Corrosion rate of hydrogenation to C110 casing in high H₂S environment

Abstract

The corrosion behavior of C110 bushing at high temperature and high pressure with a high H₂S/CO₂ was studied, and a basis for the materials selection of sour gas well bushing was provided in H₂S, CO₂ and saline coexisting environment. Under acidic condiction, hydrogen atoms greatly entered into the material and caused the material properties changed. Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment. PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated, hydrogen charging after reacting in autoclave. The corrosion product film was observed through SEM. The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time. Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film. A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix, but cracked holes which will accelerate partial corrosion of the sample were also observed.

Keywords

electrochemical hydrogen charging / H₂S/CO₂ / weightlessness / oil casing / electrochemical properties / high temperature and high pressure / acidic environment

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