Consideration of Stress Induced Permeability Changes Within a Poroelastic Model Framework for Induced and Triggered Seismicity
Abstract
Observational studies have long suggested that stresses generated from earthquakes can alter permeability, as frequently evidenced by higher levels of fluid outflow, as measured at the surface. Similarly, by means of tidal deconvolution and opportunely placed boreholes, more precise measurements of seismically induced permeability changes may be obtained. As evidenced from borehole observations, this process of permeability change appears to be a transient process, with measured permeability values regressing to a mean value after some time. What is less clear, however, is how such a temporary change in permeability might affect environments already containing critically stressed faults.
We seek to investigate the phenomenon of seismically induced permeability change initially from an observational perspective, taking account of cases where permeability appeared to have been altered by coseismic effects, and considering the potential influence from dynamic and static stresses respectively. Similarly, we seek to draw a connection from a conservation of energy perspective between seismic input and observed permeability change, along with a decay function fit to the observed value regression. Lastly, we seek to fit the relations gained from our observational studies to guide a permeability update function within an existing, fully coupled, and fully implicit poroelastic model defined for heterogeneous reservoirs in the presence of production wells, injection wells, and critically stressed faults, modeled using the Mohr-Coulomb failure criterion. Through the use of this numerical model, we seek to investigate not only the potential for induced seismicity resulting solely from anthropocentric causes, but also the likelihood for prior seismicity serving as a catalyst for further events that might not be otherwise triggered from injection or production alone.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.S33C0592W
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGYDE: 7223 Earthquake interaction;
- forecasting;
- and prediction;
- SEISMOLOGYDE: 7230 Seismicity and tectonics;
- SEISMOLOGYDE: 8168 Stresses: general;
- TECTONOPHYSICS