If the internal corrosion of carbon steel onshoreand offshore pipelines can be understood better and investigated more, therewill be no need to use stainless steels and corrosion resistance alloys in so many cases. Oils and its derivatives should not be corrosive to metals but CO2 and H2S together with water can cause an intense corrosion problems. The extent of internal corrosion is also influenced by the temperature, pH, salts, flowrate, etc.
In this paper, it is tried to explain the causes of most common types of internal corrosion mechanisms in oil and gaspipelines such as CO2 corrosion, H2S corrosion, preferential weld corrosion, top of the line corrosion and hydrogen induced cracking using the example of an exploded natural gas pipeline in New Mexico in 2000 and in addition an introduction to DNVGL-RP-F116 “Integrity management of submarine pipelinesystems” is provided. It is also tried to represent some 'fitness for purpose' projects in which DNVGL has been involved where internal corrosion assessment have been investigated.
DNVGL-RP-F116 / Appendix C gives an overview of different corrosion threats commonly associated with submarine pipelines for oil and gas production, and applicable techniques for inspection of corrosion control systems and recommendations regarding corrosion monitoring.