Simulation of Large Scale CO2 Injection at the Aquistore Injection Site, Estevan, SK

• Author / Creator

  Safaei Jazi, Ramin

• Physical impacts of CO2 injection into the Cambro-Ordovician Aquifer in the Williston Basin were simulated by using the TOUGH2-ECO2N simulator. A simulation domain starts from the top of the Precambrian crystalline bedrock up to the surface Glacial Till with a total vertical depth of 3345 metres including 11 aquifers and 12 aquitards. Three injection horizons were defined within the Cambro-Ordovician Aquifer and the lateral extent of the model domain was set to R=50 kilometres. A 30-year injection period followed by a 70-year post injection period at a rate of 1000 tonnes per day was simulated. Results showed that there was no CO2 leakage from the reservoir into the overlying formations for a 100-year period and CO2 appears to be safely trapped under the Icebox Aquitard. The maximum lateral CO2 migration reached up to 2 kilometres at 100 years after the injection and occurred within the middle injection horizon. Carbon dioxide saturation decreased significantly within the lower and upper horizons, while it remained almost unchanged within the middle horizon. Vertical pressure profile showed that there is no built up pressure above the Ordo-Silurian Aquifer. Lateral pressure profile also showed that the maximum pressure buildup occurs at the injection well and decreases laterally toward the model boundaries. Seventy years after the injection stops, almost the entire system reached the equilibrium or hydrostatic conditions except for the area around the injection well corresponds to a footprint area of 5.3〖 km〗^2. Results also showed no vertical brine migration across the Prairie Formation. Therefore, brine leakage into the shallow fresh water aquifers (e.g., Belly River Formation) is very unlikely. In order to obtain accurate results the injection cell width needs to be less than 1.5 metres and the vertical grid discretization also should be no more than 5 metres especially in the storage formation and its overlying sealing unit. Results also showed that no flow boundary conditions overestimate the excess pressure up to 1.5 Mpa compare to the hydrostatic boundary conditions. Thus, assigning the Dirichlet or hydrostatic boundary conditions is essential to obtain valid results. Results showed that MODFLOW could be used as an approach to simulate the head rise caused by the injection at the regions far away from the injector where only one phase is present. The Aquistore injection site appears to have a good storage potential to safely store supercritical carbon dioxide and will essentially contribute toward reducing CO2 emissions.

• Subjects / Keywords

  • Large-scale CO2 sequestration
  • TOUGH2-ECO2N
  • Aquistore injection site
  • Williston Basin

• Graduation date

  Fall 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3B56DF93

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.