Cabarcas, Carlos; Davogustto, Oswaldo
On a multistage fracturing job monitored from a borehole for microseismic activity, high magnitude microseismic events are characteristic of reactivated faults. When plotted against their distance from the monitor well and compared to events from other hydraulic stimulation stages, it becomes apparent that these microseismic events are associated with fault reactivation. Here, I present an example Magnitude vs. Distance Plot used to discriminate between fault reactivation (i.e. stimulation failure) and other successfully completed stages. Plot analysis and treatment records suggested reactivation of a fault during the hydraulic fracturing, but no other subsurface data supported this interpretation. As soon as a 3-D reflection seismic volume was available, it was clear that microseismic events aligned with a fault plane interpreted on seismic profiles, corroborating the hypothesis of a preexisting fault reactivation. This work shows that in the absence of other subsurface data (or integrated with all the available information), Magnitude vs. Distance Plots provide a useful tool to analyze stimulation results and support decisions regarding completion strategies in real time.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013