The compatibility of neat chemicals when exposed to capillary and umbilical materials during injection is key to the smooth operation of chemical treatment programs in the oilfield and can be catastrophic if a failure occurred in an umbilical string during deepwater operations. The requirement of low viscosity for chemical injection through capillary strings and umbilicals make methanol the solvent of choice in many cases. Products formulated with methanol that contain chlorides and a low amount of water (less than 5 wt. %) frequently hinder the ability of stainless steels and corrosion resistant alloys to repassivate. This work describes the development of a synergistic combination of two additives that dramatically improve both the breakdown and the repassivation potentials of such materials as UNS S31603 and UNS S31803. Most of the experiments were conducted using cyclic potentiodynamic polarization (CPP) on neat chemicals and verified using long-term neat chemical exposures (90 day) to various materials to verify the CPP results.

Subject
Chemical compounds, Materials, Additives, Repassivation, Derivatives, Repassivation potentials, Polymers, Current densities, Amines, Pitting, Stainless steel, Cations, Electrode potential
Keywords:
Localized corrosion, inhibition, synergistic additives, cyclic polarization
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2019
Association for Materials Protection and Performance (AMPP)
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