ABSTRACT
This chapter introduces the offshore or marine environment as a place where a large number of oil and gas activities are taken place. The offshore environment is very corrosive due to the presence of seawater and chloride in the atmosphere. The offshore environment is divided into four zones: immersion, tidal, splash and atmospheric. The nature and corrosivity of each zone are discussed in this chapter. The basics of corrosion including four elements of anode, cathode, electrolyte and metallic path are explained in more detail. The most important part of this chapter is related to different types of external corrosion because of the marine environment such as general corrosion, pitting, crevice, galvanic, corrosion under insulation (CUI), chloride stress cracking corrosion (CLSCC) and hydrogen-induced stress cracking (HISC) corrosion. All these corrosion types, which are split into three categories of general corrosion, localized corrosion and environmental cracking corrosion, are explained in detail in this chapter.
