Study on the Corrosion Law of Coiled Tubing in High CO2 Gas Field Environment in Sichuan

Aiming at the serious corrosion problem of coiled tubing operation in the gas field with high CO2 content in Sichuan，a high-temperature and high-pressure autoclave was used to simulate the working conditions of coiled tubing，and the corrosion rate of CT80 and 2205DSS tubing steel in CO2 environment was measured by weight loss method.In addition，the surface morphology and element composition of coiled tubing were analyzed by surface analysis techniques such as scanning electron microscopy (SEM)， X-ray diffraction analysis (XRD).Results showed that in the CO2-dominated corrosive environment， with the increase of temperature and pressure， the corrosion rate of CT80 in the gas phase environment gradually increased， the corrosion rate of 2205DSS had little change and was lower than that of CT80.The corrosion rate of CT80 in the liquid phase environment increased with the increase of temperature and pressure and then decreased， and the corrosion rate of 2205DSS was very low and changed little.Moreover， microscopic