White Papers

The microstructure of cold hardened nickel alloys plays an important role in toughness, corrosion resistance and environmental cracking resistance.
If water is present in acid gases, the conditions may be very corrosive. Low alloy steels are commonly utilized in "dry" Acid Gas Injection wells that are designed to be "water free".
Corrosion resistant alloys rely upon the presence of a passive chromium oxide film on the surface to provide corrosion protection.
CO2 is the most common source of general corrosion in oil and gas production. In the presence of water, CO2 forms carbonic acid which is corrosive.
Galvanic corrosion occurs when two dissimilar metals are in contact in the presence of an electrolyte.
When handling austenitic, super duplex & nickel based alloys, special care should be taken to avoid contact with other non-corrosion resistant materials such as contaminated metal inspection tables, metal forks, chains, and cables.
H2S corrosion in the presence of tensile stress may result in catastrophic failure as a result of hydrogen embrittlement by mechanisms such as Sulfide Stress Cracking (SSC) and Stress Corrosion Cracking (SCC).
As completion designs get more complicated, and more reservoirs are completed at one time to reduce capital cost, proper zonal isolation becomes more critical. PBRs are one way of engineering zonal isolation by providing a receptacle for seal assemblies of any length.
Historically, high alloy downhole completion equipment has been manufactured from precipitation hardened “PH” nickel alloy bar stock. Often times, starting with bar, results in significant material loss, additional machining time and costs, and limitations to part lengths when compared to starting with a cold-worked nickel alloy tube.
Corrosion is a concern in the presence of water, especially in an offshore seawater environment where there is a higher potential for oxygen contamination.
Drilling hazards resulting from years of historical injection into shallower disposal zones and the necessity to comply with the growing requirements of all regulatory bodies to ensure safe disposal of oilfield brine are driving the need for more critical SWD wells (oilfield brine).
API 5CRA provides detailed testing requirements for satisfaction of the specification. The testing requirements vary by group, or alloy family. This article summarizes the testing requirements for Groups 2, 3 and 4.
API 5CRA serves as the leading industry standard for corrosion resistant alloy seamless pipe for casing, tubing, and coupling stock.
The document too frequently referred to simply as “NACE”, was first issued in 1975 by the National Association of Corrosion Engineers, now known as NACE International.
Paint-banding is an approved color code labeling method for quick identification of OCTG casing and tubing standardized by API 5CRA/5CT.
These up front planning considerations must be carefully thought out to ensure the correct OCTG material selection is made for full life of well production & injection integrity.
Corrosion resistant alloys are metals engineered to resist degradation by oxidation or other chemical reactions.
Without special care, corrosion may result from surface damage or contact that often occurs during storage or transportation.