Microseismic event analysis using multi-technology sensors at the Quest CCS site

Microseismic monitoring plays a crucial role in assessing the effectiveness and integrity of Carbon Capture and Storage (CCS) projects. By the detection of microearthquakes we can gain real-time insights into the pressure and stress perturbation due to injection operations, aiding in the detection of potential leakage and ensuring the long-term viability of carbon sequestration efforts.

At the Quest CCS site in Alberta, Canada, CO2 injection into a 2 km depth saline reservoir is ongoing since 2015 at a rate of one million tonnes per year.  Several hundreds of small-magnitude seismic events have been located in the Precambrian basement below the reservoir.  A spatio-temporal analysis of seismicity reveals clustered as well as more diffuse distributions of events.  At the Quest site various microseismic monitoring technologies are in place including a downhole 8-level 3-component geophone string, temporary surface nodes arranged in mini-arrays, and downhole optical distributed acoustic sensing (DAS) fiber. The site offers an ideal opportunity to compare and combine the different setups with respect to event detection thresholds and location uncertainties. We demonstrate the importance of advanced signal and array processing techniques and highlight the advantages and disadvantages of different sensor technologies.