Corrosion behavior of P110 steel in CO2-saturation solution with high concentration of Cl-and Ca2+ under high temperature and pressure

摘要

With the development of oil and gas resources, the formation water with high concentrations of Ca2+ and Cl− has put forward higher requirements for the safe service of tubular columns. In this study paper, the underground environment is simulated using high-temperature and high-pressure autoclave; electrochemical research results are combined; and the effects of Ca 2+ concentration, corrosion temperature, and corrosion time on the corrosion behavior of P110 steel in CO 2- saturation solution are analyzed. Research results show that the presence of Ca2+ promotes the acidification of the solution and accelerate the dissolution of the P110 steel. The trend of corrosion rate and Ca 2+ concentration in high-Cl-solution is a “V” curve. The highest corrosion rate of 2.2 mm/a occurs in 1080 mg/L Ca 2+ CO2-saturated NaCl solution. As the temperature increases, the corrosion rate of P110 steel decreases. The corrosion rate is approximately at a constant value above 120 ° C. In addition, higher Ca2+concentration in the solution increases the probability of pitting for P110 steel. For FexCa1-xCO3 compounds, no strict ratio is observed between Fe and Ca, and the shape of the product depends on the concentration of Ca2+ ions in the solution.