Full Content is available to subscribers

Subscribe/Learn More  >

Subsea Pipelines: The Remotely Welded Retrofit Tee for Hot Tap Applications

[+] Author Affiliations
Neil Woodward, Mike Armstrong

Isotek Oil & Gas Ltd., Leeds, England, UK

Kjell Edvard Apeland, Jan Olav Berge

Statoil ASA, Stavanger, Norway

Richard Verley

Statoil ASA, Trondheim, Norway

Paper No. OMAE2013-10765, pp. V003T03A027; 9 pages
  • ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering
  • Volume 3: Materials Technology; Ocean Space Utilization
  • Nantes, France, June 9–14, 2013
  • Conference Sponsors: Ocean, Offshore and Arctic Engineering Division
  • ISBN: 978-0-7918-5535-5
  • Copyright © 2013 by ASME


Over the last 10 years Statoil has developed subsea remote hot tap technology. The first use of the remote hot tap technology was the Tampen Link hot tap in 2008. The hot tap cutting operation itself was performed without the use of divers; however, the preparatory works including hyperbaric welding of the hot tap tee was performed with saturation divers. The world’s deepest hot tap operations on a pressurized pipeline were performed on the Ormen Lange field in the Norwegian Sea in August 2009. Two Hot Taps were conducted in a water depth of 860 meters on pre-installed tees. The development of the Pipeline Repair System Remote Hot Tap equipment is the result of targeted research and development effort and extensive qualification work over many years. The Retrofit Tee remote installation, welding and cutting equipment has now been employed as part of a production installation: the Åsgard Subsea Compression project to extend the Åsgard gas-field lifetime.

This paper describes the dry hyperbaric GMA weld procedure development and qualification performed in the laboratory, using the Corrosion Resistant Alloy consumable filler material Alloy 59, for the Remote Hot Tapping application using the Retrofit Tee. Specific attention was paid to areas of concern prior to performing the formal Weld Procedure Qualification work, particularly with regard to the effects of moisture and temperature upon the resultant weld quality. Weld procedures developed in the laboratory were successfully tested subsea in representative environments using the Remote Tee Welding Tool (RTWT) equipment in the Sognefjord, Norway, with offshore tests performed at 265 and 350msw in 2011. Further tests were performed in 2012 at 265msw and in the Retrofit Tee itself at 316msw in the Nedstrandfjord.

The hyperbaric GMA weld procedures have now been applied for the production application for the Åsgard Subsea Compression project, with the installation of a Retrofit Tee, associated valve module and gooseneck spool to enable a cost-effective modification to the existing pipeline network without interfering with ongoing production. The Retrofit Tee will be connected with a Subsea Compressor station to extend the gas-field lifetime.

This milestone represents the world’s first application of diverless dry hyperbaric GMA welding for a subsea production application.

Copyright © 2013 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In