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Deepwater Pipeline and Riser Installation by the Reel-Lay Method

S N Smith and A J Clough, Subsea 7
Copyright 2010, Offshore Technology Conference
This paper was prepared for presentation at the 2010 Offshore Technology Conference held in Houston, Texas, USA, 36 May 2010.
This paper was selected for presentation by an OTC program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been
reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material does not necessarily reflect any position of the Offshore Technology Conference, its
officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Offshore Technology Conference is prohibited. Permission to
reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of OTC copyright.

Abstract
The reel-lay method is generally the most effective way of installing infield subsea flowlines and risers particularly for sizes
up to around 16 inch. This paper describes one of the most advanced reeled pipeline installation vessels in the world, the
Seven Oceans, and the variety of pipelines and risers that she has installed including the welding and inspection of high
fatigue life SCRs and sour-service flowlines.
The paper goes on to present various recent developments for reeled installation including HFI pipe, PE lined pipe,
mechanically lined pipe, clad flowlines and SCRs, high strength pipe, hybrid risers and electrically heated-traced flowlines.
These show the continuing attraction of reel-lay for ever more technically demanding work and that for options such as
electrically heat-traced flowlines that reeling will be the main vessel based installation method.
1. Introduction
1.1 Vessels
The reeled pipelay concept has been in use since the Pipelines Under the Ocean (PLUTO) project across the English
Channel (Purvis, 1946). The reel ship Apache (Anon, 1979) is a notable name in the development of the technology and was
first operated in 1979. Other reel lay vessels followed including the Skandi Navica (Clarkson, 2006) now named as Seven
Navica. Another notable vessel was the Deep Blue (De Soras & Cruickshank, 2000) and more recently the Seven Oceans.
Other reeled vessels also exist but the characteristics of these main ones are given in Table 1.
Vessel Name
Vessel Type
Length
Breadth
Depth
Draught
Reel Hub Diameter
Reel Capacity
Installed Power
DP Power
Accommodation
Top Tension
Crane
ROVs

Apache
Rigid Reel Lay
122.91m
23.34m
8.69m
5.55m
16.44m
2,000te
15.09MW
10.74MW
95
156te
[197te including back
tension to reel]
27te
-

Table 1:- Reel Lay Vessel Main Characteristics

Seven Navica
Rigid Reel Lay
108.53m
22.00m
9.00m
7.17m
15.00m
2,200te
12.60MW
9.80MW
72

Deep Blue
Rigid Reel Lay
206.50m
32.00m
17.80m
10.00m
19.50m
2 x 2,700te
33.60MW
25.60MW
160

Seven Oceans
Rigid Reel Lay
157.30m
28.40m
12.50m
7.50m
18.00m
3,500te
18.90MW
15.85MW
120

205te

550te

400te

60te
Option

400te
2 x 3,000m

400te
2 x 3,000m

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1.2 Spooling & Welding

One of the main attractions of reel-lay is that all the welding and inspection can be done onshore in well controlled
conditions at the spool base off the vessel critical path.
Spool bases are typically laid out so that long stalks, typically about 1 km long, can be pre-fabricated ready for spooling
prior to the vessel arrival.
The spooling itself is a rather unique operation in which the stalks are loaded on to the ship by bending them plastically
around the reel. The analysis and technology for this are well known and is constantly being refined (Denniel, 2009,
Transcheit, 2009) but it does of course mean that the extra loading has to be considered during the critical engineering
assessment and establishment of weld acceptance criteria.
For welding the generally adopted approach is to ensure that the pipeline girth weld overmatches the strength of the
parent pipe material. In order to ensure this, weld consumables typically require yield strengths in the order of pipe material
SMYS + 15ksi.
Additional strain age testing is commonly carried out replicating the
strain levels imposed during reeling and installation. This can be carried
out by full scale simulated reeling trials, see Fig. 1, or a replication of the
cyclic strain on small test strips.
This additional testing is generally applied to weld procedure
qualification, and fracture toughness testing simulating the end of life case
in the engineering critical assessment.
Welding operations are generally automatic in order to replicate high
mechanical integrity in each pipeline girth weld.
Fig. 1 Simulated Reeling Trial

