Temporal Changes in Seismic Velocity and Attenuation at The Geysers Geothermal Field, California, From Double?Difference Tomography

Water injection and Enhanced Geothermal System (EGS) technologies have been used to exploit heat resources from geothermal reservoirs. Detecting spatial temporal changes in reservoir physical properties is important for monitoring condition due water EGS. Here, we determine high-resolution models of the three-dimensional P wave velocity attenuation (Vp Qp) structures between years 2005 2011 northwestern part The Geysers field, California, using double-difference seismic tomography. northwest has a shallow normal temperature (NTR) underlain by high (HTR) that substantial underutilized but may be more fully utilized future through In southeastern Geysers, however, EGS successfully unintentionally applied at least 50 because waters injected into NTR flowing HTR. Our are well resolved this area show HTR different responses (seismicity, Vp, injection, which can explained injection-induced differences fracturing saturation likely related their geological properties. results indicate joint analysis seismicity, velocity, valuable characterizing conditions. suggest high-permeability zones and/or pre-existing permeable fault success potentially other systems.