Sour gas production in highly sour conditions has the potential to exhibit severe corrosion in
wells and flowlines within gathering systems. Often, this type of production occurs in high risk,
high consequence geographical locations. Consequently, integrity management programs for
these gathering systems have to be thorough and well implemented in their scope. Inhibitor
qualification, as part of an integrity management program and the inhibitor development
process has to include a severe enough test to adequately differentiate inhibitors. For highly
sour conditions, the test needs to evaluate localized corrosion whether it is due to pitting or
underdeposit conditions. This paper discusses the new sour gas test method development
and its use in evaluation of localized corrosion under highly sour conditions using an autoclave
set up to simulate low shear stress conditions. Inhibitors were evaluated in terms of maximum
and average pit depth penetration via statistical analysis of pits depth/size distribution using an
automated, high resolution vertical scanning interferometer in conjunction with an
electrochemical technique that monitors for localized corrosion. An example of an inhibitor
evaluation using the new test methodology was presented.