Offshore Flexible Pipe

In the advanced development of technology, oil and gas industry explores further from shore and deeper to the basin. It is inevitable that the deeper it goes, more pressure it receives. This become a concern in planning a safe pipeline system. For that reason, a new kind of offshore pipeline is invented, the flexible pipe.

A flexible pipe is made up of several different layers. The main components are leak-proof thermoplastic barrier and corrosion-resistant steel wires. The helically steel wires give the structure its high pressure-resistant and excellent bending characteristic, so it provides flexibility.

 
 

Typical Flexible Pipeline

Source : http://vertassets.blob.core.windows.net/image/f8134447/f8134447-d0df-11d4-8c88-009027de0829/o2.gif

Main Components

Figure below identifies the main components of flexible pipe cross section:

Component of Flexible Pipeline

Source : https://nonerieska.wordpress.com/2013/01/31/offshore-flexible-pipe/

1.      Interlocked stainless steel carcass
2.      Internal pressure sheath, made from nylon, poly vinylidene flouride (PVDF) and high density polyethylene (HDPE)
3.      Zeta spiral (pressure armour), made from rolled carbon steel
4.      Tensile armour (double cross wound armours), made from flat rectangular wires
5.      Outer thermoplastic sheath, made from non-metallic materials

Main Characteristics

•  Flexible. Makes it possible to spool the pipe on a reel or in a carousel for efficient and quick transportation and installation.

• Easy to install. Since the flexible pipe is in continuous form, laying speed will be much faster than laying ordinary rigid carbon steel pipeline.
• Modularity. The independent layers of a flexible structure enable it to be tailored to the precise needs of a specific development.
• Corrosion resistant. Since the steel wires are not in direct contact with the conveyed fluid, they do not require the same corrosion resistance as steel pipe.
• High pressure resistant. Flexible pipes resist all fluid pressures encountered in the most complex subsea application. Besides, the modularity of the flexible pipe manufacturing process enables to adjust pipe thickness, shape, and number of steel wire layers to satisfy a specific requirement.

The image above shows the physical form of flexible pipe.

 Forming Flexible Pipeline

Source :
http://www.technip.com/sites/default/files/technip/publications/attachments/Flexible_pipe_Web.pdf

References:

http://www.technip.com/sites/default/files/technip/publications/attachments/Flexible_pipe_Web.pdf

http://www.outokumpu.com/en/CustomerIndustries/Project-and-Process-Industries/Oil-And-Gas/Flexible-Pipe/Pages/Flexible-Pipe.aspx

Chen, Minghao. Fatigue Analysis of Flexible Pipes Using Alternative Element Types and Bend Stiffener Data. Norwegian University of Science and Technology (NTNU). Norway. 2011.

https://nonerieska.wordpress.com/2013/01/31/offshore-flexible-pipe/

Dega Damara Aditramulyadi

Student ID : 15512046

Course      : KL4220 Subsea Pipeline

Lecturer   : Prof. Ir. Ricky Lukman Tawekal, MSE, Ph. D.

                  Eko Charnius Ilman, ST, MT

Ocean Engineering Program, Institut Teknologi Bandung

http://www.ocean.itb.ac.id/en/