Title : Understanding the scales formation Inhibition mechanism on C-Steel in a sour media
Corrosion control in sour environments is a serious challenge for oil and gas industry in dour media. One of the approaches to mitigate such problem is to use corrosion inhibitors (CI). The selection of a single or a mixture of CIs for a particular oil or gas production, transportation or storage facility depends on different parameters e.g. the ratio between carbon dioxide and hydrogen sulfide, pH, pressure, temperature, and brine chemistry where different kinds of iron sulfide and/or iron carbonate layers can be formed. To select the right corrosion inhibitor/s, it is highly crucial to understand the mechanism of corrosion of C-steel and its inhibition in H2S systems in absence and presence of CIs [1,2].
In this work, the electrochemical behavior of C-steel in (i) deionized water (DIW) and (ii) different NaCl solutions were examined in an H2S system. A series of experiments were conducted at different temperatures and two concentrations of inhibitors (A and B). The corrosion behavior of C-steel was investigated by measuring the open circuit potential (OCP), linear polarization resistance (LPR), and potentiodynamic polarization (PDP) in addition to scanning electron microscopy (SEM) coupled with an energy dispersive X-ray (EDX) besides Raman spectroscopy (RS). The results have shown that the corrosion rate of C-steel gradually decreased then stabilized with time in the inhibited solutions. The inhibition efficiency was found to increase in the presence of both types of inhibitors with temperatures. Surface analysis shows that no film of corrosion products existed. In fact, CIs controlled the corrosion process and prevented passive film formation (iron sulfide), even in the presence of H2S in all tests.
(a) understand the mechanisms and kinetics of sulfide scaling formation in sour oil and environment, and the effect of hydrogen sulfide on the electrochemical performance of iron-based materials,
(b) understand how to apply processes for characterization of the corroded surfaces (scale formation),
(c) establish meaningful experiments to measure the electrochemical kinetics of H2S corrosion,
(d) investigate the mechanisms by which corrosion inhibitors (CI) effect scale development and their ability to mitigate H2S corrosion.