1.3 Pipe Specifications

To optimise the production process the installation contractor typically requires tight end tolerances for the pipes to
supplement the clients specifications to reduce mis-match and reduce the time and space required for end-sorting and
alignment operations prior to welding.
For a typical flowline 1.0 mm on the ID is specified. The steel mills can reliably supply this up to around 10inch
diameter but above this, with seamless pipe, the actual delivered tolerance tends to creep out to around 1.4 mm and for
thicker deeper water pipe there does tend to be increased mill rejections on the larger sizes. With HFI pipe the mills can
supply to a tighter tolerance over a larger range of sizes. Some seamless mills are also currently promising 0.75 mm for
flowlines.
For SCRs even tighter tolerances are beneficial and help deliver the required fatigue life. Tolerances of 0.25 mm can be
obtained with upset forged ends such as the so-called PURE ends (Premium Upset Riser Ends), as used on the MARS project
(by others), or statistical sorting with an ID/OD machining operation.
Although some of these operations lead to higher mill procurement costs they can, when clients specify tight and onerous
fabrication or fatigue requirements, lead to lower installed costs.
2. Seven Oceans
The Seven Oceans with her constituent equipment is illustrated in Fig. 2. She was contracted in May 2005 and delivered
complete in July 2007.
The vessel is capable of carrying up to 3,500te of rigid pipe and laying in water depths down to 3,000m. The pipe is
stored on a midships mounted reel recessed into the vessel with a flange diameter of 28m, core diameter of 18m and a usable
width of 10m. The stern mounted pipelay ramp can be inclined forward to suit the departure angle of the pipe catenary for the
water depth and fleets across the vessel to match the transverse position of the pipe departing the reel. The pipe lay rate is
controlled during the lay operation by a single linear tensioner with a 400te dynamic capacity (500te holding capacity). The
pipe hang off clamp is installed below the ramp at the stern of the vessel and has a holding capacity of 600te.

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PLETs are handled using a dedicated PLET handling system. This system consists of a deck mounted rail system, a PLET
manipulator and a PLET line-up tool.
For planned (or unplanned) laydown of the pipe, a 450te A&R system is installed. The storage winch is capable of storing
3,000m of 119mm wire. The secondary A&R system has an 80te rating. The smaller wire enables the numerous smaller jobs
to be more readily handled on deck and subsea.
The Seven Oceans has a diesel electric propulsion system with power supplied by six diesel electric generator sets, three
in each of the two engine rooms. Each generator can run on either MGO or IFO to reduce costs. In transit, propulsion is
provided by three stern azimuth thrusters. In DP operations, station keeping is assured by the three stern azimuth thrusters
and at the bow, two drop-down azimuth thrusters and a tunnel thruster. The system has DP Class II notation but the as-fitted
specification is well in excess of the requirements making the vessel well suited for work adjacent to platforms such as SCR
hand-over operations.

Fig. 2 Seven Oceans General Arrangement

The main offshore mast crane is installed on the port side of the vessel just aft of amidships and has a main hook with
capacity of 400te at 16.5m radius and a 50te whip line. An auxiliary crane with a capacity of 40te at 14m radius is installed
amidships on the starboard side of the vessel and two 12te cranes are installed aft to facilitate pipelay operations.
The aft deck of the vessel between the reel and the ramp has an area of 650m and has a strength rating of 10te/m. The
deck thickness has been increased to 25mm to allow for wastage associated with repeated seafastening of items and
subsequent removal and there are no fuel tanks immediately below the main deck so that hot work is facilitated.
Two work class ROVs are installated in a hangar situated at the aft end of the superstructure. Each ROV has an
independent LARS and umbilical allowing operations in 3,000m water depth.
A helideck suitable for Sikorsky S-61 or Super Puma is situated forward, above the level of the bridge.
Further details can be found in Smith & MacGregor, 2006, MacGregor et al 2009, Smith et al 2009.

