Saline aquifers of high permeability bounded by overlying/underlying seals may be surrounded laterally by low-permeability zones,
possibly caused by natural heterogeneity and/or faulting.
Carbon dioxide (CO2) injection into and storage in such ‘‘closed’’ systems with
impervious seals, or ‘‘semi-closed’’ systems with non-ideal (low permeability) seals, is
different from that in ‘‘open’’ systems, from which the displaced brine can easily escape laterally.
In closed or semi-closed systems, the pressure buildup caused by continuous industrial-scale CO2 injection may have a limiting effect on CO2 storage capacity