Enhancing the filtration performance of an amphoteric polymer fluid loss agent with functionalized titanium dioxide nanoparticles

Abstract To address the problem of failure of fluid loss agents in high‐temperature and high‐salinity environments, this study introduced surface‐functionalized titanium dioxide nanoparticles as reinforcing agents to improve the poor control of fluid loss in current fluid loss additives for deep‐well and high‐salinity cementing. It employs 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS), acrylic acid (AA), and a cationic monomer (LAM) as synthetic monomers and uses in situ polymerization to develop a fluid loss additive (FLA) with effective heat resistance and salt tolerance. The as‐prepared samples were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric (TG) analysis. Furthermore, the heat resistance, salt tolerance, compressive strength development, and thickening performance of the FLA were evaluated. The results revealed that the FLA met expectations, with a minimal weight loss of only 3.38% at 302.5°C. It effectively controlled fluid loss in the cement slurry to within 50 mL at 90–210°C and 6.9 MPa, demonstrating excellent salt tolerance at a 4.0% FLA dosage. Potential mechanisms for controlling filtration loss have been proposed. Overall, this study introduces a highly effective fluid loss additive with superior heat resistance and salt tolerance for cement slurry applications. Highlights A novel fluid loss additive (FLA) for cement slurries is synthesized via in situ polymerization. The FLA is stable, with no significant weight loss up to 372.3°C. The FLA exhibited excellent temperature and salt resistance. The incorporation of FLA into the cement slurry results in the formation of a thin and dense filter cake.