World-class welding technologies - Subsea 7

Technology news from Subsea 7 - May 2012
World-class
welding
technologies
What’s inside...
02 Pipeline welding enhancements
04 New riser technologies
05 Precision performance on Pazflor
06 Groundbreaking geotechnics
07 Cutting-edge simulation
08 Mechanically lined pipe extends
reach
Subsea hydrocarbon sampling skid
09 Swaged end connection for reel-lay
pipe-in-pipe
10 Fleet development update
12 AIV commercialised
New multipass and backfill
ploughs
deep
seabed-to-surface

02
In-depth technology news
More than ever before, Subsea 7 continues to
commit to the development and commercialisation
of new technology, vessels and equipment that
deliver technical and cost-effective solutions to our
clients in their increasingly challenging environments
and operational scenarios.
Many of our most effective technologies are
developed in active collaboration with key suppliers
from our supply chain. Our development partners
play an important role in the emergence of effective
new ideas and solutions for our clients, and they
cover a unique range of technologies which reflect
our global expertise and capability.
We are proud to
have received
recent industry
recognition of one
of our pipeline
technologies
from the Pipeline
Industries Guild.
One of the industry’s
foremost bodies,
the Guild presented
Subsea 7 with the
prestigious “Subsea
Pipeline Technology Award” at their annual dinner
in London in March for our development work on
the installation of mechanically lined pipe using the
reel–lay method, (see page 8 for details of current
development work).
In this latest issue of deep7, you can read
about our latest applied technology advances
in disciplines ranging from pipeline welding to
geotechnics, and from advanced vessel design
to the installation of ground-breaking subsea
infrastructure.
To find out more about any of the
technologies featured in this issue contact
John Mair, Technology Development Director
at john.mair@subsea7.com or email
communications@subsea7.com
DEEP7 May 2012
Welding
enhancements
in the pipeline
Subsea 7 is developing and implementing leading-edge pipeline
welding technologies to satisfy evolving market demand - both
in terms of technical specifications and volume - and to meet
increasingly stringent pipeline fabrication codes and operator
specifications.
Underpinning this technology development are three important
strategic investments by the company:
• entering into a technical partnership with CRC-Evans Pipeline
International (CRC), one of the world’s leading designers and
manufacturers of automatic welding systems for pipeline
construction
• committing to an extensive welding R&D programme to meet future
industry demands
• the opening in 2013 of a new Global Welding Development Centre
in Glasgow, managed by Subsea 7’s Pipeline Production Group
(PPG).
Pipeline performance is currently being challenged on a number of
fronts – not only by high demands on the performance of pipeline
welding processes and the assurance of the integrity of girth welds,
but also by the increasing usage of higher strength steels, clad/lined
and solid corrosion-resistant alloy (CRA) pipe.
Subsea 7 is implementing a welding methodology which meets the
following criteria:
• Adoption of a common approach to welding processes and
equipment across all fabrication sites
• Use of welding processes which allow the heat input to be
controlled precisely to optimise weld mechanical and corrosion
properties whilst ensuring weld soundness
• Use of mechanised welding whenever practical in order to minimise
welder intervention.
Subsea 7’s reeled pipeline production facility at Vigra in Norway,
accommodates the latest mechanised welding technology, and

demonstrates how careful assessment of project requirements
and production factors can deliver cost-effective welding
solutions. The new technology is about to be deployed in
Brazil, and will thereafter be rolled out to Subsea 7’s other
fabrication sites worldwide.
In the case of larger-diameter carbon steel pipelines, the use
of the mechanised Pulsed Gas Metal Arc Welding (PGMAW)
process is now established as the welding method of choice
for both riser and flowline applications. The process utilises
low-heat input which results in excellent mechanical properties
in the girth welds.
The process can be deployed using either single torch, or in
the case of larger diameter pipe, dual torch welding in order
to improve productivity. This system is highly mechanised so
that the role of the welding operator is simply to supervise the
process with minimal intervention required.
Since the current welding system was introduced to Vigra in
early 2011, about 400km of carbon steel pipeline have been
fabricated, with productivity and quality exceeding targets.
