Muon detector could help identify CO2 storage sites

One of the major challenges in the development of Carbon Capture and Storage technology is measuring the capacity of the underground chambers that will be used to store captured CO2.

But an advanced probe being developed by particle physicists at Sheffield University that exploits the properties of cosmic ray muons (naturally occurring sub-atomic particles that pass through Earth) could offer a more accurate and lower cost solution than existing seismic monitoring techniques.

Currently a method known as ‘4D Seismic Surveying’ (4SS) is used, which typically takes place aboard large ships at a cost of around £5.5m per survey.

Working with funding from the Department of Energy and Climate Change (DECC) and Premier Oil, the Sheffield team has been testing the technology at an underground research facility in Boulby mine near Redcar, which is the UK’s deepest working Potash mine.

The detectors have been deployed deep underground where they are able to monitor muons travelling through the North Sea and then through a kilometre of rock to reach the cavern in the Boulby Mine. As the tide changes above the mine, the amount of water that muons travel through changes and these variations can be picked up by the detector system.

The next step is to design a system that could be used as a probe in the boreholes of the oil field and other potential geological repositories proposed for CO2 storage. The researchers are aiming to develop a working prototype by 2015.

Sheffield University Prof Lee Thompson – who is heading up the project said: ’The detectors need to be small enough to fit into existing bore holes drilled around the underground CO2 storage chambers which are typically only20 cm in diameter. They also need to be able to resist elevated temperature, as it usually exceeds 40ºC in the boreholes.’