Which material is most widely used in oil field water injection systems

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In oilfield water injection systems, low-alloy high-strength steel (including modified low-Cr corrosion-resistant steels such as 5Cr) is the most widely used corrosion-resistant material; at the same time, ordinary carbon steel coated with epoxy anti-corrosion coatings also accounts for a very high proportion of usage. Such materials offer good mechanical properties and basic corrosion resistance, while their cost is much lower than that of high-end corrosion-resistant materials such as pure stainless steel and nickel-based alloys. They are suitable for most conventional water injection applications. In China, major oil fields like Changqing have widely adopted 5Cr low-alloy corrosion-resistant steel; its corrosion rate is only half that of ordinary N80 steel, and its service life can exceed 10 years. It represents a preferred choice that balances corrosion protection efficiency with economic viability. At the same time, non-metallic corrosion-resistant materials such as rigid polyvinyl chloride, as well as bimetallic composite pipes, are also widely used in some branch lines and special pipe sections; however, their overall application scope is far smaller than that of the low-alloy high-strength steel systems.