The overall weld repair rate, which is a key quality indicator, is
less than 0.5%.
Subsea 7 has further developed the PGMAW process for use
in the fabrication of metallurgically clad pipe.
Welding of clad pipe requires the use of dissimilar welding filler
material, i.e. Alloy 625. Subsea 7 has carried out extensive
welding trials to optimise pulsed welding parameters and
shielding gas composition.
The qualified PGMAW solution makes use of the Controlled
Metal Transfer (CMT) process for root welding, an advanced
PGMAW technique which allows the weld root to be deposited
very precisely, giving good control of the root bead quality and
profile. These features are essential to maintain the corrosion
03
performance of the clad pipeline. During production, an
internal camera and laser profiling device is utilised to perform
an assessment of the quality of the root bead.
The developed welding solution will be implemented in
production this year for a number of pipeline projects, which
will involve over 70km of metallurgically clad and mechanically
lined pipe risers.
For smaller diameter pipes (4-inches and below) a mechanised
welding system has been developed by Subsea 7 and
implemented at Vigra. A key benefit of this system is to
provide a more precise control of the heat input in order to
maintain the optimum mechanical and corrosion performance.
This solution, initially deployed on a 2-inch duplex stainless
steel service line, was based on the use of the orbital Gas
Tungsten Arc Welding (GTAW) process using the Polysoude
welding system. Production welding has been in progress
since November 2011 with weld quality and productivity
meeting expectations, and has confirmed that this technology
can be successfully deployed on a global basis.
The 2-inch duplex line was also a Vigra “first” for the use of an
automatic arc monitoring system on the firing line to capture
and record the essential welding parameters.
Operations will begin in 2013 at Subsea 7’s new Global
Welding Development Centre in Glasgow, which will
incorporate 18 welding bays including facilities for J-lay and
S-lay pipeline welding, and will act as a central technical
authority for the development and qualification of all welding
procedures for all Subsea 7 pipeline fabrication bases around
the world.
This major initiative by Subsea 7 will give clients the assurance
of quality and delivery of pipeline welding performance at a
competitive cost.
For further information contact eric.law@subsea7.com
seabed-to-surface

04
New riser technologies
under construction
Many years of applied research and
construction experience have given
Subsea 7 the significant advantage
of being a SURF contractor capable
of providing all types of riser systems
for deepwater and ultra-deepwater
installation, depending on the field
architecture and client needs.
This in-house capability includes
design, procurement, construction,
installation and maintenance.
Riser systems installed on a worldwide
basis by Subsea 7 fall into two
categories - those coupled directly
to the host facility, and un-coupled
systems which in most cases are
connected to the host by flexible
jumpers and are increasingly being
applied in recent deepwater and ultradeepwater
field developments.
Subsea 7 continues to develop
innovative un-coupled riser concepts
designed for harsh and challenging
environments.
HRTs
Hybrid Riser Towers (HRTs) are
recognised to have significant benefits
for deepwater riser applications in
terms of flow assurance, thermal
performance and robustness of
layout. This latter issue is especially
significant when a large number of
risers are considered. An HRT provides
the required flexibility by avoiding
a crowded layout and allowing a
progressive deployment. The concept
is applicable to deepwater and ultradeepwater,
and to spread-moored and
turret-moored FPSO installations.
The first HRT application installed by
Subsea 7 was Girassol in Angola for
Total in 1998. The field, incorporating
three HRTs, has been producing for
over ten years to the specified stringent
flow assurance requirements.
HRTs have now become accepted as a
robust solution for deepwater and ultradeepwater
developments. The latest
Subsea 7 HRT technology is currently
being applied to Total’s CLOV projects
offshore Angola where two HRTs will be
installed in 2013.
For further information contact john.mair@subsea7.com
DEEP7 May 2012
BSR
The Buoyancy Supported Riser (BSR)
system is being delivered by
Subsea 7 for the Guará and Lula NE
field development in Brazil under
contract to Petrobras for installation in
late 2012/early 2013.
The BSR concept consists of a large
sub-surface buoy which is anchored
to the seabed by eight tethers, two on
each corner of the buoy. The buoy
supports multiple Steel Catenary Risers
(SCRs) which are connected to the
FPSO by non-bonded flexible jumpers.
