Patent ID: 8605544

Claim:
A system for monitoring seismicity during fluid injection at or near a hydrocarbon reservoir comprising: a first set of seismic sensors for deployment at a site for collecting seismic data; a second set of seismic sensors for sub-surface deployment at the site at a depth lower than the first set of sensors for collecting seismic data, the first set of sensors having a lower frequency response and being less sensitive to magnitude saturation than that of the second set of sensors; and a data collection system in communication with the first and second set of seismic sensors, the data collection system being configured to determine if seismic data from the first set of seismic sensors for a seismic event is indicative of a biasing of seismic data from the second set of sensors and if so, then using the seismic data from the first set of seismic sensors exclusive of the seismic data from the second set of seismic sensors to determine a seismic event magnitude for the seismic event, and if not then using the seismic data from at least the second set of seismic sensors to determine a seismic event magnitude for the seismic event.