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Pipeline Walking MitigationNew pipeline restraint approach takes a big step forward!

Subcon > News > Pipeline Walking Mitigation – new pipeline restraint approach takes a big step forward!


Pipeline Walking, Rogue Buckling and Pipeline End Expansion remain a key challenge for operators in high temperature and pressure fields, especially in deep water.  Pipeline Clamping Mattresses provide a cost competitive and elegantly robust solution for preventing pipeline walking with some key implementation advantages over traditional methods.

The system was developed by Shell and Subcon in 2015 and has since been successfully implemented on both Malampaya pipelines.  The system applies 100% of the additional ballast weight onto pipelines mobilising the pipeline to soil interface friction to effectively and efficiently control pipeline walking and end expansion.

The method was recently presented by our founder Matthew Allen at AOG2020 in Perth.  If you missed it and would like to view Matthew’s presentation you can do so here.

New Projects

Subcon have recently been awarded two walking mitigation contracts – one for West Africa and one for Asia Pacific and expect more later in 2020 as the technology gains industry acceptance and popularity as an economical, post installed solution.

The client highlighted that “Subcon delivered an excellent product for us on an accelerated schedule.  The fabrication and installation went very smoothly and is a credit to the Subcon team and their elegant design of the PCM.”

Centrifuge Testing Update

In addition a number of operators have participated in a joint research project coordinated by subcon and conducted at the University of Western Australia’s Centre for Offshore Foundations (COFS) to investigate PCM performance in a range of soil types.

Shell Chair at COFS, Dr Phil Watson said, “The results have validated the design methodology and the superior performance of the system.  The tests run in our large centrifuge facility were very compelling!”.  COFS have two centrifuges supported by an extensive team of operators, analysts and fitters who built the robotic test rig and instrumentation in house.  You can learn more about the testing on our Walking Mitigationpage.

The large centrifuge was used to replicate soil consolidation and PCM performance in three regions, including Gulf of Mexico and Australia.

Subcon’s Business Development Manager, Jack Francis has led the team delivering the project awards and research.  He said, “an exciting outcome of our partnerships with leading design houses has shown the PCM can also be used to deliver significant reductions in the size and cost of expansion spools, PLETs. Designers can specify PCMs to reliably control pipeline end expansion and in doing so, deliver real development cost savings for their clients”.

New Applications

Reducing the size of PLETS and Expansion Spools by controlling end expansion delivers material reductions in material costs as well as knock-on costs like handling spreaders, onshore logistics, vessel and subsea installation costs.

PCMs deliver radical operational and installation advantages when compared with concrete mattresses, rock berms, suction piles, large expansion spools and PLETs.  To learn more about the economic and operational benefits of PCMs please visit Walking Mitigation or send our team an enquiry.  Our engineers will be happy to provide advice specific to your application.

The PCM technology is patented by Shell who has made the technology available to all contractors and operators through an exclusive license agreement with Subcon.