Corrosion Behavior of 20 Steel in Simulated Working Environment of CO₂ Flooding

Corrosion tests of 20 steel in simulated working environment of CO2 flooding were carried out in high-temperature and high-pressure autoclave, the effects of temperature and CO2 partial pressure on corrosion rate of 20 steel were studied by weight loss method. The contents of calcium and magnesium ions before and after experiment were analyzed using ion chromatography, the corrosion morphology were observed by SEM, and the composition of corrosion scales were analyzed by XRD. The results show that 20 steel suffered from serious CO2 corrosion, the average corrosion rate increased gradually with the increase of temperature, and decreased first and then increased with the increase of CO2 partial pressure. The increase of CO2 partial pressure quickened the deposition of Ca2+ and Mg2+ in producing water, and the corrosion products were mainly composed of FeCO3.