pipeline installation, manufacturing, welding and ndt

1 - Classification: Internal 2011-09-09

Offshore flow- and pipelines,

manufacturing, material selection

installation, welding and NDT

Lars M. Haldorsen Ph.D,

Leader Material Technology

Statoil

Mobile: +47 90091669

E-mail: lamha@statoil.com

Content

• Introduction

• Statoil operated pipelines

• Pipelay techniques

• Steel manufacturing and refining mechanisms

• Corrosion and material selection

• Cathodic protection

• Corrosion coating and insulation

• Corrosion Resistant Alloys (Stainless steels)

• Challenges with stainless steels

• Welding

• Engineering Critical Assessment

• None Destructive Examination

Welding, Materials and Fabrication Department

Pipelines and laying techniques

Pipeline transport system

in North Sea

• Export pipelines to Germany,

Belgium, France and the UK

• High regularity and

great flexibility

• Statoil is technical

operator for 7,000km

of pipeline Nyhamna

Europipe II

Europipe I

Norpipe

Teesside

Åsgard

Haltenpipe

Heidrun

Franpipe

Zeebrugge

Zeepipe I

St Fergus

Vesterled

Statfjord

Kårstø

Kollsnes

Melkøya

Snøhvit

Ormen Lange

Easington

Langeled

Ekofisk

Sleipner

Dunkerque

Kristin

Infield pipelines

Future for Norwegian

oil exploration?

Subsea pipeline installation techniques

• NO plastic deformation of pipeline

− S-lay

− J-lay

• PLASTIC deformation of pipeline

− Reel Lay

• Others

− Flex Lay

− Bundles

S-lay principles

• Diameter: 8 - 40”

• Mainly longitudinal welded pipes,

• Laying speed, 100 -500 m/hr

• Normally long transport lines with large dimensions

• Main actors; Saipem, Acergy, Heerema,

• Welding

− Welding onboard (video)

− Working stations; 10 including FJC

− Welding techniques

• Manual and semi-automatic

J-lay principles

• Key data:

− Diameter: 8 - 30”

− Welding onboard

− Mainly longitudinal welded

− Deformations within elastic

limit of the material

− Laying speed, 50 – 150 m/hr

− Normally short lines (risers)

− Challenges: Top tension

− Main actors; Saipem, Acergy,

Heerema, Subsea 7

Reel-lay principles

• Diameter: 4 -18”

• Mainly seamless pipes, (long. welded for clad

and HFW)

• Accumulated plastic deformation, 10-20%

• Laying speed, 600 – 1000 m/hr

• Reel capacity, 2200 -3500 tonnes (10 -15 km)

• Main actors; Subsea 7 and Technip

• Pipeline fabrication; onshore

(Video)

− Up to 24 working stations

including FJC

− Welding techniques;

• Manual and semi-automatic

Reel-lay fabrication yards

• Fabrication yards

− Norway 2 off

− UK 2 off

− Africa 2 off

− Brazil 2 off

− USA 2 off

• Typical stalk lengths: 900 – 1500m

• Number of working stations 15- 24 off

including field joint coating

• Double jointing 12,2m 24,4m

• Welds per shift (12 hrs) 60 – 150 off (1400 –

3600 m for double joints)

• NDT; Automatic Ultrasonic Testing (AUT),

Visual inspection

Videos

• S-lay – offshore fabrication S-lay welding

• Reel lay – site fabrication Spoolbase welding

Steel manufacturing and material refining

techniques

Steel manufacturing

• Raw material ; Scrap and iron ore (pig iron)

− Scrap content varies from 20 – 90%

• Melted in an electric furnace where 90 % of the alloying elements are supplied.

− Remove most of the impurities (phosphorus and ore leftovers by slag (CaMgO)

• Refining in vacuum or inert atmosphere furnaces

− Final chemistry (alloying)

− De-oxidation ( Si, Al)

− Removal of rest impurities (sulphur by slag optimisation and Argon blow through)

− Spectrographic analysis

• Tapping onto continuous casting furnace

Pictures from Tenaris Dalmine

Casting

• Casting

− Continuous casting

− Ingot casting

Seamless linepipe

• Piercing

• Elongation

• Reducing/stretching

• Cutting to 12-13 m lengths

• Heat treatment

• Straightening

• NDT

Longitudinal welded pipes

• Long welded pipes

− UOE process

− Submerge Arc Welded

− Electric Resistance

welded (ERW)

− High Frequency Induction

welded (HFI

Clad pipes; Manufacturing principles

• Manufactured by different production

techniques:

1. Internal cladding by welding (Proclad,

IODS, etc)

2. Lined clad pipe; Mechanical expanded

CRA pipe in backing pipe (Butting,

Cladtek)

3. Clad pipe; Metallurgical bonded clad to

backing material (JSW, Butting)

- 16 -

Lined mechanical bonding principles

Lined pipe end sealing /Cladding

Up to 2008, not good for AUT and

repair

From 2008, repair and NDT

properties improved

Pros and cons, lined clad pipes

• Less expensive compared to

metallurgically bonded clad

• Good tolerances

• Challenges during NDT (AUT)

− Air gap, mix. off materials, etc

• Not reelable, yet

− Techniques under development

(internal pressure, etc)

• Well suited for S-lay and J-lay

Metallurgical bonded clad pipes

What is clad pipes; Manufacturing principles

What is clad pipes; Manufacturing principals

Manufacturing principles; Nickel layer (adhesion)

• The nickel layer applied between the backing

material and CRA has the following functions:

1. Increases homogeneity and reliability of

bonding (clue).

