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Improving Global Quality of Life
Through Optimum Use and Innovation of Welding and Joining Technologies
industry have resulted in the need for operators to provide an increasing number of branch connections for
new suppliers and new customers, many of which are made by hot tapping. Deregulation in some countries
has also made the industry more competitive than ever, so in-service repairs and modifications are more
attractive than ever.
9.4.2
Technology trends
There is a unique dichotomy that tempers the technology development of the oil and gas pipeline industry.
One is the idea that new technology is the means to reduced cost and increased quality. The other is the
idea that the risk lies in the unknown and untested. This divergence in thought is present in every industry.
As such, the pipeline industry tends to be driven as much by perception and opinion as discovery and
scientific facts.
In the mid 1980s, several organisations (PRCI, US-DOT, TWI, EWI, etc.) developed reports predicting where
the pipeline industry was headed. The common thread of these reports was that they were all accurate at
the time of their release yet none were completely accurate in their predictions. Unforeseeable changes
and technology advancements altered where industry progressed. The thought process and available
information at the time of their authorship, suggested that solid state welding technologies were going to
be the dominant practice for pipeline fabrications.
The unknown of time was that weld inspection was going to be critically tied to the fitness-for-service (FFS)
and engineering critical assessments (ECA). FFS and ECA tended to drive down the acceptable flaw sizes for
welded pipelines. The reality became apparent that the fundamental limit of the NDE equipment became
the underpinning limitation that controlled a pipelines life prediction and safety factor. Thus, work was
underway to improve and optimise the accuracy and limits of NDE technologies. Field NDE companies began
to adopt techniques (under the direction of the pipeline owner companies) like automated ultrasonic testing
(
AUT). This technology had historically been utilised in the nuclear industry and enabled a tremendous leap
in pipeline fabrication understanding and life assessments.
Current pipelines construction methods for all but major pipelines projects have not changed much in the
past 40 years or so. Many medium to small diameter pipeline are still welded using shielded-metal arc
welding (SMAW) and cellulosic-coated electrodes, and inspected using radiography. There is a need to
develop or assist companies in implementing some of the emerging pipelines construction technologies for
medium to small diameter pipeline projects. For pipeline operations, there is a need to develop innovative
pipeline repair technologies. Fibre-reinforced composite repairs are becoming widely used as an alternative
to welded full-encirclement steel sleeves, although there are concerns about the long-term performance
of these systems. As pipelines become older, the need for repair will only increase as the result of the
deterioration of protective coating materials over time and the time-dependant nature of corrosion.
Major pipelines in the near future will certainly be constructed using mechanised welding equipment
and the completed welds will be inspected using automated ultrasonic testing (AUT) equipment. Future
development in pipeline technology include the use of even more productive welding processes that go
beyond the optimisation of the GMAW process (e.g. dual torch, tandem torch, dual tandem, etc.) and
further development of the AUT process (e.g. phased array transducers). These developments may include
the use of hybrid laser/GMAW for all or a portion of the weld or the use of ‘single shot’ welding processes
such as friction stir welding. Control of weld quality may be accomplished in the future by advanced process
control methods instead of non-destructive examination of completed welds.
Nowone seesmanynewweldingautomation techniques beingdeployed to fabricatepipelines. Unfortunately,
the predictions of a world where pipeline welds take a few seconds to produce using technologies like flash
butt welding, dc butt welding or magnetically impelled arc butt welding has not yet come to pass. New solid-