This BSR system absorbs the dynamics
from the FPSO, resulting in almost no
dynamic stresses on the SCRs, making
them behave like a long free-spanning
pipeline with the major fatigue response
coming from the Vortex Induced
Vibration due to the local currents.
Since there is very little dynamic
response for the SCRs, mechanically
lined pipe is used for the SCR section,
thereby optimising the riser design.
COBRA
Subsea 7’s most recent riser concept
is the Catenary Offset Buoyant Riser
Assembly (COBRA), which consists
of a catenary riser section with a long,
slender buoyancy module on top which
is tethered down to the sea bed. Similar
to the multi–riser BSR, the top of the
catenary riser section is connected to
the host by a flexible jumper.
COBRA is a highly compatible riser
arrangement for host platforms with
large motions, like FPSOs or semisubmersibles.
This riser concept has the advantages
of excellent dynamic performance with
little or no fatigue response, and can
therefore be designed for pipelineclass
welds. This therefore allows the
use of mechanically lined pipe where
appropriate, as in the case of the
Buoyancy Supported Riser.
Other riser systems such as Grouped
SLOR and Single Hybrid Risers are also
part of Subsea 7’s un-coupled Riser
portfolio.
Hydrid Riser Towers (HRTs)
Buoyancy Supported Riser (BSR)
Buoyancy
SCR
Jumper
Mooring lines
Catenary Offset Buoyant Riser Assembly (COBRA)

Planning and precision
combine on Pazflor
The successful installation by
Subsea 7 of three subsea separation
units (SSUs), operated by Total E&P
Angola, proved critical to the early
completion of the landmark Pazflor
project on Block 17, offshore Angola.
The challenging project involved the
world’s first deployment of vertical
SSUs to separate the oil, gas and
water produced from Pazflor’s
Miocene reservoirs.
Installing each SSU (weighing in excess
of 1,000t, including suction anchors)
required an unprecedented level of
precision in water depths around 800m
and a close working relationship with
Total and the SSU manufacturer, FMC,
to ensure the final design included
offshore installation requirements.
Operational requirements necessitated
exceptionally tight installation
tolerances of +/- 0.5° from horizontal
when installing the cluster of four
suction anchor foundations. To achieve
this target, Subsea 7 developed the
lifting arrangement, and interfaced with
FMC to accurately operate the levelling
system based on differential suction.
Early analyses showed a risk of
resonance of the subsea hardware
during lowering, potentially leading
to significant weather sensitivity. To
mitigate this issue, Subsea 7 developed
a real-time monitoring system receiving
acceleration data from sensors located
on the crane tip and on top of the
hardware as they were lowered.
Extensive dry and shallow water testing
in Norway allowed the team to test
the SSU installation before the units
were finally transported to Angola.
Working in close liaison with FMC,
Subsea 7 coordinated transportation
and designed a specific sea fastening
to minimise fatigue of the SSUs. Prior
to deployment on site by Subsea 7’s
installation vessel the Acergy Polaris,
the structure’s integrity was re-tested in
Luanda bay.
Connecting each SSU to the subsea
manifold was a complex and delicate
operation in which the ROV operators
had to first remove caps from the
SSU shallow water tests in Norway
manifold followed by the operation of
a jacking system to slide the 400t, sixstorey
high SSU towards the manifold to
mate three connections simultaneously.
The Seven Eagle performed the SSU
umbilical installation and the tie-in of the
first pair of four multi-phase pumps.
The landmark project, in which first
oil was achieved ahead of schedule
including the development and
installation of new technology,
underlines the importance of effective
interfaces between suppliers,
contractors and client.
Subsea 7 continues to develop new
deployment systems including fibrerope
and active-heave compensation
that are deemed essential in the
deployment and retrieval of sensitive
rotating machinery and processing
systems in ever-increasing water depths
of the future.
A Pazflor SSU being installed
05
seabed-to-surface

06
Groundbreaking geotechnics
In 2011, Subsea 7 commenced
accelerated development in the
field of Geotechnics in two areas of
great significance for our clients’
deepwater operations, how seabed
soils and pipelines interact, and how
an enhanced appreciation of soil
behaviour and failure mechanisms
can optimise foundation design,
particularly for very soft deepwater
clays.
