H2S-CO2 mixture corrosion-resistant Fe2O3-amended wellbore cement for sour gas storage and production wells

The cement sheath used in H2S-CO2 mixture gas storage and high-temperature and high-pressure (HTHP) production wells is easily corroded; thus the cement has strict requirements for corrosion-resistant properties. In this work, a new additive, HTHP-CRA, was used to improve corrosion-resistant properties of Fe2O3-amended cement by reducing the original permeability and the generation low-Ca/Si hydration products. The experimental results indicate that the addition of HTHP-CRA to cement can slightly increase the original compressive strength, significantly reduce the original permeability and CH. The additive can also react with high-Ca/Si hydration products to generate low-Ca/Si hydration products such as xonotlite and tobermorite. Moreover, the addition of HTHP-CRA remarkably weakens leaching and corrosion effects by reduce CH during the corrosion process.