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3. Pipeline & Risers Installed by Seven Oceans

3.1 Blind Faith
The Blind Faith development in the Eastern Gulf of Mexico in water depths between
1,980 and 2,100 metres was the first project for Seven Oceans and its lines were installed in
Autumn 2007 around 30 months from the announcement of the build programme. The main
scope of work was the engineering, procurement and installation of 14km of rigid flowlines
(14km) and two Steel Catenary Risers (2.6km). The SCRs were as follows:
2 x SCRs in API 5L X60
7.625 (193.7mm) x 25.4mm
7.625 (193.7mm) x 20.6mm
Fig. 3 Seven Oceans on Blind Faith

Further details of the general installation work are given by Hensley 2008 and are illustrated in Fig. 3.
The welding of these SCRs presented significant challenges due to the stringent acceptance criteria. The welding method
adopted was pulsed hot wire automated GTAW. This was selected for two main reasons:High weld quality;
High mechanical integrity.
Tables 2 and 3 show the mechanical properties achieved on SCR projects with this process. All test values given are
averages of three.
Location
Weld Metal
Weld Metal
Weld Metal
HAZ
HAZ
HAZ

Test Temperature
-5C
-5C
-5C
-5C
-5C
-5C

As Welded CTOD (mm)

1.59
1.69
1.70
1.83
1.63
1.50

Post Reeled CTOD (mm)

1.55
1.72
1.51
1.77
1.67
1.62

Table 2 CTOD Values

Note: Specification Requirements: 0.51mm minimum average
Location

Test Temperature

As Welded Charpy Impact (J)

Post Reeled Charpy Impact (J)

Weld Metal
HAZ

-18C
-18C

425
408

434
431

Parent Material

-18C

412

436

Table 3 Charpy Impact Values

Note: Specification Requirements: As welded 41 J minimum average; Post reeling 53J minimum average
Both of these sets of results show clearly that the reeling process has no detrimental effect on these mechanical
properties.

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3.2 Tombua Landana

Tombua Landana situated in Block 14,
offshore Cabinda, Angola with comparatively
shallow water depths between 270 and 370
metres is another example of a project with
extensive reeled flowline installation. The
scope included the following:- 2 x 10 production flowlines;
- 1 x 8 test flowlines;
- 1 x 12 water injection line;
- 1 x 6 gas lift line;
- 10 x flexible jumper;
- 10 x pipeline end terminations;
- 1 steel tube umbilical and flying leads;
- 1 x 6 slot production manifold;
- 1 x 6 slot water injection manifold.
Fig. 4 Welding at the spoolbase in Luanda.

The scope was split between 2008 and 2009. All the reeled flowlines were installed by the Seven Oceans after fabrication
at the Luanda spoolbase (see Fig. 4) where the production welding was 100% done by Angolan welders.
3.3 Sour Service Flowlines
In Brazil two projects have been reel layed in which the flowline welds had to be qualified for sour service. On the first
the API 5L X65 pipes ranged from 273.1 mm diameter, 22.2mm w.t. to 323.9mm diameter, 28.6mm w.t. On the second the
pipes were X60 all 323.9mm diameter with wall thickness from 17.5mm to 25.4mm.
Resistance to sulphide stress corrosion cracking was established by first cyclic strain ageing (at strain levels duplicating
the installation of the worst case scenario) then testing in accordance with NACE TM 0177 with solution B and four point
bends in accordance with EFC-16. These tests were carried out at 85% of the specified minimum yield strength of the base
material. Welds had to comply with NACE MR 0175 / ISO 15156.
This demonstrates that welds can meet the requirements for sour-service after reeling.
3.4 BC10
BC-10 is located in the Campos Basin, offshore Brazil, in water depths between 1,600 and 2,000 metres including the
worlds first lazy wave SCRs (Hoffman et al 2010). The scope of work was the engineering fabrication and installation of
-

11 pipelines totalling approximately 130km

7 steel catenary lazy wave risers totalling approximately 21km;
3 dynamic and 2 static umbilicals totalling approximately 55km;
installation of 4 manifolds and 25 rigid jumpers.

