| Popis: |
Since July 2008 CO 2 is injected into a saline aquifer near Ketzin, in Germany. The reservoir used for CO 2 injection is the Stuttgart Formation of Triassic age, located at a depth of about 650 m. Close to the injection well, TNO designed and implemented a permanent shallow seismic monitoring system. The system consists of 3C-geophones and hydrophones at locations along a line of 130 meters and at depths up to 50 meters. Since September 2009 up to date the array has recorded passive seismic data continuously. A procedure has been developed to automatically detect and locate very low magnitude seismic events. This paper describes the first results, including a calibration test with a known surface source, where two months data have been investigated in detail. Over 20.000 seismic events were detected automatically during this period, of which the 200 strongest ones were analyzed in more detail. Localization of these 200 events learned, that more than 99% originate from a single location at the surface, most likely related to industrial activity. Much weaker events originating from the subsurface have been observed as well. Interpretation and localization of these events is ongoing. |
