Experimental Study on CO2 Corrosion of Super 13Cr Integrated Tubing with Erosion Damage

Abstract

Integrated tubing can be used in the process of both fracturing and production for the oil and gas industry. During the process of fracturing, the inner surface of the tubing is subjected to the erosion from the slurry with sand and fracturing fluid, and then in the process of production, it is also corroded by the high-CO2-containing multiphase medium. To evaluate the CO2 corrosion resistance of Super 13Cr tubing after erosion in fracturing, the erosion test of Super 13Cr tubing under different impact angles was carried out by the jetting facility. For the samples with different erosion damage, the high-temperature and high-pressure CO2 corrosion experiments were carried out. The CO2 corrosion morphology with different erosion damage was also analyzed by SEM. The results show that different erosion damage at different impact angles can affect the corrosion rate in the later CO2 corrosion test. At an impact angle of 30°, the erosion damage is mainly caused by the cutting and plowing mechanisms by the eroded particles. The craters and folded extruded lips on the surface of the Super 13Cr tubing are formed and the passive film of super 13Cr is removed on the bottom of the craters, resulting in a corrosion rate that was approximately 1.4 times greater than that of the non-eroded surface. However, at the impact angle of 90°, the erosion mechanism is the plastic deformation and many platelets are formed. Less contact area between the fresh surface without passive film and the corrosive medium results in a lower corrosion rate than the material with 30° impact erosion damage.