Pipeline Routing

Generally offshore pipeline and cable route selection is based on the following principles :

·         Pipeline and cable should be routed to to minimize overall route length (or in general to minimize overall pipeline or cable laying cost). To minimize costs of the project, the selected route shall be as short as possible (as far as possible, the selected route shall be straight line). Note that for a 16″ offshore pipeline, reduction of every km in pipeline route length reduces 1 M$ of the total project costs

·         Pipeline and cable should be routed in the proposed survey corridor

·         Pipeline and cable should be routed away from any sea floor obstructions, hazards, or depressions which may create massive free spans

·         Whenever practical the selected route should avoid anchorage areas, existing underwater objects such as sunken vessels and pilings, active faults, rock outcrops, and mud slide areas.

·         Presence of other pipelines, installations, and wellheads should be considered

·         Presence of regularly dredged areas and dumping grounds should be considered

·         Instabilities of the soil beneath the pipeline or cable should be considered in pipeline routing

·         Spanning analysis should be undertaken based on data from geotechnical survey to identify any locations where possible free spans will be longer than pipeline design span length

·         Pipeline and cable should be routed to minimize number of crossings

·         Whenever practical, areas with intensive fishing activities (regions with finishing grounds) should be avoided

·         For trenched pipelines and cables, the sediment along the selected route should have sufficient thickness

Reference :
API RP 1111
BSI 8010, Part 3, Offshore Pipelines
Guidance Nots on Geotechnical Investigations for Marine Pipelines, Society for Underwater Technology, 2004