Microseismic monitoring of a CO2 Injection: the case study at In Salah, Algeria

We analyze microseismic data induced during CO2 injection at In Salah, Algeria. We detected over 5000 microseismic events using a master event waveform cross-correlation approach. Interpretation of the microseismic events is mainly based on S-P wave onset times and polarization angles of the P-waves but also includes source parameter determination. Events can be classified in various event clusters according to their S-P traveltimes and azimuth. The microseismic activity shows correlation between seismological parameters and injection data. Moment magnitudes have been determined in the frequency domain. Most magnitude estimates are between -1 and 0, with a few larger magnitude events up to Mw 1. B-values of events clusters have been determined and show significant variations between the clusters.