In this work, a compositional simulator (CMG-GEM) was employed to model the flow behavior of two components (CO2 and H2O) in the context of CO2 sequestration within a saline aquifer with infinite extent. A fluid model was built with the Peng Robinson EOS in a WINPROP and a base case model of limited extent aquifer with a range of volume modifiers assigned to boundary grid blocks as infinite was simulated. The amount of CO2 trapped, its maximum migration distance, and CO2 saturation distribution were analyzed for each of the aquifer volume considered. Pore volume modifiers of 103, 104, and 105 were sensitized. Results shows that saline aquifer of infinite extents complements the structural trapping of supercritical CO2 by limiting the ultimate migration distance of CO2 gravity currents. The quantity of trapped CO2 exhibited a rise as the pore volume of the boundary blocks increased from 100 (base case) to 103, 104, and 105.For the base case,volume multiplier of 103, 104, and 105, the volume of CO2 trapped were 59502925moles,88120568moles ,96803000moles, and 101404776moles showing an increase in moles as the volume increases. The base case model shows a CO2 lateral migration distance of 525ft along the aquifer length while pore volume of 103, 104, and 105 gives a lateral migration distance of 884ft, 985ft and 985ft respectively. The results indicate that the infinite volume effects have caused a dispersed distribution of CO2 trapped, contrasting with a concentrated distribution of mobile CO2 in a limited aquifer.