Methods for improving oil recovery within a subterranean formation

A method for improving oil recovery within a subterranean formation, the method comprising:

• forming a barrier within a first region of the subterranean formation to isolate at least a portion of the first region from a proximate second region of the subterranean formation, where the first region comprises a greater permeability than the second region, forming the barrier comprising the steps of:
• introducing a first solution through a first conduit into the first region of the subterranean formation, the first solution comprising NH4Cl;
• and
• introducing a second solution, separate from the first solution, through a second conduit into the first region of the subterranean formation, the second solution comprising NaNO2, where:
• the first solution, the second solution, or both, further comprise a foaming agent;
• the molar ratio of NaNO2 to NH4Cl is from 1.5:1 to 3:1;
• the pH of a mixture of the first solution and the second solution is less than or equal to 4.0;
• and
• the ammonium containing compound and the nitrite containing compound react to generate nitrogen gas in the presence of the foaming agent to generate a foam within the first region of the subterranean formation, the foam providing the barrier;
• and
• introducing water into the subterranean formation, where the barrier diverts the water away from the first region and into the second region such that the water operates to displace at least a portion of a hydrocarbon present in the second region and discharge the hydrocarbons from the subterranean formation.