Dynamics of Microseismicity by Hydraulic Fracturing - An Approach to Interpretation

Several basic dynamic processes related to propagation of hydraulic fracturing modify the effective stress in rocks and, therefore, are relevant for triggering of microseismicity. For instance, these are the creation of the new fracture volume, fracturing fluid loss and its infiltration into reservoir rocks as well as diffusion of the injection pressure into the surrounding rocks and inside the fracture. <br>Here, using real data we show that some of these processes can be seen from features of the spatio-temporal distributions of the induced microseismicity. Especially, the back front of the induced seismicity starting to propagate after termination of the fluid injection seems to be characteristic and informative for the aims of reservoir engineering.