| abstract |
A method for enhanced oil recovery in an oil-bearing formation having high permeability zones, constituting preferential passages for the injected liquid, involves blocking the preferential passages by injecting into the formation an aqueous solution based on water soluble polymers at a concentration such that the viscosity of the aqueous solution is higher than the viscosity of the oil. Once the blocking step is completed, an aqueous solution is injected having an identical composition to that used in the blocking step, but at a lower polymer concentration. |