Tensioning system aids deepwater pipelay and module installations
Gusto MSC has developed a new J-lay system that combines the company’s proven mechanical positive engagement technique with a system known as “Knobbeltouw.” The latter, made from synthetic lightweight Dyneema cable, allows the same tensioning equipment to be deployed for pipe lay and abandonment and recovery operations, saving the need for an additional A&R winch.
The J-lay system is designed to occupy a minimum-possible footprint, with a limited number of moving parts, in turn reducing maintenance costs. It is suitable for installation on most pipe lay vessels, either at the stern or amidships. It can accommodate a range of pipe diameters, and should be suited to short infield lines associated with hook-up of FPSOs, Spars and TLPs.
The system employs a hand-over principle to lower the pipes to the seabed, either quadruple, triple joint or double joint. According to Gusto MSC, this makes it suitable also for deepwater installation of templates, subsea manifolds and distribution units. The equipment can be installed either on a newbuild vessel or as a retrofit package. Its current design includes a tension system with a holding capacity of 550 metric tons, allowing for a pipe lay rate of 2,500 - 4,000 m/day. Pipe diameters handled would range from 4-32-in. for rigid lines, to 4-16in. for flexibles, with J-lay angles from 60-90deg. The 750 metric ton J-lay system would occupy a deck space of 87 x 10 m, with a moonpool dimensioned at 6 x 12 m.
The Knobbeltouw is well suited for deepwater applications, GustoMSC adds, as the coupling of strands allows deployment of very long lines. Its normal subsea installation capacity of 500 metric tons would be suited to operations in a water depth of 3,000 m. However, this could theoretically be stretched to 6,000 m for a 450 t load, following further modularization of the package.•
