Open Access

ARTICLE

Preparation and Application of Polystyrene Microspheres as Plugging Agents in Water-Based Drilling Fluids

Boxuan Wu¹, Mei-Chun Li^1,2,3,*, Yang Ding¹, Chaozheng Liu⁴
1 School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, China
2 State Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao, China
3 Shandong Key Laboratory of Oil and Gas Field Chemistry, China University of Petroleum (East China), Qingdao, China
4 Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, China
* Corresponding Author: Mei-Chun Li. Email:

Journal of Polymer Materials https://doi.org/10.32604/jpm.2026.086454

Received 30 May 2026; Accepted 22 July 2026; Published online 21 September 2026

Abstract

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.

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Keywords

Drilling fluid; fractured formation; plugging agent; polystyrene microsphere; fluid loss

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