Skip to content
Search
Type
Lecture

Offshore pipeline integrity ensured with Engineering Critical Assessment

Event organised by Offshore Engineering Society

Date
01 March 2023
Time

This event has now ended

You can catch-up on details or any broadcast and downloads here.

Overview

The integrity of offshore pipelines is ensured with fatigue and fracture calculations. Taken holistically with material testing and inspection, these calculations are called Engineering Critical Assessment (ECA).

ECA is a hugely challenging multi-disciplinary subject that calls for the highest level of analytical and research skills in applying fracture mechanics to such diverse technologies as pipeline materials, welding, installation and operational design and engineering.

ECA is placed, therefore, at the intersection of material, stress, and inspection technologies and ECA practitioners work on a close inter-discipline basis with experts in these fields to ensure the predicted loads on a pipeline system can be withstood by the parent pipe and weld metal, accounting for inherent post-weld defects, for the full design life.

In this talk Daowu Zhou and Graeme Roberts will outline ECA procedures for reeled pipelines, where bending strain in the steel can reach 2%. A general overview of ECA in the reeling, installation, operating and end-of-life phases will be presented as will a recent validation programme of ECA for reeled pipe.

Finally, the value and future of ECA will be briefly outlined, as pipeline design transitions from conventional to carbon capture and hydrogen transportation.

Speakers

Dr Daowu Zhou

Dr Daowu Zhou

Subsea7

engineering manager and eca team lead

Read more

Dr Daowu Zhou

Dr Daowu Zhou received both a Bachelor and Master of Engineering degree in aeronautics from Northwestern Polytechnical University from China. Daowu obtained his PhD from University of Cambridge on solid mechanics in 2005. He subsequently worked at Imperial College London as a post-doctoral research associate and characterised composite sandwich material joint failure under explosive loading.

In 2007, Daowu joined TWI Ltd at Cambridge and carried out industry research on structural integrity. His research topics included: welding residual stress modelling and measurement, welding induced distortion modelling, TWI JIP on strain-based pipeline ECA, development of an algorithm and subroutine for calculating J-integral under dynamic loading with inertia effect, and FE-based fatigue assessment.

Daowu’s research on constraint-based fracture mechanics was implemented in the R6 code in nuclear industry and forms the foundation for subsequent constraint-based ECA procedure in BS7910 2019. He also carried out explorative research on SENT testing which paved the way for TWI’s JIP on industry standardisation of SENT testing and subsequent BS8571.

Daowu joined DNV in 2010 and principally researched X80 offshore pipeline girth weld integrity under large deformation and DNV’s JIP on treatment of residual stress in ECA of pipeline girth weld under high plastic deformation. He moved to Subsea7 a year after and has been working in Subsea7 for 11 years.

Graeme Roberts

Graeme Roberts

Subsea7

engineering specialist

Read more

Graeme Roberts

Graeme Roberts got his Master of Engineering degree from Portsmouth Polytechnic in 1989 and has worked in the offshore sector ever since. He has lived and worked in the UK, Norway, the Netherlands, UAE, and Canada and has carried out project analysis and design work for jackets, topsides, FPSOs, and subsea pipelines, and for the iconic Burj Al Arab hotel (which is ever so slightly offshore).

Graeme has been involved with pipeline system project ECAs and associated R&D programmes since 2010. To help ECA practitioners in Subsea7, Graeme wrote the FrickFrack Excel functions that can automate complete ECA sequences. FrickFrack runs in either the forwards or reverse sense of defect growth and is validated against TWI’s CrackWISE®.