Gas Monitoring Facility

Gas (CO2) measurement with a mobile open path laser system

The Gas Monitoring Facility provides equipment for the field measurement of gases in the near surface environment. The main focus of current research is on monitoring for leakage and the impacts of leakage from the geological storage of carbon dioxide (CO2). Research has also been carried out on radon, landfill gases, volcanic gases and for geothermal studies. The facility provides equipment for measuring concentrations of a range of gases in both the soil and the atmosphere and for determining the flux of gases across the soil/air boundary.

Background

Measurement of soil gas and gas flux in conjunction with botanical observations

Measurement of radon in soil gas was used in exploration for uranium from the 1960s, with equipment being developed in conjunction with Harwell. Radon, as well as CO2 and other gases, was used in exploration for other minerals in subsequent decades. More recently radon in soil gas has been used to assess indoor radon hazard, radiation dose to wildlife and as a more general tracer gas to identify fluid migration pathways and mechanisms.

Within the last decade near surface gas measurements have formed an important part of monitoring for carbon capture and storage projects and have been used on projects worldwide. This has involved research at sites of natural CO2 seepage in Italy, Germany and Greece, the Weyburn project in Canada, In Salah in Algeria and experimental injection facilities in the UK (ASGARD) and Norway (CO2 Field Lab). Observations have also been made at UK landfill sites. Projects include the EU Weyburn project, In Salah Gas Joint Industry Project, CO2GeoNet, CO2ReMoVe, CO2 Field Lab and RISCS. This has involved both national and international collaboration in particular with European and North American colleagues.

Capabilities

Continuous CO2 flux measurement by automated accumulation chambers
  • Soil gas sampling and analysis for CO2, oxygen (O2), methane (CH4), carbon monoxide (CO), hydrogen sulphide (H2S), radon (Rn), hydrocarbons
  • soil gas flux measurement for CO2 and CH4
  • atmospheric measurement of near-ground CO2 and CH4 using mobile open path lasers
  • continuous monitoring of CO2, CH4, temperature and pressure using buried or surface mounted probes with remote data access
  • continuous monitoring of CO2 flux by automatic accumulation chamber and eddy covariance techniques

Approaches in CO2 storage research

Continuous CO<sub>2</sub> and CO2 flux measurement by eddy covariance
  • observing natural background variations of near surface gases to define baseline conditions prior to CO2 injection
  • observing the changes in gas concentrations and fluxes arising from controlled or natural leakage of CO2. This helps in defining criteria to recognise leakage at CO2 storage sites and in assessing the detection capabilities of different types of equipment
  • drawing up monitoring strategies for generic and actual storage sites
  • quantifying leakage for emissions trading purposes

The detection and quantification of CO2 leakage are required under developing legislation as defined, for example, by EU Directives.

Contacts

Please contact Dr Dave Jones for further information