GALVANIC CORROSION AND INHIBITOR SELECTION BETWEEN 13Cr-L-80 STEEL AND N-80 STEEL

Steel 13Cr-L-80 and N-80 was selected as casing materials at Wenchang 13-1/2 oil field.The galvanic corrosion of the two materials in completion fluid was studied by static weight-loss method and the proper inhibitor was selected.The corrosion rate of 13Cr-L-80 increased and that of N-80 decreased at 60℃,indicating the taking place of galvanic corrosion.Corrosion inhibitor JC-6 selected out of 9 commercial chemicals added at dosage 1.5% decreased the corrosion rate of 13Cr-L-80 coupled with N-80 at 60 ℃ to 0.012 and 0.165 mm/a respectively;JC-6 and PA in various combinations could decrease the corrosion rate further and in mass ratio 9∶1 (notated as JCP-6) at dosage of 1.5% could decrease the corrosion rate of the two metals at 70 ℃ to 0.013 and 0.069 mm/a respectively.