possible, which often leads to huge development programmes
(cost, resource, gate approval and third party assessment),
combined with a hesitation to be “the first”. Despite this,
between the energy demand pushing us forward and the risk
of over stretching our technical capability within that small
space for new developments, technology is advancing.
Pushing the industry forward
In order to move forward, the industry will continue to push
developing solutions for deeper water, harsher environments
and more challenging well fluid compositions. To address
these core issues we need to address high cyclic loading
(fatigue), restricted access, remote operation, corrosion and
flow assurance induced by high pressure high temperature
(HP/HT) well fluid, and potential CO
2
and H
2
S content that
might change in concentration throughout the life of the
field. These issues bring unique challenges to drilling and well
completion, but they also have significant impact regarding
pipeline flow assurance i.e., the ability to produce fluids
economically, from the reservoir to a production facility, over
the life of a field.
To meet these flow assurance challenges, a number of key
developments in pipeline technology have occurred. Pipe-
in-pipe (PIP) systems, for instance, provide increased thermal
insulation to enable untreated well fluids to be transported
large distances. PIP products consist of the production
pipeline being sleeved into an outer pipe; the outer edge
remains dry and filled with a high performance insulation
material configured to meet project thermal requirements. An
outer pipe is designed to withstand the hydrostatic pressure
dictated by the water depth and the method of installation.
The use of exotic materials is becoming more
commonplace. Increasing the chromium content in the
material produces a range of duplex, super duplex and
stainless steels to manufacture pipelines, as these help to
maintain the pipe against corrosion. New material selections
have been pushed further by a number of companies that
have developed components made from carbon fibre, which
maintains a very high strength whilst remaining light, and
titanium which works as an excellent fatigue performer in
riser applications and the manufacture of stress joints. The
challenges of integrating these components into carbon
steel pipelines have also been explored, researched and
developed.
Plain carbon steel is simply not going to be a solution for
the future. Low strength carbon steels lead to thick walled
pipes that make heavy components – which in deepwater
is not a good option for riser, jumpers and tie-ins. As the
strength of the carbon steel increases, reducing wall thickness
and weight, welding becomes harder, reducing the number of
qualified suppliers that then drives up the cost.
From a simple view point, the future development of
pipelines could be in implementing the use of exotic materials
in hybrid systems. However, looking to the future, there are
critical issues that cannot be overlooked. How do we tie-in to
the system should we wish to in the future? How do we repair
the system should damage occur?
Every pipeline asset is at risk of failure: corrosion, erosion,
dropped objects, dragged anchors, damage during installation
or even internal blockages caused by unforeseen hydrate
formation. The probability of it happening is low, but the
potential consequences if it does happen are huge.
The loss of pipeline integrity not only presents a potential
environmental catastrophe, but also threatens the transport
link for hydrocarbons. An incident of this kind could result in
platform shutdowns and the loss of supply. An interruption
of supply could also have serious consequences for the end
user, with populations suffering supply loss. In order to reduce
risks, many operators have developed contingency stand-by
systems to minimise the downtime of damaged subsea
pipelines.
It would be commercially unviable to replace the entire
pipeline if damage occurs, so it needs to be the responsibility
of the owner and operator to have repair scenarios in place.
With carbon steel pipelines, emergency pipeline repair
systems (EPRS) can take the form of welding rigs, contracted
repair vessels, storage of mechanical connectors or clamps, or
even membership to private EPRS clubs.
EPRS is insurance to the asset owner. It is the process of
deciding on an emergency repair procedure and retaining the
necessary tooling, equipment and services before a situation
occurs. With this system in place EPRS can immediately react
to unplanned repair, minimising the resultant damage to the
environment and field operation.
When developing an EPRS system, contingency options
should be developed to accommodate each scenario. These
contingencies should include ancillary equipment, procedures
and generic risk assessments as well as the core isolation
tooling.
If you introduce new technology into the pipeline
industry, then new repair methods need to be developed
Figure 2.
Hydratight Mechanical Connector for diverless
(remote) installation.
80
World Pipelines
/
SEPTEMBER 2014
