Effects of long-term fluid injection on induced seismicity parameters and maximum magnitude in northwestern part of The Geysers geothermal field

Kwiatek, G., P. Martínez-Garzón, G. Dresen, M. Bohnhoff, H. Sone, and C. Hartline (2015). Effects of long-term fluid injection on induced seismicity parameters and maximum magnitude in northwestern part of The Geysers geothermal field, J. Geophys. Res. 120, DOI 10.1002/2015JB012362. [ Article Page ]

FilePasswordAction
2015_JGR_Kwiatek_TheGeysersLongTerm.pdf 

We analyze long-term temporal and spatial changes in statistical, source, and stress characteristics of one cluster of induced seismicity recorded at The Geysers geothermal field in relation to the field operations, fluid migration, and constraints on the maximum likely magnitude. The seismicity catalog of 1776 events was relocated, and the source characteristics including foca lmechanisms and static source parameters were refined using first-motion polarity, spectral fitting, and mesh spectral ratio analysis techniques. The source characteristics together with statistical parameters (b value) and cluster dynamics were used to investigate and understand the details of fluid migration scheme in the vicinity of injection wells. The observed temporal, spatial, and source characteristics were clearly attributed to fluid injection and fluid migration toward greater depths, involving increasing pore pressure in the reservoir. The seasonal changes of injection rates were found to directly impact the shape and spatial extent of the seismic cloud. A tendency of larger seismic events to occur closer to injection wells and a correlation between the spatial extent of the seismic cloud and source sizes of the largest events was observed suggesting geometrical constraints on the maximum likely magnitude and its correlation to the average injection rate and volume of fluids present in the reservoir.
  • Version
  • 2 Download
  • 2.47 MB File Size
  • 1 File Count
  • 13 November 2018 Create Date
  • 13 January 2019 Last Updated
  • Download