Effects of chloride content on CO_2 corrosion of carbon steel in simulated oil and gas well environments

摘要

Effects of chloride content on CO_2 corrosion of carbon steel have been studied by immersion tests and electrochemical measurements combined with scanning electron microscopy, X-ray diffraction and analysis of polarization curves. Results show that maximum CO_2 corrosion rate is reached with increasing Cl~- content at a constant temperature and partial pressure. CO_2 corrosion is a mixed-controlled process, i.e., both activation and mass-transfer steps with increasing Cl~- content. Increasing Cl~- content can reduce CO_2 solubility. Moreover, Cl~- can destroy corrosion product films and change morphology of corrosion product films, but it has no effect on the composition of the corrosion product.