Master of Science
The injection of fluid into rock masses as a part of industrial processes, such as hydraulic fracturing, can lead to an increase in seismic activity. The movement of the injected fluid and resulting stresses can be simulated and analyzed. One aspect of this analysis is the predicted rate of seismic activity, obtained via the Dietrich rate-and-state law and the Coulomb Failure Stress. This work produces simulations for two fracturing scenarios in the Duvernay Shale region. Model parameters, such as layer permeability and timing of fault slip, are varied to determine their impact on the model results. The simulated results show that increases in activity are primarily derived from pore pressure increases, and that changes in permeability between models have the most effect on the results.
Summary for Lay Audience
Hydraulic fracturing, commonly known as fracking, involves the injection of large amounts of water into a section of rock, and is known to be capable of leading to earthquakes. This leads to an increase in pressure that can put stress on the rock surrounding the injection point. These stresses, along with the movement of the water through the rock, can be examined to determine the potential for earthquakes to occur. The pressure increases and stresses on the rock can be combined into a single measurement that can be used to estimate the rate of seismic activity. This work produces simulations for two fracturing scenarios in the Duvernay Shale region in Alberta. These models include variations to determine which aspects are most important, such as how easily the water, can flow through the surrounding rock and when the fault moves in response to the changing stress or increased pressure. Results from the simulations show that the former of those parameters has one of the largest impacts in the overall rate of earthquake occurrence. The results also show that most of the earthquakes were triggered as a result of pressure increases instead of stress changes within the rock itself.
Hulls, Charles KW, "Geomechanical Modeling of a Fault During Fluid Injection" (2022). Electronic Thesis and Dissertation Repository. 8780.
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