Resume
The Bureau of Mines has made laboratory tests of the relative merits of various steels and alloys for resisting the corrosion that occurs in high-pressure gas-condensate wells. The results of the tests indicate that a steel containing approximately 9 percent chromium would provide the best combination of corrosion resistance, physical strength, and cost economy of any of the steels tested. A steel containing 7 percent chromium would sustain less weight loss than the carbon steel now manufactured to meet API grade J-55 specifications for tubing and would not be subject to serious pitting corrosion. Laboratory tests indicate that a steel containing 9-percent nickel would not be subject to the severe pitting corrosion that is characteristic of the carbon steel tubing now used in wells and would be subject to lower rates of weight loss. Tests, made in the field, exposing coupons of metals in the flow-stream of wells have indicated that 9-percent nickel steel has relatively high resistance to corrosion by gas-condensate fluids.
The chromium - nickel stainless steels and copper-nickel alloys exhibit high resistance to corrosion. These metals could be used in the manufacture of special fittings provided the nature and distribution of the phases in the flow-stream permit the use of dissimilar metals in contact with one another.
