The influence of water-soluble polymer solution on the flow behavior and oil recovery in areally heterogeneous reservoirs with adsorption and crossflow was investigated by numerical simulation. For the reservoirs of low viscosity oil, polymer floods had a relatively small improvement on the recovery of oil. Performances of water flood and polymer flood were not so sensitive to change in permeability variation up to sigma(1n k) = 1.0 Variations in permeability fields have a pronounced effect on the tertiary oil recovery efficiency for reservoirs with viscous oil due to additional dispersion caused by the randomly heterogeneous reservoir. Oil recovery increases as the correlation length in the permeability field increases for both water and polymer floods. An isotropic correlation length causes sudden changes in oil recovery and water-oil ratio and results in a significant decrease in oil recovery and increase in water-oil ratio over the production life.