H_2S CORROSION OF CARBON STEEL UNDER SIMULATED KASHAGAN FIELD CONDITIONS

摘要

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 H_2S and 10 bar CO_2. Flow loop experiments were performed at temperature of 25 and 80 deg 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 H_2S. 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.