Study on Novel Hybrid of Polymer Gel and Silica/Alpha-Alumina Nanoparticles in Fractured Carbonate Reservoirs for Water Shut-off Applications

Water production is a critical challenge in fractured and high-permeability reservoirs where excessive water flow significantly reduces oil recovery. In previous studies, most evaluations of polymer gels as a water shut-off agent were mainly limited to the bulk systems, without deep insights into their behavior in fractured porous media. This paper aims to investigate the performance of a novel polymer gel system that employs sulfonated polyacrylamide/chromium(III) with silica nanoparticles (SNPs) and alpha-alumina nanoparticles(αANPs). Nanoparticles (NPs) were produced via a sol–gel route and were incorporated into the SPAM/Cr (III) gel matrix to assess their effect on the gel’s swelling response under formation-water conditions. Results demonstrated that the incorporation of SNPs into the gel structure improved its properties in terms of strength and thermal resistance, thereby improving the gel’s swelling capacity. Nevertheless, the use of alpha alumina NPs had a negative impact on the swelling characteristics of the gel. To further investigate the performance of the gels in a porous medium, flooding tests were conducted on three core samples with hydraulic fractures and one core sample with a natural fracture. Gels with and without NPs effectively reduced nonuniform permeability and exhibited significant swelling within the cores, and a high-performance polymer gel with optimized swelling capacity for field applications was proposed.