched through the northern city of Manchester, calling for an end to test drilling in the area. Northwest England has been earmarked for fracking as the British Geological Survey estimates that the region may hold up to 1,300 trillion cubic feet of shale gas, which could meet the UK’s energy demands for the next six years.