Rate and State Friction Analysis of the Upper Devonian Duvernay-Wabamun Interval and the Lower Triassic Montney Formation
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2022-01-12
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Abstract
Production of unconventional hydrocarbon resources is an important activity for the economic prosperity of North America. To enhance productivity from unconventional reservoirs in the Western Canada Sedimentary Basin hydraulic fracturing (HF) is routinely employed, which involves the injection of highly pressurized fluids into the subsurface to generate multiple fractures within hydrocarbon reservoirs and increase overall permeability. Along with the increase in HF activities, there has been a parallel increase in induced seismic events in the vicinity of the injection wells. Fault reactivation is accepted as the triggering mechanism for induced seismicity. However, the underlying mechanism that leads to fault reactivation is still not very well understood. Recent studies have suggested that seismic slip of a fault, whose epicentre may be at some distance from HF activities, may arise due to loading from HF driven aseismic slip of the fault near the injection zone. The occurrence of aseismic or seismic slip is dependent on the rate and state frictional properties of the rock. To gain insights into the rate and state friction behavior of reservoir rocks that are typically subjected to HF stimulation, and surrounding formations, in Western Canada, a series of direct shear tests including velocity stepping and slide-hold-slide stages were conducted using a double direct shear assembly under a range of stress conditions to capture those that may occur in the subsurface. Simulated fault gouge material was obtained from samples belonging to the Perdrix, Shulphur Mountain, Ireton, Winterburn and Wabamun formations and groups, to assess the range of rate-state frictional behavior that might occur in the subsurface. Results show that frictional strength and slip stability of the rock samples were dependent on applied normal stress conditions and inherent rock mineralogy. For the majority of the rocks tested aseismic slip was the dominant response, although a small number of rock samples exhibited seismic slip at low normal stresses. Understanding of the rate-state behavior of rock formations will help in assessing the potential contribution of aseismic loading on earthquake nucleation in Western Canada, and lead to greater insights into the triggering of seismic events caused by hydraulic fracturing processes.
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Hernandez Borbon, J. R. (2023). Rate and state friction analysis of the Upper Devonian Duvernay-Wabamun interval and the Lower Triassic Montney Formation (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.