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May 2005
(Houston,
TX) ABS’ release
today at OTC of its guidelines for the use of composite
materials on offshore structures is expected to facilitate
industry consideration of alternatives to costly
steel in the development of mooring systems and
risers, says Ernesto Valenzuela, Offshore Technology
Development Manager, ABS.
“It is no longer a question of if but when
composite materials will take their first starring
role in production from a deepwater hydrocarbon reservoir,” said
Valenzuela. “We have brought a comprehensive
set of criteria to operators wanting to apply fiber
reinforced plastics (FRPs) to their projects.”
Valenzuela explains that the ABS Guide for Certification
of FRP Hydrocarbon Production Piping Systems provides
technical guidance and design procedures for using
composites or FRPs on the topsides of offshore facilities. |
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As projects become more complex and move into deeper waters,
the topsides become heavier, the steel mooring systems and
risers become longer and heavier, thus presenting serious
challenges to project economics, says Valenzuela.
“These challenges have spurred research into substitute
materials that would do the job of steel, but at much lighter
weights. Once thought of as an exotic material, composites
and FRPs are gaining acceptance among operators,” said
Valenzuela.
ABS plans to unveil its composite guidance in three stages:
first, release of criteria for FRP in topside applications;
secondly, criteria for carbon-fiber composite riser piping
and joint application and; thirdly, criteria for composites
in cryogenic piping applications.
The move to synthetic mooring lines during the past decade
has been key in making some recent deepwater projects possible
and the offshore industry’s first step away from steel
and into alternate materials.
The use of composites, specifically carbon-fiber materials
replacing steel in production and drilling risers, and in
the tendons of tension-leg platforms (TLPs), is the next
step.
“Anticipating this need, ABS’ guide will help
industry. It applies practical experience to topside design
while we continue research and development to better understand
the nature of composite materials in more technically demanding
applications,” said Valenzuela.
The ABS issued Guide for Certification of FRP Hydrocarbon
Production Piping Systems is the first publication
of its kind from a classification society and is expected
to become the primary source of composite guidance available
to the offshore industry. Along with its class criteria,
ABS references criteria available from other organizations
such as the American Society for Testing and Materials
(ASTM) and the United States Coast Guard (USCG).
Advantages of carbon-fiber composites over the basic production
material of steel includes: higher strength-to-weight ratios,
superior fatigue performance and corrosion resistance and
better thermal insulation. Another advantage is a high structural
damping characteristic that makes composite risers (or tendons)
immune to vortex-induced vibration, a cause of severe fatigue
damage to steel structures.
Although weight is only one component in the complex considerations
that make up an offshore production solution, weight reduction
is among the most attractive benefits of composites.
“With less buoyancy expended on mooring systems or
risers, loads can be increased; more riser joints can be
stored on the rig and fitted through a smaller rotary table;
or a rig could carry extra casing, mud or chemicals,” said
Valenzuela.
The ABS guide addressing the use of composites for risers
is nearing completion. ABS researchers note that the vertical
orientation of the piping from the seafloor to the floating
structure requires detailed analysis of the longitudinal
and transverse strength of the piping to verify that it can
withstand the pressures.
With regard to its work with cryogenic piping, ABS sees
composites having very attractive thermal properties which
can make them ideal candidates for cryogenic piping. With
that, ABS anticipates heightened interest for composite applications
on liquefied natural gas (LNG) systems.
Founded in 1862, ABS is a leading international classification
society devoted to promoting the security of life, property
and the marine environment through the development and verification
of standards for the design, construction and operational
maintenance of marine-related facilities.
Editor’s Note: The
ABS Guide
for Certification of FRP Hydrocarbon Production Piping
Systems (Publication #137) is available for free download
from the ABS website in the RULES AND GUIDES section at: http://www.eagle.org/rules/downloads.html
For more information, contact:
Susan Gonzalez,
ABS
1-281-877-5853
or sgonzalez@eagle.org
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