Hydrophobically Modified Acrylamide Hydrogel Particles for Conformance Control: Synthesis, Characterization and Enhanced Oil Recovery Performance

ABSTRACT As global oil reserves diminish, efficient hydrocarbon extraction from mature, heterogeneous reservoirs demands advanced polymer‐enhanced solutions. High water cut and poor sweep efficiency limit conventional water flooding, necessitating innovative enhanced oil recovery (EOR) strategies. This study explores hydrophobically modified hydrogels as preformed particle gels (PPG) to improve conformance control by selectively plugging high‐permeability zones. Acrylamide (AAm)‐based copolymers, functionalized with hydrophobic moieties (e.g., octadecyl acrylate (ODA) and lauryl acrylate (LA)), form physically cross‐linked networks via self‐assembly in aqueous solutions. These polymers exhibit superior viscosity, salinity tolerance, and thermal stability under reservoir conditions. FTIR spectroscopy confirmed the hydrogel structure, while swelling tests demonstrated resilience in high‐salinity (≥ 20,000 ppm) and high‐temperature (≥ 80°C) environments. Mechanical analysis revealed exceptional flexibility, with compressive strength up to 25 kPa and Young's modulus values of 235 to 550 Pa, ensuring durability under shear. Sand pack experiments simulating heterogeneous reservoirs highlighted the efficacy of fine PPG particles. Hydrogels [AAm‐ODA] 15% and [AAm‐LA] 15% reduced water permeability by factors of 6 and 12, respectively, outperforming conventional HPAM (hydrolyzed polyacrylamide)/Cr(III) systems. The tunable rheology and injectability of these PPGs offer a scalable solution for improving displacement efficiency while minimizing water production. By integrating polymer science with EOR, this work advances functionalized hydrogels as robust, adaptable tools for challenging reservoirs, emphasizing their potential to extend the lifecycle of mature fields through targeted conformance control.