Hyperbaric GMA Welding for Contingency Repair using a Fillet Welded Sleeve at 1,000m Water Depth

摘要

Hyperbaric GMA welding has recently been qualified for a new diverless subsea pipeline repair method using a fillet welded sleeve for pipelines in the water depth range 180 to 370m. Parameter development work and the resultant mechanical properties have been reported for X65 and X70 pipeline grades welded with a specially developed 1.0mm metal-cored wire with a sleeve made to X65 specification. This paper describes the deepwater process heritage and focuses upon the welding design and work carried out for qualification at 1,000m for the Ormen Lange pipeline, and includes descriptions of the parameter development challenges for orbital welding, the electrical and process stability and the resultant mechanical property performance at this water depth.