Pipelaying visualised

October 11, 1999, 10:00 CEST

A new computer tool which permits a pipeline to be "seen" three-dimensionally during offshore laying could cut accidents and save both time and resources.

This solution took Statoil just under three months and NOK 350,000 to develop in cooperation with Geodata, and it was deployed for the first time this summer in the Vestprosess project along the west Norwegian coast.

The tool proved particularly useful in laying pipe along the very difficult bed of the Fens Fjord into the group's Mongstad complex near Bergen.

"We've found this an invaluable source of assistance," says Ove Sembsmoen, project manager for Vestprosess pipelaying. "I don't think we could have completed the job with such good results without its help."

An accident while laying Troll Oil Pipeline II through the same fjord a couple of months earlier prompted the development of the visualisation tool, reports Øivind Nilsen.

He is manager for the metocean, survey and geotechnics sector in the pipeline and subsea production systems unit.

While pipelayers previously had to rely on two-dimensional paper charts, they can now follow vessel and pipeline movements in the terrain from second to second through a 3D model on a computer monitor.

The GPS global positioning system installed on the vessel sends continuous signals about these movements to the computer, while the pipe being laid is simulated mathematically by the 3D model and also updated continuously.

Standard software has been applied to construct the tool, which can be used on any vessel involved in a pipelaying operation.

"The aim is to make pipelaying more secure over rough seabed terrain," explains Mr Nilsen. "Our experience so far has been very good, and this tool will be highly relevant for all future pipeline projects."

He reports that it can also save a great deal of work for such projects in the planning phase by providing a better basis for choosing pipeline routes. That in turn cuts the need for vessels during laying.