New Corrosion Inhibitor Reduces Overboard Oil in Water and Maintains Asset Integrity

Abstract

A new corrosion inhibitor that can reduce oil in water (OIW) was selected for use in a field offshore on Australia's North West Shelf. The selected product has allowed the achievement of the new stewardship OIW target of 17.5 ppm, enabling improvements in overall environmental impact. Laboratory tests showed that the selected product had similar corrosion inhibitor performance to the incumbent field product. Meanwhile, laboratory OIW measurements showed that 50 ppm of the selected product generated significantly less OIW (17 ppm OIW compared to 159 ppm OIW with 50 ppm of incumbent product). On-site tests were then performed with fresh produced fluids, demonstrating again that the selected product resulted in lower OIW (a 42%, 43% and 73% OIW reduction compared to incumbent product, at 20, 30 & 40 ppm of corrosion inhibitor, respectively). A full-field trial immediately demonstrated a decrease in OIW results corresponding to a decrease in overboard OIW from a daily average of 20.0 ppm to 8.8 ppm during the trial period, with no adverse impact on corrosion probe readings. The new product has now been in use on this facility for 10 months. Corrosion monitoring continues to show good inhibition while the OIW levels remain below 16 ppm average, and concurrently is allowing a reduction in the use of associated water treatment chemicals, further benefiting the environment.