Pipelines
Subsea 7 actively participates in the
Safebuck series of JIPs - currently in its
third phase - but we have also internally
funded work investigating the dynamic
embedment (and hence friction and
stability) of pipes laid on soft clays which
are typically found at the deepwater sites
where we work.
Another key challenge being addressed
is an improved understanding of the
behaviour of carbonate sediments which
are widespread in some developing oil
and gas-rich regions such as Australia.
Carbonate-rich soils exhibit different
behaviour to their non-carbonate
counterparts, so Subsea 7 undertook
a study to investigate the response of
carbonate soils to cyclic pipe loads
by model testing in a geotechnical
centrifuge.
Model pipe set up for axial friction test
The results of this study are counterintuitive
to those predicted by classical
soil mechanics, and the work represents
a significant step forward in evolving a
new constitutive model to describe the
behaviour of carbonate soils.
For further information contact paul.brunning@subsea7.com
DEEP7 May 2012
Apparent friction derived from cyclic axial friction tests
Foundations
In our subsea construction business,
there is constant pressure to optimise
foundation design to be as efficient as
possible in terms of installation without
compromising functionality.
Subsea 7 has produced recent research
at the highly respected Centre for
Offshore Foundation Systems at the
University of Western Australia into an
optimised design methodology that has
led to the possibility of reducing the size
of shallow foundations such as PLET
mudmats by 20%, or alternatively able
to withstand larger jumper loads.
The geotechnical engineer is always
interested in finding the most critical
failure mechanism of a foundation.
Subsea 7 has teamed up with the
university to develop a new 3D analysis
tool which could potentially halve the
engineering hours spent designing
foundations under complex loading.
FE analysis for optimised foundation design
Mudmats for PLET applications
Looking to the future…
Emerging challenges in the
geotechnical industry are likely to
include:
• developing and improving
the constitutive model for
carbonate soils and applying
it to foundation and pipeline
design
• how to quantify the degrading
effects of solid hydrate and
hydrate dissociation on soil
properties
• further optimisation of
foundation designs as large
and heavy processing facilities
are moved subsea
• developing design methods
for ultra-deepwater soils where
soil strength is more dominated
by viscous behaviour than
traditional shear strength
• finding novel and effective
ways to protect subsea
infrastructure in the Arctic or
ice-prone regions.

Cutting-edge simulation
Subsea 7 has developed one of the
most powerful installation simulation
packages ever built, including
unique finite element analysis
(FEA) capabilities, and successfully
installed the hardware on board
construction vessel the Seven
Seas for effective on-site operative
training.
The programme was developed over a
two-year period for the Block 31 project
offshore Angola. An unusual aspect of
this deepwater project is the mid-water
pull-in of the flexible risers that connect
the vertical risers to the FPSO. These
operations are carried out at an average
depth of 200m, which presented
uncommon problems.
Unlike most pull-ins, the tasks are
performed in a situation where
everything in the scenario is mobile.
The Upper Riser Assembly (URA), while
weighing several hundred tonnes, can
be easily moved and rotated should the
ROV push it. When the flexible risers
are attached to the subsea winch wires
and the load transferred from the vessel
crane to the winches, the URA, which
in itself is dynamic, tends to follow the
riser lay direction for many metres -
which has the potential to compromise
the minimum bending radius (MBR) of
the flexible.
The situation was risk-assessed, and
it was decided that the risks could be
mitigated by building the nine different
scenarios (there are nine flexible
risers) in a simulator. This would allow
procedures to be checked, and also
facilitate pilot training. The simulation
predictions were shown to correlate well
with measurements taken before and
during the actual offshore operation.
The development of the simulator
though 2010 and 2011 pushed the pilottraining
software and hardware well
beyond their existing capacity, due to
the large number of flexible and moving
objects in each scenario.
Most simulation training takes place at
Subsea 7’s site in Aberdeen, but for this
project it proved more effective to train
the ROV pilots, superintendents, and
Block 31 installation simulator in use on board the Seven Seas
bridge supervisors on board the Seven
Seas, in an environment with which they
are already familiar.
