Microseismicity During the 2005 Habanero EGS Stimulation in the Cooper Basin of South Australia

Abstract

We apply the empirical Matched Field Processing (MFP) method to continuous seismic data to detect and determine preliminary locations for more microearthquakes than can be detected using only conventional earthquake detection techniques. We demonstrate that empirical MFP can complement existing catalogs and techniques by using archived seismic information to increase earthquake catalog completeness. Refined earthquake catalogs can then be applied to, for example, subsequent improved b‐value studies to investigate the frequency-magnitude relationship of microseismic events during and after stimulation. The empirical MFP method finds new events in the continuous data stream by identifying signals that match pre‐defined master templates. We construct representative master templates using known events identified during the 2005 Habanero Stimulation within Cooper Basin, Australia. The master templates are matched to continuous data obtained from the local 8-station borehole seismic array. Of the 8873 events that occurred during the combined 2005 Habanero 1 and Habanero 2 stimulation, 275 events with particularly high signal-to-noise (SNR) are identified and incorporated into this study. During the first week of the Habanero 1 stimulation, 1288 events were identified using traditional earthquake detection methods. The empirical MFP method identified 994 additional events, or approximately 75% more events, during this time frame showing that this advanced microearthquake detection methodology is well adapted for hot fractured rock environments. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE‐AC52‐07NA27344.