Application of microseismic multiplet analysis to the Basel geothermal reservoir stimulation events |
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| Authors: | BC Dyer U Schanz T Spillmann F Ladner MO Häring |
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| Institution: | 1. Semore Seismic Ltd, The Athenaeum, Kimberley Place, Falmouth TR11 3QL, UK;2. GEOenergie Bayern GmbH, Blumenstrasse 16, 93055 Regensburg, Germany;3. Nagra, Hardstrasse 735430 Wettingen, Switzerland;4. Geothermal Explorers International Ltd, Schlossstrasse 3, 4133 Pratteln, Switzerland |
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| Abstract: | The stimulation of a geothermal well in Basel, Switzerland produced a distribution of microseismic event locations with an overall alignment in the direction of the maximum horizontal stress. Fault plane solutions of individual larger events indicated movements on fracture planes at an angle to the maximum horizontal stress that could not be reliably interpreted from the event locations. To obtain higher resolution images of the microseismic event locations, events with similar waveforms have been identified by multiplet analysis. A number of receivers were used in the multiplet processing to ensure each multiplet is represented by a unique group of waveforms. The location accuracy within each multiplet has been significantly improved using cross‐correlation to refine the shear‐wave traveltime picks. The distribution of events within each multiplet can be interpreted as being due to movements on a single fracture or a number of near parallel fractures. It is shown that whilst the overall distribution of events is around the direction of the maximum horizontal stress, the individual multiplets representing fracture planes have a variety of azimuths and dips. |
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| Keywords: | Geothermal Multiplet Multiple sensor processing |
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