Sour Service Domains of 13Cr Martensitic Stainless Steels: A Review of State-of-Art Knowledge vis-à-vis ANSI/NACE MR0175/ISO 15156

Abstract

Hydrocarbons, water, carbon dioxide, hydrogen sulfide, chloride, high temperatures, and pressures are all involved in oil and gas production. Thus, corrosion, particularly sulfide stress cracking (SSC), poses a great threat to the integrity of well components such as tubing, casing, packer, and wellhead assembly. Sometimes, SSC can lead to catastrophic failures and must be addressed due to operational security and environmental concerns. Localized corrosion, including SSC, can be reduced greatly with the appropriate material selection and optimization of critical operational parameters. The material selection is performed according to service environments vis-a-vis mechanical/ metallurgical attributes of the alloys as prescribed in standards such as API 5CT and ANSI/NACE MR0175/ISO 15156. Currently, corrosion-resistant alloys (CRAs) such as martensitic and duplex stainless steels, nickel, titanium and other precipitation hardened alloys are available and used in oil and gas industries because of their superior mechanical and corrosion properties. Owing to the operating environmental reasons, designer often opt for more expensive CRAs as compared to relatively less expensive materials which fall close to the performance boundary of materials selection criteria, thereby increasing overall cost of crude oil production. Thus, there is a paramount requirement to ascertain the candidate materials appropriately without bearing the cost penalties of over-specifications or the performance shortfalls of under-specified alloys when new fields are discovered. In this paper, the application domains of 13Cr martensitic stainless steels are reviewed vis-a-vis limits prescribed in ANSI/NACE MR0175/ISO 15156 standard. The paper will aid in the selection of cost-effective materials for oil and gas production when temperature, pressure, hydrogen sulfide concentration, pH, and salinity vary in different directions and cannot be well defined within standard limits.