Study of Microseismic Doublet/Multiplet for Evaluation of Subsurface Fracture System in Soultz HDR Field

Abstract

Reservoir structure of Soultz HDR field has been studied using doublet/multiplet. In this study, the reservoir structure characteristics are evaluated in detail using precise source location of induced microseismic doublet/multiplet, also the origin of multiplets is discussed. Microseismic events with similar waveforms have been corrected with the microseismic data set obtained during a hydraulic fracturing experiment in 1993, and the relative source locations have been determined by doublet analysis based on the cross spectrum analysis. The orientation of structural planes derived from hypocenter distributions of multiplets suggested that the dip angles of structural planes are changing with depth. The migration of seismic sources with time suggests that the doublet/multiplet tends to be located at the edge of the microseismic cloud.