HR: 0830h
AN: S41D-01    [Abstracts]
TI: Application of Coherence Collapsing Relocation Method to Induced Microseismicity Collected at European and Australian Hot Dry Rock Sites
AU: * Asanuma, H
EM: asanuma@ni2.kankyo.tohoku.ac.jp
AF: Graduate School of Environmental Studies, Tohoku University, Aramaki aza Aoba, 6-6-20, Sendai, 980-8579 Japan
AU: Izumi, T
EM: izumi@ni2.kankyo.tohoku.ac.jp
AF: Graduate School of Environmental Studies, Tohoku University, Aramaki aza Aoba, 6-6-20, Sendai, 980-8579 Japan
AU: Niitsuma, H
EM: ni@ni2.kankyo.tohoku.ac.jp
AF: Graduate School of Environmental Studies, Tohoku University, Aramaki aza Aoba, 6-6-20, Sendai, 980-8579 Japan
AU: Baria, R
EM: baria@soultz.net
AF: Bestech, Landauer Straɞe 28, Kandel, Germany
AU: Wyborn, D
EM: dwyborn@geodynamics.com.au
AF: Geodynamics, 349 Coronation Drive, Milton, QLD Australia
AB: The authors have investigated a variation of the Collapsing method. The original Collapsing method (Jones and Stewart, JGR, 1997) is a mapping method for re-locating microseismicity that utilizes information from all the events in the data set. It has a reasonably good ability to emphasize the structure of the whole seismic cloud. However the original Collapsing method cannot resolve seismic structures with comparable sizes to the spatial distribution of the residual. This limitation of the original Collapsing method can cause difficulties in interpreting the hydraulic behaviour of a hot dry rock (HDR) reservoir. As a result, mapping techniques with higher resolutions, such as multiplet analysis and clustering analysis, have typically been used to delineate finer scale seismic structure. In the version of the Collapsing method introduced here the degree of coherence among the seismic traces is incorporated into the method. The new method is referred to as the 'Coherence Collapsing' method, and it aims to selectively relocate a group of multiplets to a common point. The Coherence Collapsing method can be used in semi-realtime to refine the locations of multiplets. The Coherence Collapsing method is based on the original Collapsing method, but the parameters in the analysis are optimized from synthetic studies to improve the reliability of the location of the multiplets. The method has been applied to the microseismic data sets collected during hydraulic stimulation at the HDR project sites in Soultz, France and Cooper Basin, Australia. Comparisons between locations derived from the Coherence Collapsing method and the single event determination/JHD method reveals a more structured distribution of events and less diffuse multiplet groups. The distribution of the multiplets are correlated with the dominant flow path estimated by integrated analysis of multiplets, logging, geological data and hydraulic records, suggesting that the Coherence Collapsing method can be effectively used for on-site monitoring of the reservoir creation process.
DE: 7200 SEISMOLOGY
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2005 Joint Assembly