Short-term changes in seismic frequency response associated with shut-in of geothermal production wells

Abstract

Although seismic attenuation allows us to investigate the fluid phase change behavior in a geothermal reservoir, it is not easy to estimate attenuation from seismic reflection data because the attenuation estimation from the seismic reflected waves is easily affected by various factors such as tuning effects and premature attenuation analysis methods. We propose a stable method to implicate attenuation from time-lapse seismic reflection data by calculating the centroid frequency difference between seismic sections obtained at two different surveys. We apply the proposed method to time-lapse seismic reflection data acquired during a 12-day period before and after the shut-in of production wells in the Kakkonda geothermal field. Finally we infer that the zone implicated as an increase in seismic attenuation between different surveys might be associated with the fluid phase change of the shallow geothermal reservoir.