The simulations feature:
• Variable sea conditions which can
produce realistic motions of the
Seven Seas (Subsea 7’s construction
vessel on Block 31)
• Sea currents that can be varied
in both strength and direction at
different depths to replicate the
currents throughout the entire
2,100m water column
• Two Hercules ROV systems, each
with fully working manipulators and
three selectable onboard cameras
• Real-time FEA package calculating
loads on, and MBR of, the flexibles
• Two subsea winches complete with
working line-out meters and load
cells.
The simulation FEA calculates the minimum
bending radius of the flexible during ROV
operations
07
The on-board simulator uses the
existing Hercules 23 control console,
with an additional six powerful PCs. A
switch disconnects the topside control
system from the ROV and changes
operations from normal ROV control to
simulation mode (this is only done when
the vehicle is on deck!).
For further information contact mike.bramley@subsea 7.com
seabed-to-surface

08
Mechanically lined pipe extends reach
Subsea 7’s ground-breaking development work into the
installation of mechanically lined pipe has recently been
undergoing further qualification following the world’s
first contract award to use BuBi ® mechanically lined pipe
installed by the reel-lay method for the Guará and Lula NE
pre-salt project in Brazil.
Working in collaboration with BuBi ® manufacturer BUTTING,
Subsea 7 has already qualified BuBi ® mechanically lined
pipe for reel-lay installation for flowlines and low-fatigue riser
applications globally as a cost-effective alternative to solid
corrosion-resistant alloys or metallurgically clad pipe. We are
now broadening the product’s applications into areas of higher
pressure and fatigue applications.
Current testing has demonstrated higher fatigue performance
to DNV class C/2 at the time of print to extend the applicability
of the technology to even greater water depths and more
challenging design criteria.
The rigorous fatigue testing programme included:
• Manufacture of three test strings (12 girth welds) comprising
carbon steel grade X65 for the outer pipe and alloy 625 for
the liner, made up of BuBi ® pipe sections welded together
using the mechanised PGTAW process (see page 3) with
alloy 625 filler metal
• A conservative cyclic bending test or reeling simulation,
using a radius of curvature of 7.5m
• Resonance fatigue testing of the string post-reeling
simulation. The endurance of the pipe and its welds was
thus confirmed to achieve the minimum target level of
fatigue class C/2.
DEEP7 May 2012
The full programme was
performed in accordance with
DNV Qualification (DNV-
RP-A203) and was previously
awarded the certificate for
‘fitness for service’.
An extensive NDE validation programme was conducted
between Subsea 7 and BUTTING to qualify the inspection
technology (DNV) and demonstrate the capacity to detect any
minute defects in the pipe end overlay welds and seal weld at
the transition between liner and overlay.
The combination of the high-quality manufacturing process and
inspection technology is fundamental to ensure the in-service
reliability of the technology.
Subsea Hydrocarbon Sampling Skid (SHSS)
Following the successful
development of its
Subsea Hydrocarbon
Sampling Skid (SHSS),
Subsea 7 is now able
to offer clients ROVdeployed
sampling from
live production wells
with zero emissions
to the environment
while maintaining full
isothermic and isobaric
conditions.
Hydrocarbon samples are required in order to determine
fluid chemistry to enable calibration of the subsea flowmeter
and potential fiscal allocations. The Subsea 7 SHSS takes
a true sample with no need to alter production flow or
temperature.
It also takes samples from individual wells before they
are mixed together at manifold or FPSO, and enables
production samples or gases from individual wells to be
analysed independently.
The Welding Institute (TWI)
Fatigue Test Rig
S-N curves showing the number of
fatigue cycles reached to date on three
test strings (RF1, RF2, RF3). No failure
of the pipe or liner seal welds has been
recorded at the DNV class C.
For further information contact gregory.toguyeni@subsea7.com
The skid comprises the following key elements:
• A number of sampling cylinders allowing several samples
to be taken from multiple locations/wells
• A controlled rate of fill and heating system ensures the
sample is taken in an isobaric and isothermal manner.
