Optimized Selenium‐Doped Nanocomposites for Enhanced Polymer Gel Performance in Permeability Reduction

Excessive water production in mature oil fields necessitates robust shut‐off treatments, yet conventional polymer gels often fail under high‐temperature and high‐salinity conditions. This study aims to enhance gel thermal stability and mechanical strength by incorporating selenium‐doped Ag/AgO–ZnO nanocomposites synthesized via a novel green route using Pinus nigra pollen extract. The nanoparticles were characterized using XRD, SEM, and UV–Vis spectroscopy, then formulated into HPAM/Cr(III) gels to evaluate rheology, syneresis resistance, and plugging efficiency in sandstone cores. Results indicated that 500‐ppm nanocomposite loading provided an optimal gelation time of 10 h and reduced water loss (syneresis) to ≤ 3% after 2 months, compared with 70% for the unmodified control. Rheological tests confirmed a significantly higher storage modulus and broader viscoelastic range. Most notably, core flooding experiments yielded a residual resistance factor (RRF) exceeding 3200, an order‐of‐magnitude improvement over the nano‐free baseline (RRF = 20). In conclusion, this eco‐friendly nanocomposite gel system offers a highly durable, efficient solution for deep‐reservoir conformance control operations.