Effect of transition rate and propargyl alcohol concentration on the corrosion of carbon steel during transitions in fluid composition from inhibited hydrochloric acid to sodium chloride brine

A newly developed flow cell technique is used to determine the progressive corrosion rate behaviour of carbon steel during concomitant changes in HCl and propargyl alcohol inhibitor over time, analogous to that experienced during matrix acid flowback. The corrosion response was found to be largely independent of fluid transition rate. Increasing initial inhibitor concentration supressed the overall corrosion rate with two peaks in corrosion rate being observed during every dilution process; the first peak relates to a critical propargyl alcohol concentration and the second to a critical HCl molarity. Such behaviour is discussed in the context of polymeric film formation/inhibition mechanisms.