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Challenges of Installing El t i ll H t d Li d PiElectrically Heated Lined Pipe

Wacek Lipski

seabed-to-surface

4th June 2008

Contents

Who are Acergy

hTyrihans project overview

Key installation challenges

Acergy Piper overview

Integration of Cable Lay spread

Welding of Bubi Pipe

NDT of Bubi Pipe

Cable Strapping

Summaryy

seabed-to-surfaceprivate and confidential06 June 2008slide 2

Who are Acergy?

We are a seabed-to-surface engineering and construction contractor for the offshore oil and gas industry contractor for the offshore oil and gas industry worldwide. We plan, design and deliver complex, integrated projects in harsh and challenging offshore environmentsenvironments.

Our Vision:Acergy’s vision is to be the acknowledged leader in seabed to surface engineering and constructionseabed-to-surface engineering and construction.


Tyrihans Project Overview


Kristin A Åsgard BAcergy Falcon Scandi Acergy

Acergy Piper


Tyrihans Project Overview

Acergy 2007 Scope:Installation of 16/18” Production pipeline from Kristin to p pTyrihans South, complete with piggy backed Direct Electrical Heating (DEH) cableInstallation of 10” Gas Injection line from Åsgard to Tyrihans Installation of 10 Gas Injection line from Åsgard to Tyrihans South

Challenges imposed by the field:Product from Tyrihans field and possible future tie-in’s required either complete CRA or CRA lined production pipeHydrate control evaluated to be most economical using an Hydrate control evaluated to be most economical using an electrical heating systemLongest/largest diameter pipeline installed with DEH systemDue to long, previously untried cable length, risks of spark-over which is difficult to detect. Requires high quality cable installation


sta at o

Tyrihans Project Overview – System Components


16/18” Production Pipeline Specifications

43 km total length – 0.4 km 16”->28.3 km 18” ->14 km 16”23 9 WT DNV GR 450 SAWL IFD ith 3 316 L 23.9 mm WT, DNV GR 450 SAWL IFD with 3 mm 316 L mechanically bonded liner43 km of DEH cable, 15.5 kg/m, 85 mm OD, 700 tonnes in , g/ , ,total500 m of AFC cable, 52 kg/m, 135 mm OD, temporarily strapped to the pipestrapped to the pipe700 Tonnes of MPSWater depth 320 mpSoft silty clays15 curves, radius 2000 m


Contents

Who are Acergy






NDT of Bubi Pipe

Cable Strapping

Summaryy


Key Installation ChallengesD i i t ll ti d i t ti f b d bl l Design, installation and integration of brand new cable lay spread onto Acergy PiperWelding and NDT of mechanically bonded lined pipeg y p pDesign and qualification of strapping system to hold heating cable onto the pipelineM i t i i t ti t l th ti tMaintaining a rotation tolerance over the entire route


Key Installation ChallengesAlsoAlso...

Initiation with anchored barge in a congested seabedCurve layabilityy ySystem Behaviour (interaction effects)PP injection SystemMPS/Cable handling

Fundamental factor in solving these is a large, robust working platform….Acergy Piperplatform….Acergy Piper


Contents

Who are Acergy






NDT of Bubi Pipe

Cable Strapping

Summaryy


Acergy Piper - Overviewd3rd generation, anchor positioned lay barge

One of the most efficient semi-submersible pipelay bargesbarges

Outstanding track record of achievement in the challenging environmental conditions of the UK and Norwegian sectors of the North Sea

Also successfully carried out significant pipe lay and trunkline operations in West Africa the Mediterranean trunkline operations in West Africa, the Mediterranean and the Gulf of Mexico

Renowned for high speed lay of large diameter, concrete e o ed o g speed ay o a ge d a ete , co c etecoated, carbon steel pipe, but now also a world leader in specialised complex pipeline installation.


Acergy Piper - Specifications

340 tonne top tension capacity53,500 Tonnes displacement at 20 m working draft, p gDimensions: 167.5 m x 58.5 m x 33.2 mAccommodation for 400+ personnel2000 Tonne pipe storage capacity14 point mooring systemWater depths up to 450 m + depending on pipe Water depths up to 450 m + depending on pipe characteristics8 main line work stations plus double jointing stationsUsually supported by 3 anchor handlers & supply boatsExcellent lay accuracySt bl l tf bl t t ti l ti d Stable platform, able to operate continue lay operations and maintain position in harsh conditions


Acergy Piper – The Challenge

The challenge was to The challenge was to convert Piper from a ‘high speed’ carbon steel pipe l b t l ti l lay barge to a relatively low speed, high quality production base for a relatively short piggybacked pipelineThis required many This required many physical changes, but also cultural changes onboardonboard


