0

Full Content is available to subscribers

Subscribe/Learn More  >

Free-Span Flowlines Resistance to In-Service Fatigue Loading

[+] Author Affiliations
Francesco Iob, Elisabetta Mecozzi, Luigi Di Vito

Centro Sviluppo Materiali S.p.A., Roma, Italy

Philippe Darcis

Tenaris Dalmine, Bergamo, Italy

Israel Marines-Garcia, Hector M. Quintanilla-Carmona

Tenaris Tamsa, Veracruz, Mexico

Paper No. OMAE2015-42034, pp. V05BT04A024; 9 pages
doi:10.1115/OMAE2015-42034
From:
  • ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering
  • Volume 5B: Pipeline and Riser Technology
  • St. John’s, Newfoundland, Canada, May 31–June 5, 2015
  • Conference Sponsors: Ocean, Offshore and Arctic Engineering Division
  • ISBN: 978-0-7918-5652-9
  • Copyright © 2015 by ASME

abstract

Offshore petroleum fields frequently pass over areas with uneven seafloor. In such cases the pipeline may have free spans due to depressions crossing and are subjected to complex loading spectra. A major source for dynamic stresses in free span pipelines is vortex induced vibrations (VIV) caused by steady current since wave induced velocities and accelerations will decay with increasing water depth.

The complex loading spectrum differs sensibly from the constant amplitude loading commonly adopted for qualification of the product (line pipe and its girth welds). Centro Sviluppo Materiali and Tenaris for some years are involved in the study of in-service variable amplitude fatigue loading of risers trough numerical calculations and comparison of the actual fatigue loading experienced by free span system with constant amplitude qualification typical loading. Two papers [1, 2] have been already presented in previous OMAE conferences. The present work reports a study dedicated to the free-span flow lines.

The flow line analyzed is composed by OD 273.05 mm × WT 25.4 mm pipe lying on the uneven seabed. In particular the attention is focused on the analysis of VIV and its effect on fatigue life of the line. The Ormen Lange field, located at 120 km northwest of the Mid-Norway, was selected as reference scenario for the study.

One of the most important factors influencing the pipeline response to the VIV is the free-span length. A sensitivity analysis about the influence of different parameters (free span length and fluid velocity) on system response and consequent fatigue damage has been performed.

A case study has been selected among the cases considered in the sensitivity analysis, to produce the loading spectra to be considered in a laboratory fatigue testing campaign on strip specimens.

The fatigue performance of these samples has been compared to analogous samples subjected to constant and variable amplitude loading available from previous works [1, 2] on riser systems (Steel catenary riser and Hybrid riser).

Copyright © 2015 by ASME
Topics: Fatigue

Figures

Tables

Interactive Graphics

Video

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

NOTE:
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