In selecting materials for corrosive sour oil field environments, both age-hardened and cold-
worked solid solution nickel-base alloys offer many advantages such as high-strength, toughness and excellent corrosion resistance. Alloy 028 (UNS N08028), alloy 825 (UNS N08825), alloy G-3 (UNS N06985), alloy 050 (UNS N06950) and alloy C-276 (UNS N10276) are among the primary solid solution high nickel CRA's currently used in the cold worked condition for OCTG's and mechanical tubing in sour gas wells. A comparison of corrosion resistance of these nickel-base alloys for applications in severe sour service is presented. Many commercially significant alloys are ranked as to corrosion resistance up to 230°C (450°F) depending on the chloride concentration and H2S content.
Natural gas still remains one of the world's most abundant sources of energy. In the past, drilling and production tubulars were only steel, while stainless steels and nickel alloys were used primarily for valves or instrumentation. Today high strength, Corrosion Resistant Alloy (CRA) mbulars made from nickel alloys are needed because of:
1. Deeper wells involving higher temperatures, up to 230°C (450°F), and higher pressures.
2. Enhanced recovery methods such as steam injection, carbon dioxide injection and fire flooding,
and water flooding with seawater.
3. Increased weight reduction considerations, especially for offshore.
4. The need for greater corrosion resistance in sour wells containing hydrogen sulfide, carbon
dioxide, elemental sulfur, and chlorides.
