TY  - EJOU
AU  - Wu, Boxuan 
AU  - Li, Mei-Chun 
AU  - Ding, Yang 
AU  - Liu, Chaozheng 

TI  - Preparation and Application of Polystyrene Microspheres as Plugging Agents in Water-Based Drilling Fluids
T2  - Journal of Polymer Materials

PY  - 
VL  - 
IS  - 
SN  - 0976-3449

AB  - Severe fluid loss in fractured formations remains a critical challenge in drilling operations, often leading to wellbore instability and increased non-productive time. Conventional plugging materials typically suffer from limited size adaptability and insufficient sealing efficiency under high-temperature conditions. To address these challenges, this study developed a plugging agent based on polystyrene microspheres (PSMs) via dispersion polymerization, using polyvinylpyrrolidone (PVP) as a dispersant. By tuning the molar ratio of PVP to styrene monomer, PSMs with controllable particle sizes (0.12–1.34 μm) were successfully synthesized. The results indicate that PSMs prepared at a PVP/SM molar ratio of 0.01, with an average particle size of ~0.28 μm, exhibited optimal plugging performance. Through a synergistic bridging-filling mechanism, these microspheres reduced the invasion depth into sand beds by over 40%. The addition of 2 wt% PSMs decreased the API fluid loss of the drilling fluid from 25.0 mL to 17.0 mL after aging at 120°C for 16 h, while simultaneously forming a denser filter cake. Furthermore, the incorporation of PSMs significantly enhanced the cuttings suspension capacity of the drilling fluid. This study provides a promising strategy for designing high-performance plugging agents for formations dominated by micro-fractures.
KW  - Drilling fluid; fractured formation; plugging agent; polystyrene microsphere; fluid loss

DO  - 10.32604/jpm.2026.086454