HDR Investigations Down to 4QOm Depth in Crystalline Rocks at Falkenberg

Abstract

In a granite massif in NE BavarialFR Germany in the depth range down to 400 m an artificial heat exchange system with an extension of more than 25000 m2 was stimulated by hydraulic fracturing. The stimulated fracture was intersected by six additional boreholes up to 80 m distance from the frac initiation. These intersection boreholes provided access to the fracture system at different distances·between injection point and extraction point during circulation and allowed systematic experimental investigations on the hydraulic, mechanic an thermal behavior at various pressure stages. Appropriate models extend the results to greater depth with regard to HDR systems in deep rock sections.