TY - EJOU AU - Sun, Qiang AU - Qiu, Zheng-Song AU - Geng, Tie AU - Zhong, Han-Yi AU - Liu, Weili AU - Tang, Yu-Lin AU - Dong, Jin-Cheng TI - Application of a Hyperbranched Amide Polymer in High-Temperature Drilling Fluids: Inhibiting Barite Sag and Action Mechanisms T2 - Journal of Polymer Materials PY - 2025 VL - 42 IS - 3 SN - 0976-3449 AB - Addressing the critical challenges of viscosity loss and barite sag in synthetic-based drilling fluids (SBDFs) under high-temperature, high-pressure (HTHP) conditions, this study innovatively developed a hyperbranched amide polymer (SS-1) through a unique stepwise polycondensation strategy. By integrating dynamic ionic crosslinking for temperature-responsive rheology and rigid aromatic moieties ensuring thermal stability beyond 260°C, SS-1 achieves a molecular-level breakthrough. Performance evaluations demonstrate that adding merely 2.0 wt% SS-1 significantly enhances key properties of 210°C-aged SBDFs: plastic viscosity rises to 45 mPa·s, electrical stability (emulsion voltage) reaches 1426 V, and the sag factor declines to 0.509, outperforming conventional sulfonated polyacrylamide (S-PAM, 0.531) by 4.3%. Mechanistic investigations reveal a trifunctional synergistic anti-sag mechanism involving electrostatic adsorption onto barite surfaces, hyperbranched steric hindrance, and colloid-stabilizing network formation. SS-1 exhibits exceptional HTHP stabilization efficacy, substantially surpassing S-PAM, thereby providing an innovative molecular design strategy and scalable solution for next-generation high-performance drilling fluid stabilizers. KW - Hyperbranched polymer; barite sag; synthetic-based drilling fluids; performance evaluation; action mechanisms DO - 10.32604/jpm.2025.069808