Evaluation of cracking and corrosion susceptibility in high pH scale dissolver CO2-containing environment
© 2014 by NACE International. A high pH scale dissolver to be used for cleaning gas lift valves (GLV) was evaluated to address corrosion and cracking concerns in offshore operations. Corrosion and stress corrosion cracking (SCC) tests at 120°C (248°F) using generic tubing (UNS S41000) and casing (UNS G41400) steels were performed to characterize and qualify use of this scale dissolver. The data showed that the presence of this chemical did not promote SCC of the UNS S41000 stainless steel or UNS G41400 carbon steel in slow strain rate tests (SSRT) or electrochemical tests. However, weight loss testing for 7 days in CO2saturated solutions and Electrochemical Impedance Spectroscopy (EIS) measurements with the chemical added, indicated very high general corrosion rates for both carbon steel (1450 mpy) and SS (225 mpy). It was recommended that this scale dissolver should not be used for this application.
author list (cited authors)
Mahajanam, S., Case, R., Cloke, K., Daniels, J., Dunn, J., & Bredal, F.