Synthesis and application of temperature‐sensitive polymer as a novel plugging agent for water‐based drilling fluids

Abstract

Abstract In the process of drilling with water‐based drilling fluid, polymer plugging agent is very important to solve the problem of wellbore instability in the formation with micropores and microfractures. In this study, N ‐isopropyl acrylamide and 2‐acrylamide‐2‐methylpropanesulfonic acid were grafted onto the surface of SiO 2 modified by vinyl trimethoxysilane by reverse suspension polymerization reaction, and a heat‐sensitive polymer plugging agent was synthesized. The structure analysis showed that the synthetic material was the target product, with a particle size of 49.665 μm, high‐temperature resistance and sensitive temperature response behavior. According to laboratory evaluation experiments, it can be seen that the addition of the polymer increased the electrostatic stability of bentonite particles and had a chemical inhibition effect. Under the action of temperature and pressure, the synthesized temperature sensitive plugging agent formed a dense hydrophobic membrane on the surface of mud cake, which physically sealed the microcracks and pores, and reduced the filtration loss, so as to greatly improve the stability of shale. The experimental results showed that the synthesized temperature sensitive plugging agent has excellent high‐temperature resistance and plugging performance.