KUSP1 is a polysaccharide that is derived from a particular bacterium that was discovered at the University of Kansas. Unique properties of KUSP1 were the incentive to investigate the application of this polymer for use in permeability-modification treatments. KUSP1 dissolves in alkaline waters but forms a gel as the pH of the solution is lowered to values below 10.8. Two methods to reduce the pH of KUSP1 solutions were studied. An ester was utilized to trigger gelation. Monoethylphthalate ester (MEP) reacts with water to produce an acid. The second method relied on the interactions between the alkali polymer solution and the rock material to reduce the pH. The performance of the KUSP1-MEP system and KUSPl-rock system was studied in several types of porous media.
A second property of KUSP1 is that it can be gelled in a time-delayed manner by the addition of boric acid. Performance of the KUSP1-boric acid system was studied in sandpacks and Berea sandstone cores.