Greg Stark Consultancy

Technical Publications

Qualification of ERW/HFI Manufactured Pipe for Wet, Sour Crude and Gas Services

Excerpt:  API 5L pipe manufactured with the Electric Resistance Weld (ERW) or High Frequency Induction (HFIW) welding processes offers considerable cost saving to the end user in place of similar seamless or Submerged Arc Welded (SAW) pipe. Historically, such pipe has never been fully trusted for full application by the oil and gas industry due to catastrophic failures in the field. No universally recognized industry standard exists for qualification of manufacturers of ERW/HFI pipe, and there is no robust standard for promoting a high level of quality and reliability of such a product. Saudi Aramco learned first hand the impact of such lack of product reliability with 10 field failures during hydrostatic testing of a newly constructed pipeline. The experience resulted in significant project delay and cost over run.

 As a result of this experience, Saudi Aramco eventually developed an extremely comprehensive qualification and manufacturing specification for such pipe. The specification incorporates a statistically proven qualification procedure and a rigorous manufacturing process control regimen to maintain extremely high quality and mechanical properties of the ERW/HFI weld seam. At the same time, Saudi Aramco developed a proprietary computer program for the collection, manipulation, and reporting of qualification and production test data.  Currently four such pipe manufacturers in the world are approved to manufacture pipe in accordance with the new specifications. Because of the greatly increased reliability of pipe produced to the new specification, Saudi Aramco has been able to consider the use of ERW/HFI manufactured pipe in applications which were considered more critical. As projects begin to utilize this new approach Saudi Aramco will be able to realize as much as $100/ton savings in the future.


Updated:  11-23-08     webmaster


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