Effect of CO sub(2) and pressure on the stability of steels with different amounts of chromium in saline water

CO sub(2)-induced corrosion of casing and tubing steels is a relevant safety issue for compressing emission gasses into deep geological layers (CCS, Carbon Capture and Storage). The influence of CO sub(2) and pressure of the surrounding media on steels is demonstrated in laboratory experiments providing a corrosive environment similar to a geological onshore CCS-site in the Northern German Basin (T = 60 degree C, p = 1 - 100 bar, Stuttgart Aquifer, CO sub(2)-flow rate of 3 l/h, 700-8000 h exposure time). Corrosion kinetics and microstructures were characterized using specimens of heat treated 42CrMo4 (1.7225, casing) and soft annealed X46Cr13 (1.4034, tubing).