Corrosive Effect of Oil´s Accompanying Water polluted with H 2 S over Steel (API 5L X-52)

Abstract

The corrosion from the steel to the carbon in the sale oil pipage conduction, is a serious problem, due to the material and economical looses they cause, damaging even in some cases the productive field. The
purpose of this study is to determine the aggressiveness of the oil´s water layer, polluted with H2S(g), over the steel of pipelines´ construction (API 5L X-52), taking into account the temperature variations which take place during the transportation of the oil, using the electrochemical techniques of polarisation resistance (LPR) and electrochemical noise. It is pretended to determine the velocity of steel corrosion in the oil´s water layer polluted with H2S through electrochemical techniques. It was shown that the
temperature increases and the concentration of H2S to 500 ppm in the oil´s accompanying water emphasizes the corrosion phenomenon experienced by the steel (9, 188 0 mm/year to 70 °C).The results of the electrochemical noise spectrums and the values of the localisation´s index calculated, shown the presence of corrosion on the steel surface (API 5LX_52).This result was complemented through optic Microscopy which permits to corroborate the poor adherence of the sulphur layers deposited on the metal that increase the appearance of events found with the temperature increase and the concentration of H2S in the environment studied.
Key words: electrochemical corrosion, water layer, pipeline.