Effect of Temperature on CO₂ Corrosion Behavior of J55 Tubing

Some tests in a high-temperature and high-pressure autoclave at 25-65 ℃ were used to simulate the CO2 corrosion behavior of J55 tubing in Yanchang oil field environment, and the effect of temperature on CO2 corrosion behavior of the tubing was studied by scanning electron microscopy and X-ray diffraction. The results show that the average corrosion rate of J55 tubing increased dramatically with the increase of temperature, a fitting function predicted well the corrosion rate of J55 tubing at different temperatures. Increasing temperature quickened the deposition of Ca2+ and Mg2+ in corrosion scales, resulted in the present of double salt Fe(Ca,Mg)(CO3)2 at higher temperatures, changed the structures of corrosion scales, and thus led to serious under-deposite corrosion.