• The host ROV provides the skid with power and telemetry.
• Topsides control is via a robust laptop PC.
• A heating system maintains the sample cylinders and
pipework at a sufficiently elevated temperature in order
to mitigate the formation of hydrates during the sampling
process and dissolved gases coming out of solution.
• A fail-safe connection tool ensures the safe shutdown
of the sample interface at the well should the ROV
experience a vessel run-off or dead vehicle situation.
The SHSS is the latest in a long Subsea 7 tradition of
developing pioneering high-quality, cost-effective ROV
tooling, including a standard range of manipulator-deployed
tools, component change-out tools, bespoke intervention
tools and skids.
For further information contact mick.fowkes@subsea7.com

Swaged end connection for reel-lay
high performance pipe-in-pipe
In collaboration with its development partner ITP InTerPipe,
Subsea 7 currently offers the market its DNV-qualified
Enhanced Thermal Performance Pipe-in-Pipe system for
installation by the reel-lay method. This superior technical
solution, which benefits from the combination of Izoflex
insulation material in conjunction with a reduced pressure in
the PIP annulus section, has recently been further enhanced
by the development and qualification of the Swaged Field
Joint.
The Swaged End Connection has already been widely used by
Subsea 7 on J-lay and S-lay PIP projects, but this new concept
relates to reel-lay applications.
The Swaged End Connection is fabricated by swaging the
pipe ends of the outer sleeve pipe, followed by welding to the
flowline at each end of the fabricated stalk, typically 750m long
for reel-lay applications. The sealed annulus within the stalk
can then have the pressure drawn down within the annulus offline
in advance of reeling onto the reel-lay vessel.
As each stalk is subsequently reeled onto the vessel, the PIP
swaged end stalks are fabricated together by firstly girthwelding
of the flowlines and the use of welded half shells for
the outer sleeve pipe.
The Swaged End Connection’s primary function is to provide
the following:
• A leak-tight seal for draw-down of pressure within the
annulus
• A robust mechanical barrier to act as a water stop in all
envisaged water depths in the event that the outer pipe is
breached, thus preventing the entire pipeline annulus from
flooding
• A means of mechanical connection between the flowline and
outer sleeve pipe that can be reeled.
Testing and qualification
has focused primarily on
the following areas in order
to attain DNV “Fitness for
Service” Qualification in
compliance with DNV-RP
A-203:
• FEA modelling
• Simulated reeling and straightening trials
• Welding and inspection
• Post-reeling FEA analysis using strain data collated from the
simulated reeling and straightening trials
• Material testing
• Annulus pressure test
Enhanced Thermal Performance PIP incorporating
Izoflex insulation material with reduced pressure and no
centralisers in the annulus section
Sleeve Pipe
Flowline
Pipe-in-Pipe cross section
FE analysis
Svalin C reeled PIP
Subsea 7’s expertise in high performance Pipe-in-
Pipe (PIP) installations covers full-scope design,
procurement, construction and installation, and extends
to over 40 successful PIP projects including bundle
technology, S-lay, J-lay and reel-lay.
Our latest project comprises a 5-inch/8-inch gas lift
Pipe-in-Pipe, to be designed, constructed and installed
for Statoil between the Svalin C Template and the
Grane platform in the central North Sea. The contract
also covers the installation of the Svalin C template and
manifold, a highly wet-insulated production flowline,
and an umbilical.
In addition to our market-leading versatility in the
installation of high performance Pipe-in-Pipe, Subsea 7
can also install electrically trace-heated flowline (ETHF)
PIP solutions by reel-lay or in towed bundles.
ETHF technology has been successfully
commercialised by Subsea 7 in partnership with
manufacturer ITP InTerPipe to combine highperformance
thermal insulation with low-power resistive
heating elements. Now technologically qualified by
DNV for reel-lay installation, ETHF offers a highly
efficient means of maintaining product temperature in
the most challenging subsea environments.
09
For further information contact paul.booth@subsea7.com
seabed-to-surface

10
Fleet development update
Subsea 7’s industry-leading commitment to fleet
development is directly driven by our identification and
anticipation of our clients’ needs for their increasingly
challenging subsea field developments.
