Modeling Microseismic Activity in the Newberry Enhanced Geothermal System

Abstract

During the stimulation of an enhanced geothermal system (EGS), the timing and location of induced microseismicity is one of the key indicators for the stimulation’s effectiveness. In our analysis, we constructed a 3D, fully-coupled, thermo-hydraulic-mechanical (THM) model of the Newberry EGS, which includes a realization of a discrete fracture network (DFN), using the GEOS platform (Settgast et al., 2016; Sherman et al., 2016). We perform a statistical analysis of the shear and normal dislocations on the DFN to estimate the degree of microseismic activity within voxelized regions of the model. This method properly quantifies the effects of microseismic activities that would otherwise require element sizes too small to be computationally tractable. We then apply the same algorithm to an equivalent estimate of activity using the field microseismic catalog. Using the predicted pressure, flow rate, and microseismic activity data, we calibrate our model against a set of hydroshearing stimulations in the region performed by AltaRock during 2012 and 2014.