Contents

Who are Acergy






NDT of Bubi Pipe

Cable Strapping

Summaryy


Integration of Cable Lay Spread – The Challenge

Up to now, Acergy Piper had only been used for lay of generally long and relatively large concrete coated pipesgenerally long and relatively large concrete coated pipesPiper had never before installed a piggy backed cable so a new customised system had to be developed to suit the specific needs of the projectFundamental system requirements were:

DEH cable stored on board in one lengthDEH cable stored on board in one lengthTemporary system to install a second cable (Armoured feeder cable) for the first 450 m of layDue to the weight of the cable (700 tonne +) payout of pipe needed to be de-coupled from movement of cable storage unitstorage unitStore/handle/install 700 tonnes of MPS


Integration of Cable Lay Spread – The Solution

AFC Reel

Cable Repair Shack Location

Accumulator

Spooling Tower

Carousel

Spooling Tower

Carousel

Cable Touchdown on Pipe


Integration of Cable Lay Spread – The Solution

DEH Cable

Cable Tensioners

AFC AFC Cable


Integration of Cable Lay Spread – In Action


Contents

Who are Acergy






NDT of Bubi Pipe

Cable Strapping

Summaryy


Welding of BuBi Pipe – What is Bubi?

Trade name for Buttings Bi-Metal PipeMechanically bonded pipe fabricated by expanding a 316L liner inside a carbon steel parent pipeliner inside a carbon steel parent pipeSeal welded at ends to prevent contamination and moisture ingress between the liner and parent pipe


Welding of BuBi Pipe – The Challenge

Acceptance Criteria – allowable defect size less than 1 mm in Root and Hot passContamination prevention no contact Contamination prevention – no contact between CRA liner and carbon steelWelding speed to achieve required qualityConsequences of a cut-out – Cold cut required and seal weld must be reinstatedCold cutting is slow and seal weld is manual so Cold cutting is slow and seal weld is manual so very time consumingChallenge is to define a welding process and material that is very reliable but not overly slow


Welding of BuBi Pipe - The Solution

Undertook extensive trials of a large number of welding processes and fill materials

d b l dGTAW proved to be extremely sensitive to pipe geometry and thus not suited to this project given the pipe manufacturing and bevel tolerancesGMAW with Duplex resulted in generally higher than permissible porosityTherefore final process utilised GMAW with Inconel for the Therefore, final process utilised GMAW, with Inconel for the Root and hot pass and Incoweld 686 for the fillIncoweld 686 for the fill gave superior strength to 625


Welding of BuBi Pipe - The Result

Final result was a very low repair rate and no welding cut-outs out of over 1700 offshore welds out of over 1700 offshore welds

3mm

Root pass

Hot pass

Circa 8mm


Contents

Who are Acergy






NDT of Bubi Pipe

Cable Strapping

Summaryy


NDT of BuBi Pipe – AUT vs Radiography

What prevents AUT being used on lined pipe?No bonding between liner and pipe body prevent through g p p y p gsound transmissionSeal weld on pipe bevel Control of welding parameters for seal weld vertical height Control of welding parameters for seal weld vertical height after bevellingNo control over depth of penetration of seal weld

Problem Area

?


NDT of BuBi Pipe – Weld Metal

Difficulties with weld metal:Ferritic materials are fine grained and are well inspected g pby ultrasonic techniquesAustenitic materials with a course grained structure are more difficult to inspect with ultrasonicsmore difficult to inspect with ultrasonics

Austenitic weldAustenitic weldAustenitic weldAustenitic weld

100% Carbon steel100% Carbon steel

Carbon steelCarbon steel


NDT of BuBi Pipe – The Challenge with Radiography

Therefore, Inspection by Radiography is the only practical way forward.Main issues with traditional radiography are:

Slow process due to development timeRequirement for dark rooms on board chemicals etc Requirement for dark rooms on board, chemicals etc –safety/space issues

Regardless of radiographic method used, difficult to prove at g gwhat depth the defect is so can’t have different criteria on the same x-ray passGiven we had different criteria between root and hotpass and Given we had different criteria between root and hotpass and fill, only way to deliver a quality product was to x-ray at two different stationsAf i ifi h R l i R di h (RTR) After significant research, Real time Radiography (RTR) was selected as the NDT method for Tyrihans


NDT of BuBi Pipe – The Solution

WS 1 -Root and Hot Pass

WS 1.5 –intermediate X ray

WS 2 & 3 Fill and Cap

WS 4 Final X-ray

Hot PassX-ray

Battery Powered X-Ray Crawlers


NDT of BuBi Pipe – The Result

The RTR system is capable of replacing conventional offshore film inspection at standards that equal or exceed filmstandards that equal or exceed film

No development timeNo chemicals or separate dark room requiredrequired

2 Digital detectors diametrically opposite scan the pipe, during x-ray exposure by i t l linternal crawlerDeployed after the hot pass (WS. 1 ½) and after completion of weld (WS. 4)

