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Permeability contrasts exist in multilayer geological formations under consideration for carbon sequestration. To improve our understanding of heterogeneous pore-scale displacements, liquid CO₂ (LCO₂)–water displacement was evaluated in a pore network micromodel with two distinct permeability zones. Due to the low viscosity ratio (logM = −1.1), unstable displacement occurred at all injection rates over 2 orders of magnitude. LCO₂ displaced water only in the high permeability zone at low injection rates with the mechanism shifting from capillary fingering to viscous fingering with increasing flow rate. At high injection rates, LCO₂ displaced water in the low permeability zone with capillary fingering as the dominant mechanism. LCO₂ saturation (S_LCO2) as a function of injection rate was quantified using fluorescent microscopy. In all experiments, more than 50% of LCO₂ resided in the active flowpaths, and this …