... analysis of the fracture process zone was done on core plugs extracted adjacent to the main fracture. Fracture permeability and the number of pre-breakdown AE were used as main metric to compare performance of cyclic injection with monotonic injection. Our test results show that when the monotonic...

..., lamination, and brittleness control the activation of the layers. Lyons sandstone shows a wide brittle fracture with larger process zone with twice as much layer activation at lower stress levels. The fracturing process in shale is however a coupled function of rock fabric and calcite veins. The veins easily...