Seabed mobility, sand waves migration & pipeline burial criteria

Seabed dynamics plays an important role in selecting offshore pipeline site and optimizing pipeline route. It is one of the critical design parameters in the design of a pipeline through a morphologically dynamic area such as migrating sand waves.

We have extensive knowledge and experience in predicting future extremely low seabed level in a morphologically dynamic area, which is required to determine the burial depth of a pipeline.

Both short term and long term coast evolution will be assessed to quantify the expected lowest seabed level along the pipeline route in the landfall area during the pipeline lifetime.

Approach

The long term morphological changes originate from long term variations in the morphological system (e.g. river input), gradient in the longshore sediment transport and long term variations in the hydrodynamic conditions. The short-term morphological changes originate from beach profile variations due to cross-shore sediment transport as a result of seasonal and yearly variations in the wave and current conditions.

Bed forms (e.g. sand waves) may be generated, develop and migrate on an erodible seabed. The development of bed forms may result in seabed changes. The dynamics of possible bed forms will be assessed based on the available bathymetry data and the metocean data. The stability and possible migration behaviour of sand waves will be evaluated.

Numerical modelling can be applied to compute the longshore and cross-shore sediment transport rates and the resulting coastline evolution and cross-shore profile evolution.

Publications

Selected publications by our staff:

  • Chen, Z. et al, Morphology and Pipeline Design Through a Dynamic Landfall Area, The Black Sea Pipeline, Proc. Of Offshore Mechanics and Arctic Engineering Conference, Oslo, 2002.
  • Chen Z. et al An Integrated Approach To Pipeline Design Through Sandwave Fields: Dongfang Pipeline, OMAE conference, Brazil, 2001.
  • Chen, Z et al Probabilistic Design of Burial Depth of Offshore Pipelines and Cables, Proc. Of Offshore Mechanics and Arctic Engineering Conference, Lisbon, 1998
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