Stress Conditions for Dip-Slip Events During Hydraulic Fracturing
N. Boitz and S. Shapiro
Event name: 81st EAGE Conference and Exhibition 2019
Session: Seismic Interpretation - Geomechanics
Publication date: 03 June 2019
Info: Extended abstract, PDF ( 1.06Mb )
Price: € 20
The observation of dip-slip events during hydraulic fracturing is widely discussed in recent literature. Here we investigate the stress conditions for these type of events. We show, that local rotations of the ambient stress field are required. These rotations can be very probable, if the horizontal and vertical stresses are close to each other. The necessary local changes in the stresses are caused by changes in the lithology between different rock layers. In some locations, the stress field becomes appropriately rotated and preexisting fault planes having the preferred orientation to fail as dip-slip events. If the ambient stress field is in a thrust faulting domain, horizontal fault planes are most likely to fail. In a normal faulting domain vertical fault planes are failing. Using this additional information we can explain not only the occurrence of dip-slip events, but can also define the correct fault- and auxiliary plane, which is impossible by just using the source mechanism itself.