Effect of Mechanical Damage during Well Completion Activities on High Chrome Steel Tubulars in High H2S and CO2 Environments

摘要

High concentrations of H2S and CO2 make oil producing wells highly corrosive to normal steels alloys, such as carbon steel. The usual solution to this is high chrome steels alloys, such as ferritic stainless steel, i.e. 13Cr. These steels have a good service record in such environments, especially at operating temperatures below 150°C. However the passive film which provides protection can be easily damaged by mechanical activities such as wirelining. The lack of repassivation in these environments means that once damaged by mechanical action these tubulars suffer extensive localized corrosion. A comparison is made of the different workover methods which can exacerbate this problem, particularly wirelining. Where possible we recommend the use of coiled tubing.