Whether for highly complex deepwater installations, extended
Life-of-Field operations or enhanced welding performance,
Subsea 7 is committed to working in close collaboration with
our vessel-build and equipment partners to incorporate client
requirements in the design of new vessels and upgrading of
existing vessels.
The five new vessels profiled here all reflect, in their different
ways, elements of our commitment to deploy a fleet of
New-build
Seven Borealis
With its pipelay and heavy-lift
capabilities, Subsea 7’s Seven
Borealis is possibly the most
versatile offshore construction
vessel. Its 5,000t crane, with
the top of the mast reaching
150m above the main deck,
is the world’s largest offshore
mast crane. Recent lift
tests in Singapore proved its
capability of lifting 5,000t.
The Seven Borealis joins the
fleet in the second half of
2012.
New-build flexible pipelay support vessel (PLSV)
Subsea 7 has been awarded a contract to provide a 550t
top-tension PLSV for Petrobras for delivery in 2014. This
top-tension capability gives the vessel Subsea 7’s highestperforming
flexible pipelay capability in the fleet, and among
DEEP7 May 2012
unrivalled capacity and versatility, and one which offers our
clients access to over 40 vessels with the highest standards of
flexibility and project reliability.
Enhanced vessel specifications like crane and moonpool
capacities are designed to accommodate the hardware which
we plan to deploy for the future in support of our clients.
This is particularly evident in our latest flagship enabling vessel,
the Seven Borealis, which not only features world-leading
lifting capabilities, but will also incorporate Subsea 7’s latest
mechanised welding technologies on its J-lay and S-lay firing
lines (see pages 2 and 3).
the highest for any PLSV in the world. This high specification
reflects the existing and anticipated demand of Brazilian ultradeepwater
operations.
The vessel is scheduled to have a 550t Tiltable Lay System
(TLS) installed, with two 275t retractable tensioners to handle
flexible products between 100mm and 630mm outer diameter.
The tower can tilt to 10o when operational to recover rigid pipe
from the seabed but it can also tilt to 50o from the vertical to
allow the TLS to clear power cables across the entrance to
Vitoria harbour.
The two underdeck carousels will also be of the open-top
“basket” design. The new PLSV also incorporates a number of
further design innovations to meet the specific requirements of
the Brazilian market. The vessel will be fitted with underwater
demountable thrusters which can be removed and replaced
while the vessel is afloat.

Seven Viking
Due for launch in late 2012, the Seven Viking is designed as a “next
generation” Inspection, Maintenance and Repair (IMR) vessel, with
enhanced seakeeping qualities and environmental performance. The
Seven Viking will enter a long-term frame agreement with Statoil for
operations in the North, Norwegian and Barents Seas.
The Seven Viking incorporates a number of design features to minimise
mobilisation times and optimise transit speeds, most notably an
innovative hull shape which offers increased foreship volume and
slender waterlines. As well as offering improved seakeeping capabilities
(fully operational in 5m significant wave height), this design also provides
a larger working deck area, with a raised freeboard and working stations
enclosed in a heated indoor hangar to enable IMR operations in rough
seas and extreme temperatures.
Other innovations which facilitate harsh weather operations include a
skidding module handling system to store and move up to eight different
modules into the moonpool, eliminating the risk of hanging loads, and
de-ice facilities and a strengthened hull for operations in Arctic areas.
Seven Inagha
Subsea 7 has an impressive track record in
developing innovative equipment, and this is
confirmed by a new vessel joining the fleet in 2012.
The Seven Inagha started her life in 2011 as a
high-capacity Gulf of Mexico liftboat. During her
construction, she was purchased by Subsea 7 and
began her conversion into an extremely capable
platform for hook-up operations in West Africa.
The Seven Inagha is effectively a vessel with
legs, and, unlike most conventional jack-ups,
can mobilise to a work site under her own power.
She has an impressive lifting capacity with two
295t cranes fitted, and will commence operations
offshore Nigeria. With enhanced facilities able to
accommodate up to 150 people on board, she will
provide utility services and support to hook-up
teams on offshore installations.
