Since mid-1980’s, guidelines permit the design of rigid subsea pipelines allowing significant lateral displacements under extreme environmental conditions. Such a design criterion might bring issues not foreseen in the original design when future assets are to be installed in close proximity — for example pipeline crossings, hot-tap tie-ins or parallel lines using the same corridor. Although not limited to any particular region of the globe, this issue has been showing increasing relevance in the Australian North West Shelf over the last few years. The combination of environmental and geotechnical conditions in that region has led to significant advances in engineering design techniques, and to audacious projects which made viable a number of important subsea pipelines which have been designed to be dynamically stable. As this oil and gas province matures, the installed infrastructure in the region forms part of an increasingly complex subsea network.

The design of new subsea assets close to, crossing, or tying into these dynamically stable pipelines require the reassessment of the existing infrastructure for potential clashing conditions. This paper discusses the techniques and integrity criteria available for reassessing dynamically stable pipelines whose originally expected displacements may be incompatible with new required infrastructure. Although the criteria for confirming the structural integrity is, and has to be, grounded on established design codes, the assessment often require advanced engineering and state-of-the-art analysis techniques.

This content is only available via PDF.
You do not currently have access to this content.