Microwave-synthesized composite preformed particle gels based on tragacanth gum and palygorskite for high-salinity high-temperature conditions

Abstract

Preformed particle gels (PPGs) emerged as promising materials for water management in mature oil reservoirs, particularly in heterogeneous carbonate formations characterized by high-permeability zones and fractures. In this study, hybrid composite PPGs were synthesized using tragacanth gum (TG), a biodegradable polysaccharide, grafted with acrylamide (AM) and crosslinked with N, N′-methylene bisacrylamide (MBA) in the presence of palygorskite (Pal) clay sourced from Qatar's Midra Shale. A microwave-assisted free-radical polymerization technique facilitated the rapid formation of gel particles with well-integrated organic-inorganic networks. Comprehensive characterization using XRD, XRF, FTIR, SEM, and TGA confirmed Pal's successful grafting, thermal reinforcement, and morphological integration into the PPG matrix. Swelling behavior in real Gulf seawater (TDS = 45,2 mg/L) and rheological measurements taken at elevated temperatures (80 °C and 100 °C) showed that the addition of Pal enhanced gel rigidity but slightly reduced swelling capacity, likely due to increased steric hindrance. The formulation TPAC₂ (2.5 g Pal) exhibited an optimal balance between swelling (14.2 g/g at 100 °C) and mechanical strength, making it a strong candidate for reservoir applications. These findings highlighted the potential of TG–Pal composite gels as environmentally friendly, thermally stable PPGs suitable for high-salinity, high-temperature conditions.