Konstantinovskaya, Elena; Rutqvist, Jonny et Malo, Michel (2014). CO₂ storage and potential fault instability in the St. Lawrence Lowlands sedimentary basin (Quebec, Canada): Insights from coupled reservoir-geomechanical modeling. International Journal of Greenhouse Gas Control , vol. 22 . pp. 88-110. DOI: 10.1016/j.ijggc.2013.12.008.
Ce document n'est pas hébergé sur EspaceINRS.Résumé
Coupled reservoir-geomechanical (TOUGH-FLAC) modeling is applied for the first time to the St. Lawrence Lowlands region to evaluate the potential for shear failure along pre-existing high-angle normal faults, as well as the potential for tensile failure in the caprock units (Utica Shale and Lorraine Group). This activity is part of a general assessment of the potential for safe CO₂ injection into a sandstone reservoir (the Covey Hill Formation) within an Early Paleozoic sedimentary basin. Field and subsurface data are used to estimate the sealing properties of two reservoir-bounding faults (Yamaska and Champlain faults). The spatial variations in fluid pressure, effective minimum horizontal stress, and shear strain are calculated for different injection rates, using a simplified 2D geological model of the Becancour area, located ∼110 km southwest of Quebec City. The simulation results show that initial fault permeability affects the timing, localization, rate, and length of fault shear slip. Contrary to the conventional view, our results suggest that shear failure may start earlier for a permeable fault than for a sealing fault, depending on the site-specific geologic setting. In simulations of a permeable fault, shear slip is nucleated along a 60 m long fault segment in a thin and brittle caprock unit (Utica Shale) trapped below a thicker and more ductile caprock unit (Lorraine Group) – and then subsequently progresses up to the surface. In the case of a sealing fault, shear failure occurs later in time and is localized along a fault segment (300 m) below the caprock units. The presence of the inclined low-permeable Yamaska Fault close to the injection well causes asymmetric fluid-pressure buildup and lateral migration of the CO₂ plume away from the fault, reducing the overall risk of CO₂ leakage along faults. Fluid-pressure-induced tensile fracturing occurs only under extremely high injection rates and is localized below the caprock units, which remain intact, preventing upward CO₂ migration.
| Type de document: | Article |
|---|---|
| Mots-clés libres: | coupled reservoir-geomechanical modeling; fault seal capacity; shear slip; tensile fracturing; CO₂ storage; St. Lawrence Lowlands |
| Centre: | Centre Eau Terre Environnement |
| Date de dépôt: | 17 avr. 2018 20:25 |
| Dernière modification: | 17 avr. 2018 20:25 |
| URI: | https://espace.inrs.ca/id/eprint/5624 |
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