The J-Lay method is used for pipelines with diameter from 10-50'' in deep and ultra deep waters. A vessel with a vertical J-lay tower is required. Pieces of pipe are welded together in the tower and lowered vertically in to the seabed (Fig. 2)

Vessel Name Tesioner (with clamp) Diameters OD Depth [m] DP
Seven Borealis 940 t 2" - 36" 3000 m  YES
Aegir 800t (2000 t) 2" - 32" 3500 m YES
Saipem 7000 750t (2000 t) 4" - 32"   YES
Deep Blue 770 t 4" - 28"   YES
Sapura 3000 360 t 2" - 20" 2750 m YES
         
         
         


For example the Pipelaying vessel Aeger can install pipeline up to 32” OD and has a maximum top tension 2,000 mT.

Advandages

  • Installation rigid and heavy pipelines in deepwater. 
  • Installation of fatigue sensitive pipes such as risers.
  • Easy installation of PLETs, ILTPs though the moonpool.
  • Larger weather window
  • Fast and relatively safe abandonment and recovery.

Disadvantages

  • Low pipelaying rates due to single welding, NTD, coating station;
  • Not suitable for shallow pipelaying.