Repeated Seismic Reflection Measurements In The Kakkonda Geothermal Field
Journal Article: Repeated Seismic Reflection Measurements In The Kakkonda Geothermal Field
AbstractTemporal variations in seismic reflection responses apparently caused by changes within a geothermal reservoir have been detected in the Kakkonda field, where production wells were shut in prior to annual power plant maintenance. Three seismic surveys were carried out during a 12-day period spanning the shut-in period. Receivers were deployed without replanting throughout the surveys, providing good data acquisition repeatability. We applied prestack time migration (PSTM) to each of the three seismic data sets and calculated the cross-correlation coefficients between PSTM sections. Our results indicate that the reservoir changes associated with shut-in are large enough to be seismically detectable. The region over which the seismic response changed corresponds to the zone of geothermal fluid flow paths inferred from reservoir temperatures and geochemical data. We have also compared our cross-correlation maps with the epicenters of micro-earthquakes, which are inferred to indicate the existence of fractured zones. Dense regions of micro-earthquake activity lie within the seismically identified zone of changes in reservoir properties. We demonstrate the feasibility of repeated seismic surveys in providing substantial improvements in temporal resolution during geothermal reservoir monitoring.
- Jun Matsushima, Toshiyuki Yokota, Yasukuni Okubo, Shuichi Rokugawa, Keiji Tanaka, Terumitsu Tsuchiya, Norifumi Narita and Kazuyuki Tani
- Published Journal
- Journal of Volcanology and Geothermal Research, 2004
- Not Provided
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Jun Matsushima,Toshiyuki Yokota,Yasukuni Okubo,Shuichi Rokugawa,Keiji Tanaka,Terumitsu Tsuchiya,Norifumi Narita,Kazuyuki Tani. 2004. Repeated Seismic Reflection Measurements In The Kakkonda Geothermal Field. Journal of Volcanology and Geothermal Research. (!) .