A STUDY OF CORROSION INHIBITORS FOR THE PREVENTION OF PREFERENTIAL WELD CORROSION OF HIGH STRENGTH STEEL IN OIL FIELD ENVIRONMENTS

摘要

In petroleum production, carbon dioxide corrosion of steel pipelines is often most severe at or around welds. Changes in the chemical and metallurgical microstructure of the weld and heat affected zone (HAZ) compared to the parent metal, can result in galvanic and preferential corrosion of the weld or HAZ. Disruptions in flow can also result in corrosion of the parent metal and/or weld metal. This paper covers techniques developed in-house, involving potentiometry, weight loss and galvanic current measurements to determine the ability of corrosion inhibitors to prevent preferential and localised corrosion at welds. The dual cylinder working electrode is a particularly useful device for carrying out galvanic current measurements.