Abstract: The total salinity of produced water of station 42# of the ninth area in the 1st oil production factory in Zhongyuan oil field is high.The contents of SO₄^2- and HCO₃^- of produced water of Wence well 215-5 are 1734mg/L and 2343mg/L respectively,the content of Ca²⁺ of Wen well 215-10 produced water of Wen well 215-10 is 12600mg/L; the contents of ions of Wen well 215-2 and Wence well 215-4 are complicated.The results of prediction and compatible experiment indicate that produced water from the station is mixed,it will format inorganic scales.The most component is CaSO₄ hydrate by Xdiffraction analysis,as the result of the high content Ca²⁺ and SO₄^2-in the mixed system and supersaturation CaSO₄.The inhibitor CD-1 is optimized according to static state experiment which is suitable to the produced water from the station,and the scale inhibition effectiveness is good at pH 5～7.The inhibition rate is 97.2%,when the inhibitor CD-1 and adjuvant is at 200mg/L and 0.5‰ respectively,and it is not emulsified.The dynamic experiment shows that the inhibition rate is above 95% at the amount of inhibitor;field application shows that there is not format inorganic scale when produced water of 4 wells and 10 wells are gathered,which effectively solves the scaling problem at working sites.

Key words: Zhongyuan Oilfield, scale inhibition, gathering system, inorganic scale, highly total salinity