The goal of this study was to simulate oxygen (O2) contamination and determine its impact
on an aqueous carbon dioxide (CO2) environment. The study used a quadratic model in a
surface response experimental design to determine the effects of oxygen and five other
variables on the corrosion of carbon steel in a CO2 environment. Surface response design
was used to optimize the number of tests needed to determine statistical significance of the six
experimental factors. Temperature (25 to 66°C), sodium chloride composition (0.1 to 1.0 wt%),
brine-hydrocarbon ratio (50 to 75 wt%), electrode surface preparation (media blasted or acid
etched), oxygen inhibitor concentration (0 to 100 ppm), and headspace oxygen level (100 to
10,000 ppm) were varied in a corrosion test design matrix. Separate from the corrosion
measurements, an oxygen sensor was used to measure the concentration of oxygen in the
hydrocarbon and brine phases. The oxygen measurements were compared to the corrosion
rate (CR) measurements to determine the effect of oxygen contamination on the corrosiveness
of the environment.
Key Words: oxygen, O2, contamination, carbon steel, carbon dioxide, surface response,
designed experiment