2. Prevents carbon diffusion from the backing

steel to CRA and Chromium diffusion from

CRA to the Carbon material, which in turn

prevents:

• High hardness at the boundary due to

bainite /martensite formation.

• Reduce sensitivity of boundary cracking.

3. Reduces the risk of cracking under

hydrogen service

4. Reduces the penetration rate of pitting

and/or stress corrosion cracking, if initiated

at the cladding surface

Principals for refining of mechanical properties in steel by heat

treatment

Heat treatment; principles • Quench and tempering

Heat treatment; quenching results

Feritt + perlitt

Refining of mechanical properties in steel,

tempering vs. mech. properties

1000.0

1100.0

1200.0

1300.0

1400.0

1500.0

1600.0

1700.0

1800.0

1900.0

0 200 250 300 350 400 450 500 550

anl.temp. (grader celsius)

Rm (Mpa)

Rp0,2(Mpa)

Charpy V

A5 (%)

Refining of mechanical properties in steel

by quench and tempering

• Austenitisation temp. 920 0C

• Cooling 1.75 0C/sec. in water + 10 % NaOH.

• Tempered at 590-670 0C

Feritt + perlitt

Tempered martensite/ainite

Heat treated steel

Strain

1000 kg

Mild steel

Refining of mechanical properties in steel by

quench and tempering

No permanent

deformation

Permanent deformation

Heat treated steel Mild steel

Linepipe dimensions and ranges W

kness [ Inch]

Outer Diameter (OD) [ Inch]

Corrosion and material selection

Corrosion

• Corrosion is deterioration of essential properties in a material due to reactions with its surroundings. In the most common use of the word, this means a loss of an electron of metals reacting with water and oxygen.

Corrosion

• Corrosion of pipelines is divided into two

categories:

− Internal corrosion

− External corrosion

• Internal corrosion (main categories)

− CO2 corrosion (dominating)

− H2S corrosion

• External corrosion (main categories)

− General corrosion

− Pitting corrosion

− Crevice / Hydrogen induced cracking

Internal corrosion protection

Material selection

• Corrosion Resistant Alloys, CRA(Duplex stål, 13%Cr steel)

− Very good resistance against CO2 corrosion

− Good resistance against H2S corrosion

− Some of the CRA’s are sensitive to contact with

sea water

• C-Mn steel

− Low resistance against CO2 corrosion

• Inhibitors

• Corrosion allowance

• Increase Cr-content

− Acceptable resistance against H2S corrosion

• Internal coating (organic)

− FBE +polymers

• Good corrosion control

• Sensitive to sand production

• Technology in start phase

Fig. from Kawasakis patent increase Cr- in C-Mn Stål

External corrosion protection

Material selection

• CRA materials

− Sensitive to contact with seawater in combination

with Cathodic protection.

• Hydrogen induced cracking, crevice and pitting

corrosion

− Cathodic protection

− Corrosion protection and isolation need to be water

• C-Mn steel

− Good corrosion resistance when protected by:

• Properly applied corrosion coating

• Clad pipes

− Good corrosion resistance when protected by:

• Properly applied corrosion coating

External corrosion protection

Material selection

− Single anodes with equidistance distribution (200-

• Evenly distributed electro- potential

• Difficult to get water tight at the contact point

(Crevice problems)

• Surface protection (coating)

Cathodic Protection (CP)

From Wikipedia:

• Cathodic protection (CP) is a technique to control the corrosion of a metal surface by making that surface the cathode of an electrochemical cell.

• It is a method used to protect metal structures from corrosion. Cathodic protection systems are most commonly used to protect steel, water/petroleum pipelines and storage tanks; steel pier piles, ships, offshore oil platforms and onshore oil well casings.

• A side effect of improperly performed cathodic protection may be production of molecular hydrogen, leading to its absorption in the protected metal and subsequent hydrogen embrittlement

Cathodic protection; Pourbaix diagram

Protection potential for steel in seawater

Potential distribution

Cathodic Protection; Anode specification

• Anodes are typically made of

aluminium (Al-Zn-In material).

• Anodes are typically mounted every

200-300 m along the pipeline.

