Investigation of corrosion behavior of 2205 duplex stainless steel coiled tubing in complex operation environments of oil and gas wells

In this paper, the corrosion behavior of 2205 duplex stainless steel coiled tubing in acidizing and production environments was studied by high-temperature and high-pressure corrosion weight loss tests, stress corrosion cracking test, electrochemical tests, microscopic morphological analysis and corrosion product analysis. The results show that in the acidizing environment, the duplex stainless steel has high corrosion rates especially in the acidizing solution with high HCl con-centration, with the selective dissolution of ferrite phase. In the production environment con-taining CO2 and H2S, the duplex stainless steel has excellent resistances to corrosion and stress corrosion cracking. With the increase of pH value, the pitting potential and polarization resistance exhibit the increasing trend, indicating the better passivation performance. Therefore, 2205 duplex stainless steel coiled tubing can be recommended to be mainly used for the operations in production environment rather than acidizing operations.