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Fluid Injection and Time‐Dependent Seismic Hazard in the Barnett Shale, Texas
Author(s) -
Zhai Guang,
Shirzaei Manoochehr
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl077696
Subject(s) - poromechanics , induced seismicity , geology , hydrogeology , seismology , pore water pressure , seismic hazard , oil shale , geotechnical engineering , porosity , paleontology , porous medium
The Barnett Shale in Texas experienced an increase in seismicity since 2008, coinciding with high‐volume deep fluid injection. Despite the spatial proximity, the lack of a first‐order correlation between seismic records and the total volume of injected fluid requires more comprehensive geomechanical analysis, which accounts for local hydrogeology. Using time‐varying injections at 96 wells and employing a coupled linear poroelastic model, we simulate the spatiotemporal evolution of pore pressure and poroelastic stresses during 2007–2015. The overall contribution of poroelastic stresses to Coulomb failure stress change is ~10% of that of pore pressure; however, both can explain the spatiotemporal distribution of earthquakes. We use a seismicity rate model to calculate earthquake magnitude exceedance probability due to stress changes. The obtained time‐dependent seismic hazard is heterogeneous in space and time. Decreasing injection rates does not necessarily reduce probabilities immediately.