Internal corrosion control and material selection for pipes in sour and high-salty oil fields

With the development of sour and high-salty oil fields (p_H2S≥0.3 kPa, TDS≥10, 000 mg/L or Cl^-≥6, 000 mg/L) in the world, the working conditions for pipeline and piping become harsher, which propose higher requirements for selection of pipe materials. In this paper, internal corrosion in sour and high-salty oil fields is analyzed, indicating that pitting and cracking are the most typical types of failure. Based on the domestic and international standards as well as specifications of international oil companies (e.g. NACE, SHELL, ADCO, TOTAL and IPS), the control measures for internal corrosion are defined. The principles of material selection for pipes in sour and high-salty oil fields are proposed based on the failures of cracking and corrosion. At the same time, the material selection is considered based on the corrosion failure in two aspects of the corrosion volume and the corrosion medium of carbon steel in cycle life. Moreover, the basic process for selecting sour-resistant carbon steel and the application limits of corrosion resistant alloy (CRA) are determined. This paper provides reference and foundation for material selection of pipes in sour and high-salty oil fields.