Method for improving aquifer remediation using in-situ generated nitrogen foam

A method for remediation of a water-bearing formation comprising the steps of:

• introducing a first aqueous solution and a second aqueous solution into the water-bearing formation such that the first aqueous solution and the second aqueous solution intermix within the water-bearing formation;
• and
• maintaining the intermixed solution in the water-bearing formation such that a foam is generated in situ;
• where the intermixed solution comprises a foaming agent;
• where the first aqueous solution comprises a nitrogen-containing compound and an acid;
• where the second aqueous solution comprises a nitrite-containing compound;
• where the concentration of the acid in the first aqueous solution is such that the pH of the intermixed solution in the water-bearing formation is at or less than about 4.5;
• and
• where the apparent viscosity of the foam generated in the water-bearing formation is in a range of from about 10 times to about 1000 times greater than an apparent viscosity of an aquifer remediation fluid as measured at 60° C. at a low shear rate in a range of from about 10 to about 50 RPM.