Synthesis and Characterization of Biodegradable Terpolymer Scale Inhibitors

To address scaling issues in oilfield water injection, a degradable terpolymer scale inhibitor MA-AA-AMPS (terpolymer)was synthesized via aqueous solution polymerization using maleic anhydride, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid as monomers. Characterization confirmed the presence of carboxyl, sulfonic, and amide groups in the copolymer with good thermal stability. Scale inhibition tests showed that at 2% dosage, its scale inhibition efficiency exceeded 80%, remaining above 80% in the pH range of 3–8 and over 50% at 150 °C, with excellent tolerance to high-calcium environments. Biodegradation tests revealed BOD5/COD > 0.3, with a biodegradation rate exceeding 50% in 15 days and reaching 83.4% in 30 days, indicating environmental friendliness. This scale inhibitor effectively solves scaling problems in oilfield water injection systems.