Preparation and Application of Cellulose-Based Thermosensitive Polymer in Water-Based Drilling Fluid

The temperature-sensitive plugging agent (HAAN) was synthesized via free-radical graft polymerization using hydroxypropyl methyl cellulose (HPMC), acrylamide (AM), 4-acryloylmorpholine (ACMO) and N-vinyl-2-pyrrolidone (NVP) as the main monomers. HAAN demonstrates potential for addressing the frequent lost circulation problems encountered during the drilling of complex formations. The target product was characterized by FTIR and 1H NMR. Its phase transition behavior was verified via temperature-dependent UV-visible transmittance measurements and high-temperature rheological tests. The experimental results show that the plugging agent possesses good temperature and salt tolerance, and its rheological properties can be enhanced by incorporation into drilling fluid. It demonstrates effective plugging performance both at room temperature and under high-temperature conditions, thereby contributing to improved wellbore stability. It provides a new idea for green multifunctional application of cellulose in water-based drilling fluid.