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Understanding of reinforced elastomeric corrosion barrier ring (CBR) for oilfield tubular internal lining systems
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Fiberglass liners in downhole tubing have been used since the early 1970s. The technology was initially driven by the challenge to ensure longer lifetime of the tubing in injection wells. Glass Reinforced Epoxy (GRE) lining systems are made up of long, thin-walled glass fiber epoxy liner that is used as a corrosion resistant alternative for fluid transport, especially in applications where there is a presence of H2S, CO2, dissolved oxygen, brinish disposal water, highly acidic soil conditions and more. While liners protect most of the piping surface area from corrosion, it is critical to complete this protection at the vulnerable connection areas with a reinforced elastomeric corrosion barrier ring (CBR) for a completely corrosion-resistant tubing system. When a trained crew properly installs a lining system with CBRs, a fiberglass-lined pipe can last more than 20 years in the field without liner collapse and corrosion damage to the interior pipe. It is in the best interest of all parties involved with installation to ensure the CBR is the best available product with a history of reliable performance, and that proper installation procedures are followed to prevent product failure.

Proper Installation of CBRs is critical for overall success of oilfield tubulars:

CBRs should be compressed between the flares, located on each liner end, during the connection make-up process in order to protect couplings, which are highly susceptible to corrosion damage. In order to protect CBRs and ensure they are in proper compression during installation, reference bands should be marked on the pin ends to indicate the initial CBR contact and compression levels. Users have found that installation goes faster and smoother when the tubing arrives from the lining facility with the reference bands in place. In addition, it is important to use a stabbing guide to make certain that the tubulars do not clash together and cause damage that would compromise the protection provided by flares. Utilizing a stabbing guide reduces the chance of damage to the corrosion barrier at connection areas.

Duoline® Technologies CBRs, for use with API connections, are offered in two different oil resistant elastomers. The PC-CBR (nitrile rubber) is recommended for typical produced oilfield fluid applications. However, if concentrations of CO2 are significant, the HP-CBR (modified nitrile polymer) should be considered. The HP-CBR is a higher strength material that is more tolerant to blistering and explosive decompression associated with elastomers in CO2 service. For specifically designed Premium Connections, glass-reinforced PTFE Corrosion Barrier Rings are available. All Duoline® CBR’s are reinforced with spring steel wire, thus ensuring the CBR will stay in place during pressure cycles.


To ensure complete protection against corrosion and prevent possibilities of liner failure, reinforced elastomeric corrosion barrier rings (CBRs) should be properly installed at vulnerable connection areas to protect couplings.

Duoline® Technologies recommends the presence of a trained Duoline® technician when Duoline® is installed or repaired at the well site. A staff of qualified technicians is available at our Duoline® Technologies manufacturing facility. In addition, a number of service companies throughout the world have technicians who have been trained by Duoline® Technologies to run or repair Duoline®.

Duoline-20® and Duoline-350®, manufactured by Duoline® Technologies, are filament-wound, fiberglass-reinforced epoxy liners that reliably beat corrosion. Since 1964, more than 100 million feet of Duoline® liners have been successfully installed worldwide as a more robust alternative to plastic coatings, and as a high-performance, high-value, cost-effective alternative to Corrosion Resistant Alloys.

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