Repairs at Station 1 ½ require less time that full weld repair Root and Hot pass criteria would have pbeen applicable to full weld if only scanning at WS. 4


Contents

Who are Acergy






NDT of Bubi Pipe

Cable Strapping

Summaryy


DEH Cable Strapping System – The Problem

System design required the DEH cable and MPS to be cable and MPS to be permanently strapped to the pipe Previous pipeline systems of this type had been installed with reel/J-lay such that straps did / y pnot have to pass over multiple stern ramp rollersProject required over 50 000 Project required over 50,000 individual straps to be installed


DEH Cable Strapping System – The Analysis

Extensive analysis was undertaken into strapping system and installation loads to determine performance and installation loads to determine performance requirements

Analysis included Analysis included consideration of:

Roller contact loadsI t ti b t MPS Interaction between MPS sections, straps, coatingInfluence of strapping i hil i b d pipe while in an overbend

configurationBehaviour of cable under compression inside the MPS


DEH Cable Strapping System – The Solution

After extensive market research it was determined that off the shelf products were unsuitable or unavailable and a custom designed and fabricated solution was requiredAcergy entered into an agreement with a subcontractor for design and delivery of a suitable solutiondesign and delivery of a suitable solutionFinal product – Weblock buckle with Vectran webbing material


DEH Cable Strapping System - Weblock

Duplex Buckle:Custom designed and fabricatedD i ti i d t i i t th d i i i Design optimised to maximise strength and minimise fabrication costs - All duplex components stamped and folded from flat sheetBuckle ultimate strength in excess of 3 tonnes – still room for optimisation in the future


DEH Cable Strapping System – Vectran

Vectran webbing:Liquid Crystal Polymer fibre, typically used for fishing, military or aerospace industry custom woven for this military or aerospace industry, custom woven for this applicationStronger weight to strength ratio than Inconel & Virtually

i f li i t tzero creep – marine fouling resistantExcellent wear and abrasion resistanceVirtually impervious to damage while passing over stern y p g p gramp rollers


Contents

Who are Acergy

Tyrihans project overviewTyrihans project overview


Acergy Piper overviewAcergy Piper overview


Welding of Bubi PipeWelding of Bubi Pipe

NDT of Bubi Pipe

Cable StrappingCable Strapping

Rotation Control

SummarySummary


Rotation Prediction and Control – The ProblemContinuous Rotation tolerance specified along the pipeline due to DEH Cable performance and in-line structures - +/- 60 degrees along entire route, +/- 15 deg at in-line structures.

Typical effects usually considered to have an influence on rotation:rotation:

Rotation due to plastic strain (Endal effect)Tensioners Seabed unevennessCurrentsCurvesCurvesAsymmetric Bundle Stiffness

Only these can be quantified


Rotation Prediction and Control – The Analysis

Endal Effect (plastic strain) was identified as the biggest single contributor to rotationRotation due to asymmetric bundle bending was also identified Rotation due to asymmetric bundle bending was also identified as significant based on extensive analysisRotation due to curves was predicted

100

12016 in, MPS 45 deg

Rectangular Beam, 10%Stif fness Dif ference16 in, MPS 22.5 deg

60

80

Torq

ue (N

*m/m

)

16 in, AFC 10 deg

Design Torque

Minimum Sagbend Radius

0

20

40

0 200 400 600 800 1000 1200 1400

T

0 200 400 600 800 1000 1200 1400

Bend Radius (m)


Rotation Prediction and Control – The Solution

Plastic Strain induced rotation would have been unmanageable offshore, therefore a ‘flat’ stern ramp setup was adopted.Potential rotation due to asymmetric bundle bending was Potential rotation due to asymmetric bundle bending was mitigated using buoyancy modules, complete with novel torque transfer system


Rotation Prediction and Control – The Result

Extensive rotation measurements taken by ROV during layWhere trends were identified along the route, corrective measures were taken in terms of cable repositioning or measures were taken in terms of cable repositioning or Buoyancy module installation.Rotation behaviour was well within predicted parameters and

ti i li i t ll d ll ithi ifi tientire pipeline was installed well within specifications.


SummaryWe successfully installed the Tyrihans production pipeline without a single weather laydown, proving that Acergy Piper

y

is a unique and versatile lay bargeWe took on board 700 tonnes + of cable in one piece Successful development and integration of a cable lay system Successful development and integration of a cable lay system onto the Acergy PiperZero welding cut-outsHighly successful RTR NDT system incorporated on-boardDeveloped and successfully used new strapping systemMaintained required rotation tolerances over the entire routeMaintained required rotation tolerances over the entire routeIn Future, we can consider installing similar pipelines with longer/larges of cable in a single length


Thanks for Listening…Any Questions?g y Q


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