Experimental investigation of thermal cycling effect on fracture characteristics of granite in a geothermal-energy reservoir

The fracture characteristics of fine-grained granite were examined for a potential geothermal-energy reservoir. The granite was thermally cycled in a furnace between 100 °C and 300 °C and its mechanical behavior and meso-crack characteristics were analyzed. The results indicate that thermal cycling leads to decreased fracture toughness (Keff), absorbed energy (U), longitudinal wave velocity (Pv), and increased permeability (K) in granite. These...