Using Heated Column Experiments to Investigate the Effects of In-Situ Thermal Recovery Operations on Groundwater Geochemistry in Cold Lake, Alberta

Abstract

Groundwater monitoring studies of the Cold Lake-Beaver River (CLBR) basin in Alberta have linked increases in arsenic concentration to subsurface heat release caused by in-situ thermal recovery operations. Aquifer sediments that are exposed to localized elevated temperature conditions undergo increased rates of water-rock interactions have the potential to liberate contaminants in potable groundwater sources at near-neutral pH levels. Preliminary laboratory experiments and field investigations have shown an increased rate of reaction at temperatures >80°C with respect to mineral dissolution and the release of contaminants. In this study, three heated column experiments were carried out using different mineralogical compositions of saturated aquifer materials, while exposing the materials to temperatures up to 90°C and monitoring water geochemistry. Aquifer materials that were used in the three experiments included: quartz sand; quartz sand with pyrite; and sediments collected from the CLBR region.