The three eye-catching tubular 97.5m legs have
pairs of racks which allow the 36 planetary motors
to jack the hull at a speed of 2.4m per minute,
elevating the hull to a maximum height of 88m
above the seabed in water depths of up to 76m
when operating in hook-up mode.
Seven Havila
The state-of-the-art diving support vessel, the
Seven Havila, which is owned by Subsea 7 and
Havila Shipping and is widely considered to
be the most advanced
vessel of its type in the
world, has achieved
a world first by
simultaneously deploying
eight saturation divers
from a single vessel.
The advanced diving
system on the vessel includes a ten-chamber,
24-men fully computerised saturation suite,
with a double bell handling system capable of
working down to 400m and up to 6m significant
wave height.
11
seabed-to-surface

Autonomous Inspection Vehicle (AIV) commercialised
Following extensive inwater
testing in 2011, the
final software systems
and design adjustments
on Subsea 7’s pioneering
Autonomous Inspection
Vehicle (AIV) have been
implemented, and
this game-changing
technology is now
being successfully
commercialised.
The Mark 1 inspectionclass
vehicle is being
deployed into customer
qualification programmes AIV deployment system
during 2012, and the
development paths of the next generations of fully capable,
work-class sized intervention vehicles are already being laid.
A differentiating element of the AIV is its ability to recognise
and respond to its surroundings - it will correct its trajectory in
real time, based on the information it gathers from its onboard
sensors. This level of intelligence and decision-making has had
to be de-risked and made as robust as possible, so a powerful
virtual reality simulator was used to ensure that every option was
identified and assessed.
New multipass and backfill ploughs
Subsea 7 has recently invested in two high-performance
subsea ploughs that will significantly enhance our delivery
capability on the burial of trenched pipelines.
Our new Variable Multi-Pass Plough (VMP), as the name
suggests, has the capability to perform a number of passes
through the seabed to achieve the specified depth. However,
where the VMP has a significant advantage over other ploughs
is in its ability to alter its cut depth without recovery, thereby
reducing operational timings.
Another design innovation is the VMP’s fore-cutter, in front of
the main cutting tool, which enables this plough to function in
stiffer soil conditions.
The VMP already has a proven track record, completing an
extensive variety of pre- and post-cut trenches in varying soil
www.subsea7.com
DEEP7 May 2012
Variable Multi-Pass Plough
© Subsea 7, 2012. Information correct at time of going to press.
In collaboration with one of the world’s leading underwater
simulator suppliers, a detailed specification was developed
to allow “hardware-in-the-loop” testing. The final system,
probably one of the most sophisticated in existence, allows
the real AIV computational hardware to control a dynamic
simulation model of the AIV within a virtual world that
contains a full 3D representation of an offshore oilfield. This
package provides full emulation of the sensor packages
and simulation of the vehicle dynamics operating around
representative subsea infrastructure.
Although this simulation uses a bank of some of the fastest
industrial computers available, it allows AIV missions to
be run hundreds of times to ensure that the AIV decisionmaking
behaviour is robust.
The visual inspection capability of the AIV Mark 1 will lead
to more cost-efficient and effective integrity management
throughout the lifetime of a subsea field development.
As customer qualification of the visual inspection vehicle
proceeds, Subsea 7 is simultaneously engaging with
subsea developers, industry bodies and field development
strategists to explore how autonomous technology can
further enhance the challenging subsea operations of the
future.
For further information contact hugh.ferguson@subsea7.com
conditions around the world for large-diameter pipelines,
trucklines and flowlines.
To complement the VMP, Subsea 7 has also invested in a
Backfill Plough (BFP), which redeposits the soil from the VMPcut
trench back into the void once the product is laid. The
ability to provide a quality backfill with the BFP significantly
enhances both the thermal insulation and resistance to
upheaval buckling.
Backfill Plough 2
The ploughs have already been deployed by another recent
addition to the Subsea 7 fleet - the highly versatile Skandi
Skansen which, with a 250t heave-compensated crane, a
300t A-Frame and a bollard pull of 350t, is ideally suited to
support many field installation operations, including ploughing
campaigns.
For further information contact farquhar.mitchell@subsea7.com