Research on the corrosion behavior of floating bead low-density cement stone/P110 steel system under different CO2 pressure

This study investigates the corrosion state of the floating bead low-density cement stone/P110 steel system in simulated CO2-saturated formation water under high and atmospheric CO2 pressure. Results show that the resistance of the cement stone reaches a maximum value at 28 days and then decreases. The corrosion rate of P110 steel under high pressure is greater than that under atmospheric pressure. There is a certain gap and accumulation of corrosion products between the cement stone and the steel. Additionally, the maximum gap size and corrosion product thickness reach 27.5 and 67.69 μm, respectively. The composition of the corrosion products on the steel surface is mainly FeCO3, and the presence of the iron oxides are caused by oxidation. The corrosion products of the cement are also confirmed to be CaCO3 and a small amount of SiO2.