To achieve the effective scale removing technology in water-gathering pipelines,the scale of pipelines and ionic composition of produced water at L95 production sites in Linpan oilfield were analyzed. The interaction between Ba~(2+)and Sr~(2+)of produced water and scaling mechanism in scaling process was studied. The results showed that the scale was composed of barium sulfate and strontium sulfate in molar ratio 1∶1. The produced waters from five wells were rich in Ba~(2+)and Sr~(2+),such as L95-1 and L95-...