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Speed of pipelay per day
3

Speed of pipelay per day

Speed of pipelay per day

(OP)
Hi,

I've received information on a pipelay vessel estimated to lay 3.5km 42" pipe per day on DP. In the Nordstream project, I believe the vessel lay speed could go up to 4km.

Someone commented that a rate of 4km per day is too fast. Is there a higher likelihood of wet buckle the faster the laying? On the other hand, is there such a thing as minimum km per day?

Appreciate your response.

RE: Speed of pipelay per day

The Horn Mountain 10in pipeline installed by Allseas using S-lay achieved a maximum lay rate of 9 km / day.

RE: Speed of pipelay per day

The layrate drops as the pipeline diameter increases.
Other modifiers are higher wall thickness, concrete coatings/insulation, using CRA material or piggy backed lines.
The vessel lay capability is more about the welding and the fitting up of the spools rather than buckling I believe.

I have heard of 3km/day for 18" and 2km/day for 30", this was for a deep water project using S-Lay.

RE: Speed of pipelay per day

(OP)
Grateful for your responses.

In this case I am looking at the Castorone with the capability for either J or S at depths of <300m, who will be laying 42" S-lay. This vessel is certainly capable of many things.

I was informed of multiple dents due to lay issues and whilst I do not know the details, could the increased layrate raise the risk?

Is the maximum layrate determined during buckling designs? I suppose if it wasn't then it is not a concern, yes? Is the J-lay process faster than the S-lay, assuming all else equal?

RE: Speed of pipelay per day

Generally the J-lay method of installation is slower than the S-lay method. But depending on the height of the tower, upwards of 4-6 prefabricated multi-joint section can be welded in the tower considerable closing the gap of lay rates between the two.

RE: Speed of pipelay per day

Lay rate is greatly controlled by 3 parameters,
pipe diameter, ie. length of weld/pass,
wall thickness, ie, number of weld passes,
and length of barge, ie. how many weld layers you can make simultaneously vs number of weld stations that you can fit on it, assuming one pass per weld station.
(With a J lay, the number of weld stations in the tower).
Obviously a tiny barge with only 1 weld station is going to have a very slow rate of progress as only a small number of passes can be made at the same time.

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