We Call This “Dream-Pipe”
GMC will begin the testing a prototype of 8” upset CRA 125Ksi pipe with connected ends.
The era of connected tubulars to a DNV/GL approved standard for a systemic application of subsea hydrocarbon transmission systems is coming to market. Previously, high strength steels had issues with sour service when welding and complying with NACE hardness requirements. The issue is carbon steels in service in the offshore and oil refinery industries are susceptible to a cracking mechanism known as sulfide stress cracking (SSC) or hydrogen stress cracking (HSC) when in sour service, ie when hydrogen sulfide (H2S) is present in the process fluid. Although the cracking is described as stress cracking, the main problem is the hardness of the parent metal, weld metal and heat-affected zone (HAZ).
“Dream-pipe” eliminates this problem because the welding process is eliminated. All tubes are manufactured with upset ends. The ends are CNC machined with a GMC mechanical connector, directly at the mill. Hence, a stronger pipe, with greater “sour service” capability will result.
The future will result with a completed 12-18m tube in high strength CRA material with upset ends. The upsets will be machined with connected ends, and insulation coating applied over the entire length for delivery direct to the work site.
Offshore, robotic tooling will connect these tubulars in less than 2 minutes with a lay rate of at least 200m/hr. One of the higher costs of deepwater development, SURF, will be reduced by at least 50%!