Preparation and performance of oil well cement fluid loss additive ANAFM

Abstract

The organic/inorganic fluid loss additive was prepared by using silane coupling agent KH-550 modified nano silica as auxiliary material and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), N-vinylpyrrolidone (NVP), Acrylamide (AM), Fumaric acid (FA) as the comonomer. The ideal reaction conditions of the copolymer were confirmed to be the reaction temperature was 65 °C, the reaction time was 6 h, the mass ratio of AMPS/AM/NVP/FA was 4:4:1:1, and the amount of initiator was 0.36 wt%. Fourier transform infrared (FTIR) spectroscopy and thermogravimetry-differential thermal analysis (TG-DTA) were used to characterize the resulting copolymer, and its morphology was studied. TG test results confirmed that the copolymer has good thermal resistance, which can be found at 229 °C to maintain the thermal stability of the macromolecular chains; GPC results indicated that the number average molecular weight (Mn) of the polymer was 11.08 × 10⁴ g/mol, the fluid loss additive ANAFM has good filtration performance, and the API filtration of oil well cement is 46 mL at 130 °C with 5% ANAFM. The scanning electron microscopy (SEM) results show that ANAFM could adsorb on the surface of cement particles to form a hydration layer, which prevented leakage of oil well cement slurry.

Graphical Abstract

Keywords:

• Copolymer
• fluid loss additive
• nano-SiO₂
• oil well cement slurry

Acknowledgments

All authors are thankful for their financial support, and authors also want to acknowledge the scientific assistance of Advanced Cementing Materials Research Center (SWPU, China).

Additional information

Funding

The authors would like to acknowledge the financial support by the National Natural Science Foundation of China [51874254] and the CNPC Science and Technology Project(2020A-3913).