Installation in progress is shown in Fig. 5.

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Fig. 5 Seven Seas and Seven Oceans working together on project BC-10.

Of particular relevance here all 130km of flowlines were reeled as were the 7 lazy
wave SCRs. The main particular of the SCRs as shown in Fig. 6 were as follows.
-6 off API 5L X60, 6 x 15.9mm
-1 off API 5L X65, 12 x 19.1mm

Fig. 6 Lazy Wave SCR Schematic

Obtaining the required fatigue life for SCR welds is a considerable

challenge and requires attention to all aspects of production and inspection
including miss-match of pipe ends, weld profiles, allowable defect size, and
correct interpretation of inspection results. The approach of one operator is
described in Kopp et al, 2003.

Fig. 7 Installing VIV Strakes

WeldingTorchOscillation

Pulse

Weld

For BC10, pulsed hot wire automated GTAW was used again with pulsing
Fig. 8 Weld Schematic
focused at the bevel to ensure full fusion at each side wall, see Fig. 8. The
allowable weld defect size was on the limits of detectibility with current AUT systems.

Production welding rates increased significantly and spurious cut-outs reduced during the project due to close liaison with
the client and the use of on site macro sectioning and evaluation to help calibrate the AUT results.

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4. New Technology for Reeled Installation

4.1 General
Reeled installation of pipelines has been in use for a considerable number of years. The majority of the pipes installed
have been seamless carbon steel such as API X52, X60 or X65. However other options to offer more cost effective solutions
or to cater for more aggressive fluids and other operating requirements are being developed. Before describing these we
should first mention some important internal technology.
4.2 Tensioner Pads
For a reel lay ship the top tension is generally provided by one or more
tensioners and the tensioner pads squeezing against the pipe are the actual
interface. The tensioner pads can be made from different materials, have
different geometries and have different support shoes and the frictional
coefficient can vary with contact pressure as well as with type and quality of
the pipe coating. Project specific testing is not generally necessary but there is
a considerable bank of test data and FE model results on physical behavior of
different pad designs, Fig. 9, and resulting frictional performance as shown in
Fig. 10.
Fig. 9 FE Model of Tensioner Pad

FrictionCoefficient,

12"PPCoatedPipelineduringInitiation

402mmODPP
365mmODPP

FrictionalSafetyFactor=1.42

TensionerTrackLoading,kn/mpertrack
Fig. 10 Friction Curves

4.3 HFI Welded Pipes

HFI (High Frequency Induction) welded pipes can, in various circumstances, offer benefits over seamless pipe in terms
of reduced lead times, reduced costs, tighter dimensional control, bespoke sizes, good mechanical properties and chemistry
resulting in excellent weldability.
HFI pipe had previously been installed by reeling however due to a lack of historical mechanical integrity data a test
programme was undertaken comprising trials and subsequent material testing on nine pipes with three pipe grades (X52, X60
and X65). After full scale simulated reeling trials a number of mechanical tests were carried out including charpy impact tests
and CTOD tests. All tests were satisfactory (McCann & Rodger, 2009) thus confirming the attraction of HFI pipes for reeled
installation.

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4.4 PE Lined Pipe

Polymer lined pipe has been reel laid on a number of projects. One of the largest such lines was a 16 water injection line
which had a swagelined PE100 liner and Weldlink connectors, (Campbell, 2009).
4.5 Mechanically Lined Pipe
An increasing number of fields have fluid properties which would severly limit the life of carbon steel linepipe material.
For such fields it is possible to use CRA (Corrosion Resistant Alloy) materials such as 13% Chrome, Duplex, Super Duplex,
metallurgically clad pipes, or mechanically lined pipes such as BuBi pipe. Mechanically lined pipes are attractive because the
line pipe costs are significantly lower than metallurgically clad pipes.
A number of such lines have been installed by S lay and approximately 100kms included in nine pipeline bundles (a
recent bundle project is described by Leggett & Simons, 2009). In order to extend the use of these pipes a programme of
reeling trials and mechanical testing has been undertaken to address the main concerns of the maintenance of material
properties during reeling and potential wrinkling of the liner.
The test pipe was 273mm OD, 18.9mm wall thickness, X65 Pipe with a 3mm Alloy 825 liner with approximately 50mm
long weld overlay at the end, see Fig. 10. After reeling simulation extensive testing showed no degradation of the material
properties even after wrinkling of the liner. In addition an FE model was produced which accurately predicts the overall
performance. Further details are given in Mair et al, 2010.
In further work it was established that reeling under a low internal pressure of around 25 bar prevented the formation of
any wrinkles thus maintaining perfect pipe characteristics, see Fig. 11. A detailed operational procedure has been developed
to reliably maintain the internal pressure during the spooling on and offshore pipelay operations, utilizing sealing plugs as
used previously on certain riser installation activities.

