Mapping CO2 And CH4 Emissions: Field-Trial Evaluation Of LightSource For Remotely Estimating The Locations And Mass Emission Rates Of Sources

We describe and report the field performance of LightSource, a Shell proprietary technique for remotely detecting and locating multiple gas emission sources and simultaneously estimating their individual mass emission rates. The system was originally developed to provide atmospheric monitoring over the Quest CO2 storage site in Canada. It operates automatically using a ground-based optical sensor and is suited to continuous area monitoring. This new work supports enhanced CO2 source detectability by exploiting any naturally present CH4 released through CO2 migration in the subsurface. In these tests, we use a radically new open-path optical beam gas sensor based on Laser Dispersion Spectroscopy, LDS, which offers substantial operational advantages over the commercially available sensors we have used previously. We report on the method and performance achieved during 17 calibrated methane gas releases at the Chilbolton Observatory test site in the UK. The resulting concentration and wind data were processed using our LightSource code.