Research of the effects on the performence of scale inhibitor XY-1 for barium/strontium sulfate in wells

During the oilfields production,it is very common that scale exists in the well for temperature,pressure changing and chemical incompatibility.Especially barium and strontium scaling are difficult to remove.Thus,it affects seriously production and economic of the oilfields.According to the current situation of the sulfates scale inhibitor on the oilfield,a kind of ternary copolymer as a scale inhibitor was designed.The copolymer inhibitor was synthesized from maleic anhydride(MA),vinyllacetate(α-MAA) and methacrylate(MAC) through free radical polymerization in aqueous solution with the ammonium persulfate as initiator.The effects of synthetic conditions on the antiscaling properties were analyzed and the antiscaling properties of the inhibitor on the BaSO4 scale and SrSO4 scale were evaluated.The results showed that the optimum synthetic conditions were followed:molar ratio of MA,α-MAA and MAC 2 ∶1 ∶0.5,mass percentage of initiator 12%(based on the total mass of reactants),mass ratio of monomers to water 1 ∶2,reaction temperature 70 ℃,reaction time 7 h.In this way,scale-inhibiting efficiency of the initiator was up to 96% with the number of the initiator 24 mg/L.