Carbon Steel
Outer Pipe

Weld Cladding Typically

Inconel 625

50mm
Nominal
3mm liner

Fig. 10 Schematic of BuBi pipe

Fig. 11 Perfect pipe after reeling

with low internal pressure

Fig. 12 Fatigue Tests

In an extension to this work to allow BuBi pipe to be used for reel-layed risers some preliminary fatigue testing has been
conducted on samples of the pipe after reeling; see Fig. 12. Two tests have been conducted to date with both samples
reaching 20 million cycles. These tests will be run to destruction and further full scale fatigue testing will be carried out in
2010.

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4.6 Reeled Clad Flowlines and DEH

Clad flowlines are currently being installed by the Reel lay method. One such project includes 35km of 12 and 10
diameter clad production flowlines and 7km of 10 diameter carbon steel gas injection flowlines. In addition a Direct
Electrical Heating (DEH) cable will be attached to one of the flowlines (which is part of the above), see Fig. 13. The weld
procedure is a development of that used on BC10.

Fig. 13 DEH Cable Installation by Skandi Navica

4.7 Clad SCRs

A number of SCRs have been installed by reeling as described in Sections 3. One refinement
of SCRs is to use weight optimized design (Karunakaran, 2005) and another is to use lazy wave
SCRs as on BC10 as described in Section 3.4.
There has been considerable work done on improving the fatigue life (eg Atkins et al, 2006,
Lillig et al, 2005, Darcis et al, 2009 and Kan et al, 2009).
It is increasingly becoming required to use Clad pipe for SCRs particularly in the highly fatigue
sensitive areas around the touch-down point and at the critical top sections because H2S is reported
to degrade the fatigue properties of C-Mn steel by a factor of 10-20 in life while clad pipes are
reported to have a performance close to or as good as in air. Considerable work has been done on
this; for example Kristoffersen et al, 2008 concludes that hammer peening of the OD gave a
significant fatigue improvement and also, most importantly for reeled installation, that no effect
from previous reeling of the hammer-peened specimens was observed. This, however, is not
universally accepted and some Operators are currently requiring that clad sections in an SCR
Fig. 14: Welding in Progress
should be J Layed.
Two parallel projects are therefore being undertaken to develop
suitable weld procedures and then conduct full-scale fatigue testing.
The objective is to qualify a reeled Clad SCR. The clad pipe being
used is X65, 318mm OD, 25mm w.t, with Alloy 825 Cladding.
Pulsed hot wire automated GTAW was used with an Inconel 625
weld consumable. A narrow closed gap weld conFig.uration was
used with an internal gas purge which produced a very even and
controlled weld root profile, Fig. 14, 15 and 16.
This weld solution has been tested fully in accordance with DNV
OS-F101 with strain age charpy impacts down to -40C.
Fig. 15: Weld Section

Full scale fatigue testing will be conducted in 2010.

