Test to check water supply for gas leaks

A test to check for contamination of drinking water from gas extraction processes is being developed.

The move could help monitor the safety of unconventional techniques, such as shale gas and coal bed methane extraction, which have sparked debate owing to perceived health risks.

Methods used for shale gas extraction include hydraulic fracturing, commonly known as fracking, in which shale rocks below ground are split with high-pressure fluids to release gas that is recovered for fuel.

Coal bed methane is extracted from deep coal seams by drilling into the coal to reduce the pressure and release gas.

Health concerns

The need for such a test was highlighted following allegations in the US that, owing to fracking operations, drinking water has become contaminated with large amounts of methane from deep below ground.

Groundwater often contains methane gas from shallow natural sources, which is harmless in small quantities.

Researchers are developing ways to fingerprint methane gas by identifying the types of carbon and hydrogen present along with tiny traces of inactive natural gases, known as noble gases.

These fingerprints vary depending on the origin and depth of the methane, and will enable scientists to pinpoint its source.

Fingerprinting sites

The researchers, from the Universities of Edinburgh and Glasgow and the Scottish Universities Environmental Research Centre, will record the fingerprints of natural shallow methane in the groundwater at gas extraction sites before any commercial operations begin.

They will also take the fingerprints of deep methane produced by gas exploration.

If, following exploration activities, levels of methane in groundwater are found to have changed, the components of the gas present can be compared with the fingerprint analysis, to determine its origin.

If the gas is traced to gas exploration or extraction, appropriate action can be taken.

Scientists will develop the test by adapting a technique developed for use in monitoring potential leaks of carbon dioxide gas from storage sites deep underground.

The project will be supported by the Natural Environment Research Council, the Scottish Government and the University of Edinburgh.

Creating a fingerprint test will enable gas exploration and extraction to be carried out responsibly and should help address public concerns over this technology. It is important that action is taken to sample relevant sites before commercial extraction begins.”

Dr Stuart GilfillanSchool of GeoSciences