The vertical riser is used to provide the vertical flow path for the fluid from the seabed. It should be multi-layered flexible pipe of unbounded construction, suitable for dynamic applications.
The riser should consist of at least the following four layers:
- An inner layer of interlocked steel carcass to provide structural strength against pipe collapse.
- A fluid-containing liner for making the pipe leakproof.
- An armor layer to sustain axial loads.
- An external plastic sheath to hold the underlying armors in place and provide resistance to corrosion and abrasion.
Pipe Construction and End Fittings
- Details of the non-bonded pipe construction and end fittings can be found in API RP 17B, Section 3.
- The flexible pipe should be fitted at either end with the following:
- End fittings
- Bending stiffeners
- The bottom end should terminate at the riser base through a collet connector and a ball valve.
- The upper end should be mated to the subsea swivel attached to the subsurface buoy.