In November 2005, participants at the Workshop on Geological Storage of CO2 at Princeton University agreed on the need for a common test problem to assess various models to simulate the fate of CO2 injected into the subsurface. Alberta Geological Survey offered to make available the data for the Wabamun Lake area in Alberta, Canada, which were assembled to develop a comprehensive model for studying CO2 geological storage. The Wabamun Lake area, southwest of Edmonton in central Alberta, was selected as the test area because a variety of favourable conditions identified it as a potential site for future, large-scale CO2 injection. Several large, industrial CO2 point sources are in the area, resulting in short transportation distances of the captured gas. Various deep saline formations with sufficient capacity to accept and store large volumes of CO2 in supercritical phase exist at the appropriate depth and are overlain by thick confining shale units. Most importantly, a wealth of data exist (i.e., stratigraphy, rock properties, mineralogy, fluid composition, formation pressure, information about well completions, etc.), collected by the petroleum industry and submitted to the Alberta Energy and Utilities Board. For these reasons, the Wabamun Lake area is an ideal location to characterize a CO2 storage site and analyze the potential risks.