The British Geological Survey (BGS) and the Environment Agency (EA) have developed a method of assessing the vulnerability of groundwater from onshore oil and gas extraction activities in England.
According to the BGS, the new tool will improve understanding of the risk to groundwater but the organisation is seeking industry input to further develop the methodology.
The tool was developed following a study conducted by the BGA to create
an accessible and nationally consistent method for assessing the vulnerability of groundwater to potential contamination from any possible future activities deeper in the subsurface.
The method is based on well-established approaches already employed by the EA as part of the environmental regulation and permitting process.
The BGS said in a statement about the new tool: “The UK oil and gas industry is one of the most regulated in the world and so risks to groundwater are already covered in UK law. This new vulnerability assessment will ensure that the UK continues to put safety first when investigating new energy sources.”
The method uses the BGS’ 3D geological model of England to show the locations of aquifers and rocks which could contain oil and gas. This allows identification of the key parts of the underground water system that might be affected by future hydrocarbon extraction by considering factors such as the classification of the groundwater, the type of extraction processes, groundwater flow and the vulnerability of the groundwater.
“This method is a first step to understanding the risk to groundwater from these activities. It highlights the value and importance of 3D hydrogeological information for England,” said BGS director of groundwater science Rob Ward.
The method was trialled on five case study sites across England addressing different extraction activities; conventional oil and gas in southeast England, coal bed methane in the East and West Midlands, shale gas in northwest England and shale gas and conventional oil and gas in northeast England.
Most aquifers were rated as being at low risk from contamination. There were occasional instances of medium to low risk ratings for important aquifers with a smaller separation from the oil and gas sources. Medium/high risk groups occur rarely, where important aquifers overlie shale gas and coal bed methane activities. There are no potential receptors in the high risk group in the case studies.