Abstract
This paper evaluates the effect of seawater ingress on the corrosion behavior of L80-1Cr in an oil production environment. The seawater ingress has been simulated by changing the ionic composition of the produced fluid from formation water to injected seawater and by testing at temperatures that reflect the temperature decrease with time as more seawater is entering the production tubing. The composition of the two waters and the testing condition replicates the real field situations experienced by operators in the Danish sector of the North Sea. Experiments were carried out at ambient pressure in a three-electrode cell setup. The atmosphere constituted of pure CO2 at three different temperatures, namely: 40°C, 60°C, and 80. Linear Polarization and potentiodynamic sweeps were used to investigate the electrochemical behavior. The corrosion products and precipitates were analyzed using SEM-EDS. Calcium carbonate together with iron carbonate was the main product found in the corrosion scale, which influenced the morphology of the scale by making it more porous and brittle. Results suggest that the decrease in temperature, linked to higher water fraction in the production string, could be the factor that most significantly reduces the lifetime of the production string.
