H2S Corrosion of Carbon Steel under Simulated Kashagan Field Conditions

Abstract

Abstract A series of flow loop corrosion experiments have been carried out to assess the unmitigated corrosion susceptibility of carbon steel exposed to simulated Kashagan produced fluid, consisting of chloride-containing brine in equilibrium with up to 30 bar H2S and 10 bar CO2. Flow loop experiments were performed at temperature of 25 and 80°C with flow velocities of 1, 3 and 5 m/s. General corrosion rates in the range of 0.5-2 mm/y were measured on all test specimens. High general corrosion rates above 20 mm/y without protective film formation are typically encountered in corresponding sweet systems without H2S. The experimental work also included characterisation of corrosion product films formed under these conditions. The corrosion product films consisted of various iron sulfides. Pitting corrosion took place at a flow velocity of 5 m/s, but not at 1 and 3 m/s.