Fracturation héritée et induite à partir d'images acoustiques et électriques de paroi

International audienceIn the framework of a European Geothermal Project, three boreholes were drilled at Soultz-sous-Forêts, Rhinegraben, which reached the hot and fractured granitic basement. Fresh water will be injected intot one borehole, an d revovered hot from the other. To designs this reservoir, a knowledge of both the paleo-fracture pattern in the granite ant the orientation of the present-day stress field is required.Fracture analysis was carried out on borehole images coming from different boreholes. Two types of logging tools were used to product these images: acoustic tools (BHTV, UBI) and electric tools (FMI, FMS). Fractures observed have two origins: pre-existing fracture and induced fractures