Open File Report 1996-01

Open File Report 1996-01

OFR 1996-01

Hydrogeology of the Cold Lake Study Area Alberta, Canada

The study determined the baseline hydrogeological situation prior to development of commercial in-situ recovery operations in the oil sands deposit because of the possible effect these may have on the natural flow system, specifically on the near surface potable groundwater resources.

The Cold Lake study area is defined as Tp 55-69, R 1-17. W 4 Mer. and covers approximately 23 800 km� in east-central Alberta. The Cold Lake oil sands deposit occupies a significant portion of the eastern half of the study area.

Although detailed lithological studies were not performed, the information presents which stratigraphic units may act as aquifers, aquitards or aquicludes. Of particular concern were the effects of missing stratigraphic units (due to erosion or non-deposition) and of salt solution, as missing aquitards or aquicludes allow juxtaposition of aquifers. Because of this evaluation of the regional Phanerozoic history, the authors decided to limit the hydrogeological study to strata younger than the Middle Devonian Prairie Formation halite. Even this restriction meant that significant contact of aquifers of widely different ages occurred in some parts of the study area.

Another part of the report deals with the chemistry of formation waters, including shallow potable groundwater. The various hydrochemical trends discovered suggest that the Cooking Lake-Beaverhill Lake-Watt Mountain aquifer is in the northeast-oriented regional flow regime and that the overlying Ireton Formation aquitard isolates it from the northward-oriented flow regime in the Canmore Tongue, Grosmont Formation and Wabamun-Winterburn aquifers, which appear, from their hydrochemistry, to be part of the same system.

The three Cretaceous aquifers studied exhibit similar hydrochemical patterns with apparently more subdued effects of the Grosmont Formation drainage system in the upper aquifers due to the intervening Clear water Formation and Joli Fou Formation aquitards.

Part 4 of the report describes the techniques used to evaluate the flow regime.