A New-Type Zinc Alloy Sacrificial Anode for Deep Well at Elevated Temperature

To control the external corrosion of TP110-3Cr casing of a 4 000 m depth well in an oilfield, a new-type zinc alloy sacrificial anode at elevated temperature was developed. Measurements of polarization curves and current efficiency of the anode show that at 80℃, polarization curve was relatively flat, open circuit potential quite negative and no potential reversal phenomenon was observed, the current efficiency reached 80%, its corrosion morphology was uniform and corrosion products easily falled off. In simulated water of the oilfield site, the corrosion protection performance of the new-type sacrificial anode was evaluated at elevated temperature. It can be concluded that the new anode can protect the casing material efficiently below 125℃, while at 130℃cracking phenomenon might appear and the anode can not be used.