A general approach to evaluating sedimentary basins for CO2 disposal i
s presented in this paper. The approach is exemplified for the case of
the Alberta Basin in western Canada where a wealth of geological and
hydrogeological data from more than 150,000 wells drilled by the oil i
ndustry allows for a proper estimate of the basin potential for long-t
erm storage of CO2 captured from fossil-fuelled power plants. Geochemi
cal and hydrogeological analyses of CO2 interaction with the aquifer w
ater and rocks, and of CO2 transport in miscible and immiscible phase
by the natural flow of aquifer water indicate that, besides stratigrap
hic trapping, two additional mechanisms are available for the capture
and long-term retention of CO2 in the subsurface. One mechanism is min
eral trapping through precipitation of carbonate minerals when CO2 is
injected into basic siliciclastic aquifers. The other mechanism is hyd
rodynamic trapping when the residence or travel time of CO2 in low per
meability regional aquifers is of the order of thousands to a million
years.