Full Content is available to subscribers

Subscribe/Learn More  >

Wellhead Fatigue Analysis Method: A New Boundary Condition Modelling of Lateral Cement Support in Local Wellhead Models

[+] Author Affiliations
Lorents Reinås

University of Stavanger/Statoil ASA, Stavanger, Norway

Morten Sæther

Statoil ASA, Oslo, Norway

Johan Svensson

Validus Engineering AB, Staffanstorp, Sweden

Paper No. OMAE2012-83049, pp. 47-57; 11 pages
  • ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering
  • Volume 1: Offshore Technology
  • Rio de Janeiro, Brazil, July 1–6, 2012
  • Conference Sponsors: Ocean, Offshore and Arctic Engineering Division
  • ISBN: 978-0-7918-4488-5
  • Copyright © 2012 by ASME


Subsea wells are dynamically loaded during all drilling operations involving a drilling riser system which will cause fatigue loading of the subsea wellhead system and the upper structural components of a well. Estimation of loads and load resistance enables analysts to predict expected service life based on analytical models of well and riser systems. Analytical wellhead models may be a simplified representation of the reality but should still capture the essential physical behavior of the well. Ensuring sound boundary conditions for the analytical model is important and subject to debate amongst analysts. This paper addresses the importance of the well cement as a lateral supporting boundary condition of the wellhead and surface casing in local modelling of a subsea wellhead system. A modified boundary condition approach is suggested that differs from the previously published way of modelling cement in a wellhead fatigue context. This modified boundary condition is applied both to a 2D FEM wellhead model and to a more complex 3D FEM wellhead model. Analysis results with the new boundary condition and the previously suggested boundary condition are compared to understand the effect this modified cement boundary condition has on the analytical results. The effective level of cement is varied to investigate the sensitivity of cement boundary condition modelling. Results indicate less conservative analytical results for the modified boundary condition both for 2D and 3D modelling. The modified cement boundary condition suggested herein is believed to be relevant for deepwater and high latitude subsea basins as it takes into account the hindered strength development of oil well cement cured close to seabed under the influence of low seawater temperatures. We advocate that installation of BOP before cement has properly cured will improve fatigue life of surface casing weld.

Copyright © 2012 by ASME



Interactive Graphics


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

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