Investigating Injection Induced Fault Activation Through Geomechanical Stability Analysis
T. Kettlety, J.P. Verdon, M.J. Werner and J.M. Kendall
Event name: 81st EAGE Conference and Exhibition 2019
Session: Poster: Integrated Subsurface Studies - Carbonates and Geomechanics
Publication date: 03 June 2019
Info: Extended abstract, PDF ( 938.41Kb )
Price: € 20
Analysing the likelihood of hazardous induced seismicity prior to fluid injection is a key step in assessing the potential risks of the operation. Recent studies have investigated the criticality of mapped faults in their present day stress environment, calculating the potential for failure given an increase in pore pressure. We use similar methods to analyse the stability of two reactivated faults that were identified in a large microseismic dataset, acquired during the monitoring of a hydraulic fracture operation. Fault planes are found by fitting to event hypocentres, and an estimate for the in situ regional stress is calculated from local operator reports. A probabilistic Monte Carlo method of randomly sampling within the uncertainties of the input parameters is used, finding that the two faults are not critically stressed, requiring around 15 MPa of pore pressure increase to reach the failure criterion. These faults were only reactivated during non-consecutive injection stages, through which the faults appear to directly intersect. This suggests that poorly oriented faults such as these require more direct interaction with the injection to initiate failure and pose a risk to the operation.