Water production is a serious threat during oil production. Cross-linked polymer gels have been used for water shut-off in petroleum production operations for a long time and have proved to be one of the most effective methods. The organically cross-linked polymer gels have longer gelation times, are more stable, and can be applied at higher temperatures and over a wide pH range, as compared to inorganically cross-linked gels; hence, they are more preferable. The gelled polymer treatments can be applied to both injection and production wells to modify the permeability and alter flow in reservoirs to reduce water production and enhance oil production. The work presented involves the investigations on the performance of a hydroquinone/hexamethylene tetramine cross-linked polyacrylamide system. The study involves the detailed in-situ gelation mechanism of the above system by means of sand pack core flooding. The performance and efficiency of this polymer system in an oil field for enhancing oil recovery applications has been judged from these core flooding experiments.