An effective salt-tolerant fluid loss additive-suitable for high temperature oil well cement

In this article, high temperature resistant and salt-tolerant fluid loss additive (FLA) is synthesized by aqueous free radical copolymerization of terpolymer comprising sodium p-styrene sulfonate (SSS), N-hydroxymethyl acrylamide (HAM), and itaconic acid (IA), and then evaluated as FLA (SSS/HAM/IA) in oil-well cement. Based on thermogravimetric analysis and fluid loss of experiments, it is found that the SSS/HAM/IA exhibits good temperature resistance and fluid loss performance, and can be used in temperatures ranging from 30 to 180 °C. Under the condition of 120 °C, using 6% SSS/HAM/IA ensures that the API fluid loss of saturated brine cement slurry systems is less than 50 mL, and strong salt resistance is retained. This is due to the cross-linking properties of the HAM molecule, which causes the terpolymer to exhibit a cross-linked structure, improving SSS/HAM/IA fluid loss ability.