A multi-electrode array consisting of 24 carbon steel electrodes encased in epoxy has been used to evaluate inhibitors for control of underdeposit corrosion in the oil and gas industry. The electrode array enables examination of the effect of varying degrees of pre-corrosion during a single test and also statistical variation in electrode response. The array is mounted in a cup under sand (simulated field deposit) and coupled to an external carbon steel electrode in such a way that the galvanic corrosion current at each electrode can be monitored. The test method was demonstrated on two different inhibitors exposed to a simulated field brine under sweet (CO2) conditions. The adoption of the multi-electrode array highlighted the importance of statistical variations in determining the worst-case corrosion rate, which might otherwise not be identified in conventional tests.

Subject
Pits, Test methods, Inhibitor performance, Arrays, Sand, Corrosion rate, Precorrosion, Average corrosion rates, Corrosion inhibitors, Galvanic coupling, Deposit corrosion, Electrodes, Electrode potential
Keywords:
inhibition, underdeposit corrosion, multi-electrode
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2009
GOV
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