Carbon capture and storage in St Lawrence Lowlands- Modeling of hydrogeological
potential impacts at basin scale
Abstract n°2658
Girou Olivier, Québec | QC, Canada
[email protected]
Lemieux Jean-michel, Université Laval, Québec | QC, Canada
Malo Michel, INRS - ETE, Québec | QC, Canada
KEYWORDS: CO2 injection, numerical simulation, basin-scale
During full-scale carbon capture and storage operations, important quantities of carbon are injected
into deep saline aquifers in order to significantly reduce greenhouse gases emissions. At the basin
scale, the injected fluid can cause pressure build, brine leakage into freshwater aquifers and water
table rise in unconfined shallow aquifers. In order to evaluate the suitability for long -term carbon
storage in deep saline aquifers, such environmental impacts need to be predicted. However, the
assessment of these impacts can be difficult due to the c omplex geometry of sedimentary basins.
In
this study, potential impacts related to an industrial-scale carbon capture and storage project in the StLawrence Lowlands basin (Quebec, Canada) are studied with a specific attention t o the role played by
regional faults that divide the basin into multiple compartments. Groundwater flow simulations were
conducted with the FELOW numerical model using a detailed geological model of the basin that
includes the regional normal faults. The investigated scenarios consider an injected flow rate of
ranging from 1 to 10 Mt yr over a period of 100 years followed by a post -injection period of a 1000
years. Particle tracking was used to estimate brine migration.
Normal faults, which allegedly exhibit a
low hydraulic conductivity, play a major role in pressure build up distribution and brine migration. The
simulations suggest that neither pressure build -up nor brine leakage will occur in the outcrop zone of
the basin where shallow aquifers are exploited. S ensitivity analysis also suggests that such impacts
can only be achieved with an unfavorable set of paramet ers. It is also found that specific storage,
which is the less accurately defined parameter, is the most important parameter influencing p ressure
build-up.
This study shows that basin-scale impacts of carbon injection may not limit injection rate up
to 10 Mt y in the St-Lawrence lowlands. However, normal faults are poorly investigated in the basin
and a better knowledge of faults hydrodynamic properties is needed to validate these findings.