Self-consistency in Scaling Relations for Seismicity Induced During Hydraulic Fracture Stimulations

Abstract

We investigate seismic scaling relationship using two microseismic datasets, smaller events with moment magnitude below zero and larger events with magnitude above zero. Both datasets are recorded by fully integrated passive seismic monitoring programs in the same field but during different time periods. We examine the relationship between the occurrence of small magnitude events (M < 0) and the fracture and stress conditions that may lead to occurrence of larger events. The results show that over all scales of observation the events follow a selfsimilar behavior; however, the small magnitude events are generally lower in stress release compares to observations for the larger events. The differences for smaller and larger magnitude events can be explained by the observed failure mechanisms where smaller events tend to be driven by shear-tensile failures of pre-existing discrete fractures (joints) whereas the larger events appear to be dominated by shear driven failure processes associated with pre-existing faults. These observations suggest that the occurrence of large events is probably due to a stress transfer resulting from the stress changes or transfer resulting from the occurrence of smaller-magnitude events in the volume.