Monitoring geological carbon storage: detection threshold at the CaMI Newell County Facility and a look ahead at a sparse monitoring approach for gigatonne scale storage

Donald C. Lawton, Brendan Kolkman-Quinn, Marie Macquet, Kristopher A. Innanen

Monitoring Monitoring CO₂ injection at the CaMI Newell County Facility has continued with a broad range of monitoring technologies being implemented and evaluated. At the site, small volumes of CO₂ are being injected into a sandstone reservoir at 300 m depth, simulating a CO₂ leak from a deep geological carbon storage project. Time-lapse multi-offset and multi-azimuth vertical seismic profiles (VSP) and time-lapse electrical resistivity (ERT) surveys have both been successful at imaging less than 50 tonnes of CO₂ at this injection program. Detailed interpretation of the time-lapse data is that CO₂ has migrated up-section in the storage complex between 2021 and 2022. ERT time-lapse results also support this interpretation.

For seismic monitoring of large-scale geologic carbon storage projects there are 4 main challenges - repeatability, resolution, how often we repeat the seismic surveys, and the cost of full-scale surveys that extend over the anticipated area of the CO₂ plume and/or pressure front. One monitoring approach that we are proposing is to use sparse nodes of sub-permanent seismic sources and permanent receivers along with other monitoring technologies that can be deployed on an expanding basis during the injection program as the plume develops. The separation of the source and receivers will be determined by an optimum offset to maximize the signal-to-noise ratio of the reflections from the CO₂ storage zone.