Corrosion Behavior of N80 and 3Cr Tubing Steels in CO₂ Flooding Environment

Corrosion behavior and characteristics of 3Cr and N80 pipelines steels and the inhibition efficiencies of three inhibitors were investigated by high pressure autoclave, scanning electron microscopy (SEM) and X ray diffraction (XRD) at various temperatures and CO2 partial pressures in simulated CO2 flooding environment. Corrosion rates and inhibition efficiencies of the samples were calculated and compared, and the surface morphology of corrosion product films was analyzed. The results indicated that, under the same CO2 partial pressure, the corrosion rates of N80 and 3Cr at 55 ℃ were larger than those at 30 ℃, the CO2 corrosion resistance of 3Cr better than that of N80. The main corrosion products were FeCO3 and a little Cr7C3 and Cr2C3.