Fig. 16: Root Profile

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4.8 J-Lay
Separate work has also been done on J-Lay welding, (Chong et al, 2009) and
a suite of J-Lay equipment installed on Seven Seas, see Fig. 17, which can
potentially be used for those applications for which reeling is not accepted but is
outwith the scope of this paper.
4.9 High Strength Steel
With increasing water depths and increasing occurrence of HP/HT
developments there is an increasing potential benefit in using higher strength
steels particularly for risers. The lower wall thickness can reduce top tension for
the installation contactor, reduce the size of buoys on SLORS and CORS type
risers and reduce the loads on the production vessel. From the reeling point of
view the main issue is ensuring that the pipeline girth weld overmatches the
strength of the parent pipe material.
At present we have qualified weld procedures with girth weld metal yield
strengths of 109ksi (750MPa) with consumables having Nickel contents less than
1% and hardness limits within that required for sour service.
Fig. 17 Seven Seas J Lay Module

4.10 Hybrid Risers

Hybrid risers such as SLORS and Grouped SLORS, see Fig. 18, are an
attractive field development option, Karunakaran et al 2009. The riser pipes
themselves can be readily reeled and vessels such as Seven Oceans, in which the
crane capacity matches the top tension capacity, are ideal vessels to install such
systems.
4.11 Pipe in Pipe; Enhanced Thermal Performance
It is well known and reasonably straightforward to install standard PIP
flowline by the reel-lay method. A logical evolution of the current technology is
to enhance the thermal performance as far as practicable. This is being done in a
number of phases.
In the first phase a PIP design has been developed with ITP using Izoflex
insulation system. This can be used in two different methods.
Fig. 18 Grouped SLOR

a)

to reduce the outer pipe diameter for a specified thermal performance thus reducing material costs, reducing top
tensions and allowing longer lengths on a vessel reel.
b) enhancing thermal performance for the benefit of the client, given specified pipe diameters.
Table 4 gives an example of the former based on an inner pipe OD of 236mm and U=0.6W/mK
OD
318 mm
367 mm
496 mm

Insulation
Izoflex
Aerogels
P U Foam

Table 4
Insulation
Aerogel
Izoflex

U
1.3W/mK
0.56W/mK

Cool Down
30 hours to 35C
95 hours to 35C

Table 5
As an example of the latter, for a nominal 6 x 10 PIP Table 5
clearly shows the very impressive performance of the Izoflex
system.

Fig. 19

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11

Full scale testing has been done both before and after reeling on a 6 x 10 design using a specially constructed thermal
test rig at Herriot Watt University; Fig. 19. The thermal performance was only reduced by 5-10% due to reeling which can
clearly be allowed for in the design process. Bending trials also showed that with the Izoflex material, because of its strength
in compression, centralisers are not required giving a significant further improvement in thermal performance.
Full scale construction trials have also been performed at a spool base to demonstrate that it is entirely practicable to build
stalks with no centralisers.
4.10 Pipe in Pipe; Electrically Heat Traced Flowlines
As a next step in improving thermal performance a number of
trials have been done with electrical trace heating (EHTF), see Fig.
20. Bench tests/bending trials were conducted which confirmed FE
model results and demonstrated that the mechanical integrity of the
wires was unaffected by the reeling process.
It should be noted that because of the continuous wires in the PIP
annulus this technology can only realistically be laid by the reel-lay
method or in towed bundles.
Electrical heating systems have been used elsewhere and several
projects have been installed with DEH (Direct Electrical Heating)
cables. However the EHTF technology combined with Izoflex
performance only requires approximately one tenth of the power of a
DEH system which is a considerable advantage. It is also suitable
for long step-out distances.

Fig. 20 EHTF Tests.

Typical ETHF power levels are in the order of 10W/m for hydrate mitigation. The ETHF is also useful for producing waxy
oils, with high wax appearance temperatures, because heat can be applied continuously over all, or a significant part, of the
project lifetime.
5. Conclusions
The reel lay method is a well established way of installing in-field flowlines and risers. This paper demonstrates that the
technology can be extended to provide further cost effective solutions and solutions for ever more challenging fields.
Acknowledgements
The authors would like to thank Subsea 7 for permission to publish this paper. None of it would have been possible
without the help of colleagues at Subsea 7 in preparing the paper and also a whole range of onshore and offshore personnel
who executed the projects as well as Clients, Contractors and Suppliers.

