Effect of Fe~(2+) on the apparent viscosity of polymer solution and controlling methods

The influences of Fe2+on the apparent viscosity of polymer solution have been studied in this paper,and the results showed that a small amount of Fe2+would make the polymer degraded severely.HPAM polymer molecular weight and viscosity declined dramatically with the increasing of CFe2+among the 0~0.5mg/L,and declined slowly when the CFe2+above a concentration of 0.5mg/L.The AFM photos also showed that polymer network structure was destroyed largely.In order to ensure the polymer viscosity,the contents of Fe2+in preparation water should not exceed to the concentration of 0.5mg/L.There are several controlling measures used to remove Fe2+in preparation water,such as oxygen exposure,chemical complex method and manganese sand filtration.Chemical complex method is the most simple and effective one among them.The high effective iron removal reagent BHCT-1with a concentration of 300mg/L showed agood effect to remove Fe2+.For example,it was applied in offshore polymer flooding oilfield, and the viscosity of polymer solution would be increased by more than 20%.