BGS facilities for the collection and measurement of gases in the near surface environment. This includes field and laboratory capability for measuring gases in the shallow subsurface (e.g. soils), fluxes from the soil into the atmosphere and determinations in the atmosphere just above the ground surface. Included are techniques for single measurements and systems capable of repeated (continuous) measurement. As well as gas monitoring equipment the facility includes techniques for collecting ancillary data to help interpret those measurements, such as weather stations. The facility includes a wide range of equipment and expertise for gas monitoring, particularly aimed at near surface monitoring in relation to CCS. This includes innovative survey methods for CO2 leakage detection, such as the use of mobile open path laser systems for CH4 and CO2, innovative use of techniques more usually applied in different fields of study (e.g. eddy covariance and continuous flux monitors) and a capability to examine the origin of gases through examining the relationship of CO2 to other gases and the use of carbon isotopes. These directly address the need to monitor large areas rapidly with sensitive equipment in order to detect leakage, determine the extent of that leakage and quantify the amount of leakage, as required by legislation, including the temporal variability of the gas emissions. Recently the scope of research has been extended to include work on baselines in areas prospective for shale gas and geothermal exploration.
Monitoring of near surface gases for CCS onshore needs to include a range of capabilities including: wide area coverage to detect potential surface seepage of CO2 over the large surface footprint of a large scale (Mt/year) storage site, continuous monitoring of possible leakage pathways (e.g. wells and faults), discrimination of gas source (is the CO2 coming from storage at depth or natural CO2 produced by near surface processes?) and quantification of any emissions of stored CO2. The Gas Monitoring facility has capabilities to address all of these issues through mobile lasers (wide area coverage), continuous flux and gas concentration (in soil or near ground atmospheric air) monitors and the use of gas ratios (CO2 to O2, N2, and CH4) and access to lab facilities for C isotopes to discriminate the source of any CO2 anomalies identified. The facility has been upgraded recently to include scanning laser (CH4) for continuous monitoring of areas up to hundreds of metres in radius and there are developments under way to further extend the capability (e.g. airborne measurements with Unmanned Aerial Vehicles, improved sensitivity flux measurements and field isotopic determinations).
We have worked in conjunction with colleagues from Italy and France for more than 10 years to develop monitoring approaches for CCS. We have discussed and compared results with international colleagues at injection test sites (actual or proposed) in Canada, the US, Brazil, Australia and S Korea and are involved in proposals to develop direct international collaboration at a natural CO2 site in South Africa and between developing injection sites in the UK (GeoEnergy Test Bed), Canada (Field Research Station in Alberta), Australia (Otway and Ginninderra) and South Korea (K-COSEM project). The facility has gained extensive experience in the use of these methods through their use at natural laboratory sites (where natural seepage of CO2 is taking place) in Italy, Germany and Greece, experimental injection and release sites in the UK and Norway (ASGARD and CO2 Field Lab) landfill sites and industrial scale CO2 storage sites such as Weyburn, Canada and In Salah, Algeria. This experience has been applied to help draw up monitoring plans for proposed future CCS projects, for example in Denmark and Germany.