What is flexible pipe?
A flexible pipe is made up of several
different layers. The main components
are leakproof thermoplastic barriers
and corrosion-resistant steel wires.
The helically wound steel wires give
the structure its high-pressure resistance
and excellent bending characteristics,
thus providing flexibility and
superior dynamic behaviour. This
modular construction, where the layers
are independent but designed to
interact with one another, means that
each layer can be made fit-for-purpose
and independently adjusted to best
meet a specific field development
requirement.
Main Characteristics
FLEXIBILITY
Flexibility is the distinctive property of
a flexible pipe. A typical 8'' internal
diameter (ID) flexible pipe can safely
be bent to a radius of 2m or less. This
is the reason why flexible dynamic
risers have been the enabling technology
for floating production systems.
This flexibility is also important for
flowlines laid on uneven seabed conditions.
Flexibility makes it possible to
spool the pipe on a reel or in a carousel
for efficient and quick transportation
and installation.
INSTALLABILITY
Because the flexible pipe comes in a continuous length, laying speed commonly averages 500m per hour. Separate sections are connected on deck during installation, eliminating the need for any intermediate riser base structure or subsea connections. This elimination of interfaces reduces risk in operation. In November 1971, the first Technip flexible pipe was installed in Congo. It took 1.5 hour to lay the 650m flowline, including connections.
MODULARITY
The independent layers of a flexible structure enable it to be tailored to the precise needs of a specific deve-lopment. Simple flexible pipes for medium pressure water transport comprise only four layers. The most complex flexible pipes may have up to 19 layers. Beyond the basic fluid barriers and stress-resistant wires, additional layers can be included to prevent wear between steel layers (in dynamic appli-cations) or to provide improved thermal insulation (“standard” flexible pipe already has a much better insula-tion coefficient than that of steel pipe). Besides including new thermoplastic or steel layers within the product, it is also possible to assemble plastic hoses, electrical cables or optical fibers around a flexible pipe to produce an Integrated Service Umbilical (ISU®), or include active heating for flow assu-rance in deepwater to produce an Integrated Production Bundle* (IPB). In 2001/2002, Technip participated in the DEMO 2000 JIP, demonstrating its ability to supply heat traced flexible, including gas lift tubes and tempera-ture monitoring optical fibers within the same line (Integrated Production Bundle). Heat tracing and monitoring allow temperatures to be perfectly tuned within the core production flexible in order to meet flowing or
cool down requirements. This type of flexible pipe provides an “all-in-one” solution for deepwater applications. It has been used several times in West of Africa deepwater fields and will soon be installed offshore Brazil.
CORROSION RESISTANCE
Since the steel wires are not in direct contact with the conveyed fluid, they do not require the same corrosion resistance as steel pipe. This means that our design experience and knowledge of gas diffusion through thermoplastic materials enable us to use carbon steel where the equivalent rigid pipe appli-cation would require much more expensive corrosion-resistant alloys
Source: http://www.technip.com/sites/default/files/technip/fields/publications/attachments/flexible_pipe_march_2014_web_0.pdf
Source: http://www.technip.com/sites/default/files/technip/fields/publications/attachments/flexible_pipe_march_2014_web_0.pdf
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