The Application of Mechanical-Chemical Corrosion Theory in Downhole Tubing CO2 Corrosion Research

Indoor simulating experiment is a main method for oil field CO2 corrosion research. Experimental parameters are very important for an accurate simulation. Based on the mechanical-chemical corrosion theory, the external load may be possible to accelerate the corrosion rate. However, the influence of N-2 pressure on CO2 corrosion during the simulating experiment is negligible. Because the coupon stress induced by additional N-2 pressure is very low, therefore, the N-2 adding procedure can be cancelled and a more safety working space for researchers will be created. However, it does not mean that mechanical-chemical corrosion influence can be ignored. For downhole tubing, the hoop stress generated from the formation compress or liquid column internal pressure is remarkable; stress effect on corrosion has to be taken into consideration. When pit cavity especially occurred on the internal tubing surface, the stress concentration effect will induce a much higher local stress. Mechanical-chemical corrosion will become significant and more study should be performed on this topic.