Effects of CO2 and H2s on corrosion of martensitic steels in NaCI at low temperature

Ruishu Feng, Justin Beck, Derek M. Hall, Aysel Buyuksagis, Serguei N. Lvov, Margaret Ziomek-Moroz

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Corrosion studies were conducted for martensitic carbon steels in brine solutions at 4 °C and 10 MPa (1450 psi), which simulated the subsurface environments encountered in Arctic drilling. Three environments with a 5 % wt. NaCI brine were used: (1) 0.312 mole of CO2 per mole of H2O in brine, (2) 3.12 x 10-4 mole of H2s per mole of H20 in brine, and (3) a mixture of 3.12 x 10-4 mole H2s and 0.312 mole CO2 per mole of H20 in brine. Two martensitic carbon steels were selected for the investigations: A high strength low alloy (HSLA) carbon steel commonly used for drill pipe (G41000) and a newly designed ultra-high strength low alloy (UHSLA) steel (G41300). Electrochemical and mass loss measurements found corrosion rates on the order of 0.05 mm y1 in the systems containing H2s and CO2+H2s, while the CO2 systems saw corrosion rates between 0.5 and 2 mm y1. Surface analyses of the tested samples were performed using scanning electron microscopy and energy dispersive X-ray spectroscopy to identify corrosion products. The corrosion products were unstable and oxidized quickly after taking out of the system. All samples had a high oxygen content across the surface, though the samples exposed to H2s and CO2+H2s had relatively higher levels of sulfur present in an inner region of the film. Experimental corrosion rates were compared to model predictions, and a good agreement was found for the CO2 and H2s cases. However, the model predicted that corrosion rates in the mixed case would match those of the CO2-only system. The experimental results showed that CO2:H2s ratios as high as 1000 can result in predominantly sour corrosion at the low temperature, high pressure conditions tested.

Original languageEnglish (US)
Title of host publicationNACE International - Corrosion Conference and Expo 2016
PublisherNational Assoc. of Corrosion Engineers International
Pages3532-3544
Number of pages13
ISBN (Electronic)9781510821354
StatePublished - Jan 1 2016
EventCorrosion 2016 - Vancouver, Canada
Duration: Mar 6 2016Mar 10 2016

Publication series

NameNACE - International Corrosion Conference Series
Volume5
ISSN (Print)0361-4409

Other

OtherCorrosion 2016
CountryCanada
CityVancouver
Period3/6/163/10/16

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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