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References
- Anon, 1979, Recent Trends in Offshore Pipelay Equipment, Sea Technology, April 1979.
- Atkins, J.G., Lillig, D.B., Hoyt, D.S., 2006, Extension of Deepwater Riser Fatigue Life through Use of Nickel Based Welding
Consumables, DOT, 2006.
- Bertaso, D., Hutt, G., Wang, J., Tews, P., 2009, Improvement Of Fatigue Life Of SCR and OOL In West Africa, OTC 19192, 2009.
- Campbell, T., 2009, Polymer Liner and Connection Qualification for Use in Subsea Pipelines, OTC 19900, 2009.
- Chong, P.H., Smith, S.N., Rodgers, K J., Smith, M., 2009 Meeting Challenging Steel Catenary Risers (SCR) Fatigue Performance using
Standard 1% Nickel Wire, Floating Structures Conference, Glasgow 2009.
- Clarkson 2006, Construction Vessels of the World Eight Edition, 2006/2007, ISBN 1-902157-70-2.
- Denniel, S., 2009, Optimising Reeled Pipe Design Through Improved Knowledge Of Reeling Mechanics OTC 20043, 2009.
- Darcis, P.P., et al 2009, Fatigue Performance of SMLS SCR Girth Welds Comparison of Prefabrication Type WPS, OMAE 200979811.
- De Soras, D & Cruickshank, J., 2000, Combining Flexible and Rigid Pipelay Functions for Ultra Deepwater Operations, Offshore, May
2000.
- Hensley,S, 2008, Deepwater SCR installation by Reel Lay using Seven Oceans, DOT 2008.
- Hoffman, J., Yun, H., Modi, A., Pearce, R., 2010, Parque das Conchas (BC10) Pipeline, Flowline and Riser System Design, Installation
and Challenges, OTC 20650, 2010.
- Kan, W.C., Mortazari, M., Weir, M.S., 2009, Advances in Riser and Pipeline Technologies, Rio Pipeline 2009.
- Karunakaran, D., Lee, D., Mair, J., 2009, Qualification of the Grouped SLOR Riser System, OTC 1989, 2009.
- Karunakaran, D., Melling, T.S. Kristoffersen, S., & Lund, K.M., 2005, Weight Optimised SCRs for Deepwater Harsh Environments,
OTC 17224, 2005.
- Kopp, F., Perkins, G., Prentice, G., Stevens, D., Production and Inspection Issues for Steel Catenary Riser Welds, OTC 15144, 2003.
- Kristoffersen, S., Haagensen, P.J., Rorvik, G., 2008, Full Scale Fatigue Testing of Enhanced Girth Welds in Clad Pipes for SCRs
Installed by Reeling, OMAE 2008-57309.
- Lillig, D.B., Weir, M.S., Kan, W.C., Hoyt, D.S., 2005, Nickel-Based Alloy Welding for Enhanced Fatigue Performance, DOT, 2005.
- MacGregor, J.R., Smith, S.N., van der Hoek, P., 2009, A Family of Offshore Construction Vessels, Trans RINA, 2009.
- McCann, S., Rodgers, K., 2009, Effects of Reeling on the Properties of HFI Welded Pipes, 16th Scandanavian Oil and Gas, July 2009.
- Mair, J., Rommerskircken, I., Schramm, S., Banse, J., Schuller, T., 2010, Mechanical Lined Pipe Installation by Reel Lay, DOT
2010.
- Purvis, M.K, 1946, Craft and Cable Ships for Operation PLUTO, Trans INA (RINA) Volume 88, 1946.
- Smith, S.N., MacGregor, J.R, 2006, Deepwater Pipelay and Construction Vessel, 2nd World Marine Technology Conference, I Mar
EST, London, 2006.
- Smith, S.N., MacGregor, J.R, Rice, B.G.M, & Currie, N.I., 2009 Developing a Deepwater Construction and Pipelay Fleet, Floating
Structures Conference, Glasgow, 2009.
- Tanscheit, P., Sriskandarajah, T., Xavier, M., Solano, R., Braga, V., OMAE 79636, 2009, PDEG-B Overall Design and Installation
Challenges.