Preparation of epoxysuccinic acid copolymer and its performance as an inhibitor of barium sulfate scaling

A scale inhibitor EAHP has been prepared by reaction of an epoxysuccinic acid-acrylic acid-hydroxypropyl acrylate copolymer with 2-phosphonobutane-1,2,4-tricarboxylic acid and its performance as an inhibitor of barium sulfate scaling has been investigated.The optimum performance was obtained for the following synthesis conditions:monomer weight ratio m ESA ∶ m AA ∶ m HPA ∶ m PBTCA =1∶0.5∶0.5∶0.5,0.3% catalyst,temperature of 88-93 ℃,and reaction time of 4 h.When the dosage of inhibitor EAHP was 15 mg/L or greater,the scaling inhibition of barium sulfate reached 100%,a much better performance than other common scale inhibitors,suggesting that it offers a practical solution to the problem of barium sulfate scaling occurring during oil production.The mechanism of scaling inhibition was investigated.It was concluded that it is difficult to attribute the excellent inhibitive effect on barium sulfate scaling to chelation and lattice distortion and it may instead be due to the combined interaction of carboxyl,hydroxyl and aether groups.