Evaluating Pipeline Risk Due to Strudel Scour

Strudel scours form during the spring river breakup when the river overfloods the nearshore landfast ice and drains through holes in the ice sheet, eroding circular or linear depressions in the seabed. When these depressions form over pipelines, damage can occur due to spanning. A probabilistic approach is described for the evaluation of risk posed to trenched pipelines by strudel scours. Strudel scour survey data related to the Northstar and Liberty Field developments has been reviewed to develop statistical representations of depth, diameter and formation density. A simple analytical method was developed to allow pipeline behavior to be predicted when spanning a strudel scour. The rate at which strudel scours form over a hypothetical pipeline was calculated using the probable length of pipeline exposed to strudel scour, formation rate and mean size. The distribution of pipeline span lengths, given formation of a strudel scour over the pipeline, was calculated using the updated distribution of strudel scour diameter and depth, with appropriate assumptions regarding strudel scour geometry (cross-sectional shape). Annual failure rates for varying cover depths were calculated using the proportion of pipeline spans exceeding the critical length, the annual formation rate over the pipeline and the target reliability level. Sensitivity to soil type, scour cross-sectional shape, scour depth and infill were investigated.

• Record URL:
  • http://www.poac.com/Papers/POAC09_72-152.zip
• Summary URL:
  • http://www.poac.com/PapersOnline.html
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/03766756
• Supplemental Notes:
  • Abstract reprinted with permission of the International Conference on Port and Ocean Engineering Under Arctic Conditions (POAC).
• Corporate Authors:

  Port and Ocean Engineering under Arctic Conditions (POAC)

  ,    
• Authors:
  • King, Tony
  • Phillips, Ryan
  • Barrett, John
• Conference:
  • 20th International Conference on Port and Ocean Engineering under Arctic Conditions (POAC'09)
  • Location: Luleå , Sweden
  • Date: 2009-6-9 to 2009-6-12
• Publication Date: 2009

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Maps; References; Tables;
• Pagination: pp 608-617
• Monograph Title: POAC '09: Proceedings of the 20th International Conference on Port and Ocean Engineering under Arctic Conditions
• Serial:
  • Proceedings of the International Conference on Port and Ocean Engineering Under Arctic Conditions
  • Publisher: Port and Ocean Engineering under Arctic Conditions (POAC)
  • ISSN: 0376-6756
  • EISSN: 2077-7841
  • Serial URL: http://www.poac.com/PapersOnline.html

Subject/Index Terms

• TRT Terms: Depth; Ice concentration; Ocean bottom; Risk analysis; Scour; Sea ice; Underwater pipelines
• Subject Areas: Environment; Marine Transportation; Pipelines; I15: Environment;

Filing Info

• Accession Number: 01554853
• Record Type: Publication
• Report/Paper Numbers: POAC09-74
• Files: TRIS
• Created Date: Feb 26 2015 9:54AM