This paper presents the results of numerical modelling carried out to investigate the application of polymer-gel barriers for remediation of CO 2 leakage through faults or fracture zones in the caprock. The chemical flooding reservoir simulator UTCHEM was used for polymer-gel injections and assessment of the area of influence. Sensitivity analyses were performed to account for the effect of other crosslinkers other than chromium on the kinetics of gelation process. Subsequently, a numerical model of a saline aquifer was setup to carry out the reservoir simulations of CO 2 injection into a storage reservoir using Schlumberger's Eclipse 300 (E300) software. The amount of CO 2 leaked into a shallower formation through a sub-seismic fault was monitored and CO 2 injection was temporarily stopped for leakage remediation. The injection of polymer-gel solution was simulated and the area of influence and volume of polymer-gel needed were estimated for a number of scenarios. CO 2 injection was then resumed and the efficiency of the polymer-gel treatment was assessed for each scenario.