Material and tech breakthroughs are helping to improve the safety of
offshore pipelines while reducing ongoing costs. In this feature, Offshore
Technology profiles five of the industry's most promising new pipeline innovations.
Although pipelines are the fastest and most efficient way to transport oil
and gas, a number of onshore pipeline leaks in the last few years have raised
reasonable environmental concerns about their vulnerability in the long-term.
In increasingly deep offshore operations, meanwhile, the stakes are even
higher as the operating environment is more challenging and a subsea leak is
far more difficult to contain.
With these risks in mind, new breakthroughs in technology and material
science are helping to bolster the safety, reliability and efficiency of
offshore pipelines. Here we round up five of the industry's most promising
recent pipeline innovations, from anti-corrosive coatings to adhesive repair
systems, that are boosting safety credentials while reducing the installation
and maintenance costs of operating in the harsh marine environment.
Hydrate-phobic liquid coating
One of the many technical challenges of establishing and maintaining
production in increasingly deep waters is the build-up of methane hydrates -
ice-like crystals that form when methane comes into contact with cold ocean
water. The dangers of methane hydrates were highlighted during the Deepwater
Horizon spill, when these crystals blocked the opening of the containment dome
that engineers had placed over the leak. Methane hydrates are also a risk for
subsea pipelines, as crystals can form on the inside of pipes, disrupting the
flow or even causing blockages.
New research carried out by a team at Massachusetts Institute of Technology
(MIT) is now offering an alternative to the current expensive and
energy-intensive hydrate mitigation techniques. The team developed a
hydrate-phobic liquid coating with similar surface energy properties to those
of the hydrate, and observed that application of the coating reduced hydrate
adhesion by a factor of four when compared to bare steel.
Although the research is still some way from becoming available to offshore
operators, the MIT team's research paper, published in Physical Chemistry
Chemical Physics, notes that the studies "provide a framework for the
development of hydrate-phobic surfaces, and could lead to passive enhancement
of flow assurance and prevention of blockages in deep-sea oil and gas
operations."
Magma Global's m-pipe: flexible subsea
riser
Launched at the Offshore Technology Conference (OTC) in Houston in 2012,
Magma Global's m-pipe carbon and polymer subsea riser is promising a new
solution to the problems operators are experiencing with steel and unbonded
flexible pipes.
The flexible riser material, which combines lightweight (one tenth the
weight in water of steel risers) with strong fatigue and corrosion resistance
and high strain tolerance, is being marketed as a way to unlock new riser
configurations to simplify deepwater, high-pressure and high-temperature subsea
production operations.
Delegates at OTC were impressed by the material's possibilities, with 2H
Offshore's principal director Steve Hatton commenting: "Its weight and
high resistance to fatigue and corrosion solve many of the problems that riser
designers are currently struggling to accommodate with current steel and
flexible solutions. I believe the new technology developed by Magma will reduce
risk and installed cost of riser systems - the time has finally come for the
use of this type of material in the offshore industry."
DNV's new deepwater pipeline concept
The offshore industry's movement into deeper waters has major cost
implications due to the complexity of transporting oil and gas back to the
shore, ushering in a greater use of expensive LNG plants and FPSO vessels. The
main challenge with deepwater pipelines is the thickness of the pipes, which is
necessary to withstand deepwater pressures but creates a weight that makes
installation and welding difficult.
Marine classification society and risk manager DNV's solution to this
problem is X-Stream, a new pipeline concept that controls the pressure
differential on the inside and outside of the pipe, allowing a significant
reduction in weight when compared to the current standard.
"By utilising an inverted High Pressure Protection System - i-HIPPS -
and inverted Double Block and Bleed valves - i-DBB - the system immediately and
effectively isolates the deep-water pipe if the pressure starts to fall," said
DNV global pipeline director Asle Venås on X-Stream's launch in January 2012.
"In this way, the internal pipeline pressure is maintained above a
critical level for any length of time." The company believes that, for a
gas pipeline in 2,500m of water, pipe wall thickness can be reduced by 25-30%.
Neptune: Dow's subsea insulation
system
Developed by Dow, the Neptune subsea flow assurance insulation coating is the
end-product of a multimillion dollar R&D project carried out over several
years. While Dow notes that competitive coatings often require up to seven
layers to protect pipelines with adequate thermal and corrosive protection,
Neptune needs only two - an anti-corrosion, fusion-bonded epoxy coating and an
insulation coating based on hybrid polyether thermoset material.
With these two layers, Dow claims that Neptune can provide temperature
performance from -40°C to 160°C during installation and use, at depths of up to
4,000m.
"Market knowledge, chemistry expertise and innovation capabilities of
Dow - combined with the application expertise of the coaters with whom we have
collaborated - have enabled us to deliver a flow assurance wet insulation
solution with the widest temperature range available on the market today,"
said Dow Oil & Gas general manager Larry Ryan. Neptune was made available
in May 2012 for subsea architecture applications, with line pipe and field
joint applications set to follow.
PipeAssure: lightweight adhesive for
pipeline repair
A number of products coming on to the market are emphasising the benefits
of composite materials for subsea operations. One such is PipeAssure, developed
by Malaysian national oil and gas company Petronas in partnership with the
Commonwealth Scientific and Industrial Research Organisation (CSIRO) in
Australia.
PipeAssure has been developed to address the difficulty of repairing and
maintaining underwater pipelines, which deteriorate under harsh subsea
conditions and often have to be patched up with welding operations, which can
often necessitate temporary but costly production shutdowns.
PipeAssure is an adhesive composite material that can be wrapped around
corroded or degraded pipelines to restore them to original design
specifications. The composite achieves this through its material make-up, which
begins as an epoxy-based resin system impregnated into a glass fabric before
curing into a fibre-reinforced composite.
The material can adhere to submersed steel substrates and, with a high
thermal softening point, endure the range of temperatures experienced in this
operating environment.
