Detailed fracture and stress field in deep reservoir at Soultz have been estimated based on the multiplet-clustering analysis of induced microseismic events. The multiplet-clustering analysis is one of several high-resolution mapping techniques and can estimate multiplet clusters, which consist of group of similar microseismic events. As the result of the analysis, it is suggested that the multiplet clusters show planar structures that represent seismically activated fracture planes due to increasing of pore-fluid pressure in fractures. The strikes of the multiplet structural planes are dominating N-S, even though the orientation of structural planes in the shallow reservoir were estimated to be NW-SE. The stress field has also been calculated using the orientations of multiplet structural planes and their estimated slip directions. The maximum principal stress direction is estimated to be nearly vertical.
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