• Typical anode weight is 30-40kg (10”

pipeline)

Anode types

Stand off Flush mounted Bracelet

Indium and zinc are added to reduce the passivation effect of the oxide

film and to avoid pitting. The electrochemical efficiency (Ah/kg) and the

anode potential (V) are improved with In and Zn alloy

elements.

Coating and insulation

Production chemistry – the problems

How to keep the hydrocarbons hot during

transport?

Insulation

05.10.2012

Why coating? • Corrosion protection

− Reduce amount of anodes by 90%

− Avoid reduction of hydrogen at the steel surface (13%Cr, Duplex)

• Insulation of pipeline

− Avoid formation of hydrates, wax etc (flow assurance)

• Mechanical protection, e.g. trawl impact

What is coated? • Pipeline

− Line pipe

− Field joint

• Spools

− Line pipe

− Field joint

− Bend

Coating types • Fusion Bonded Epoxy (FBE)

• Polypropylene (PP) Crystallin thermo plastic

• Polyurethane (PU) Thermoset plastic

• Pipe in pipe (Typical PU)

• Polyethylene (PE) Crystallin thermo plastic

• Polychloroprene (neoprene rubber)

3 layer Polypropylene (3LPP)

Multi-layer Polypropylene

Coating qualification tests • Bend test

• Impact resistance

• Cathodic disbondment

• Hardness

• Adhesion

• Abrasion

• Heat transfere test

• Ageing test

• Shear strength test

• Fungal & Bacterial Growth test

• UV test

Qualification of coating - Bending test

Field Joint coating

• Polypropylene field joint coating is produced in

accordance with the principles of 3LLP system:

1. FBE

2. PP Adhesive

3. Injection moulded PP

Welding and Non Destructive Examination

Content

• Welding

− Definition of welding

− Pipeline Welding Techniques

− Welding Procedure qualification

− Testing

− Documentation, Welding procedure Specifications

• None Destructive Examination

− Examination methods

Origin of Electrical Arc Welding

In 1885, Nikolai Benardos and Stanislav

Olszewski were granted a patent for an

electric arc welder with a carbon electrode

called the Electrogefest. Nikolai Benardos

(Russia) and Stanislav Olszewski (Poland)

are considered the inventors of modern

welding apparatus.

Effects of Welding

• Fusion Zone

− Mixture of welding consumable and molten

origin metal

• Welding consumable is made for the

purpose and ends up with good properties

• The fusion line ends up with material

properties resulting from the mixture and

these have to be evaluated carefully

(Schaeffler)

• Heat-affected zone (HAZ) is the area of base

material which has had its microstructure and

properties altered by welding

− (1) weld metal, (2) fusion zone

− (I) overheated section, grain growth (II) grain-

refined (normalized) section, (III) partially grain-

refined section, (IV) recrystallized section, (V)

aging section

Arc welding processes

Arc welding

12 Submerged Arc Welding (SAW)

111 Metal-arc welding with covered electrode (SMAW) 114 Flux cored wire metal-arc welding (FCAW) 131 MIG welding: metal-arc inert gas welding (GMAWi) 135 MAG welding: metal-arc active gas welding (GMAWa) 136 Flux-cored wire metal-arc welding with active gas shield (G-FCAW)

141 TIG welding: tungsten inert gas arc welding (GTAW)

Shield Metal Arc Welding; SMAW

• Shield tasks

− Protection gas (CO2, CO, H2)

− Protection slag (cooling and

oxidation)

− Alloying elements

− Arc stabilising

− Utilisation (120%)

SMAW welding of pipelines

Submerged Arc welding; SAW

Gas Metal Arc Welding; GMAW; MIG/MAG

Gasses:

• Metal inert gas, MIG welding

• MIG welding uses an inert gas (Argon and /or Helium). For this process the gas do not actively react with the welding process. The purpose of the gas is to protect the liquid smelt for reactions with the surrounding environment

• Metal Active Gas, MAG

• MAG uses an active gas (CO2, Hydrogen Argon and mixture of these), meaning that the gas react with the smelt and contribute to the heating process. In addition the gas protect the smelt from the surrounding environment

• Welding consumable

− Solid metal electrode Ø 0,6 – 2,4mm

Gas Tungsten Arc Welding, principle

Flux Cored Arc Welding; FCAW

Flux Cored Arc Welding; FCAW, cont.

Welding positions

Welding Position Test Position ISO and EN

Flat 1G PA

Horizontal 2G PC

Vertical Upwards Progression 3G PF

Vertical Downwards Progression 3G PG

Overhead 4G PE

Pipe Fixed Horizontal 5G PF

Pipe Fixed @ 45 degrees Upwards 6G HL045

Pipe Fixed @ 45 degrees Downwards 6G JL045

Bevelling

I-bevel V-bevel X-bevel

J-bevel

Perform welding

Record Parameters

Parameter record

Material cert.

Consumable cert.

Perform Mechanical

testing of as-welded

Perform Mechanical

testing of Strain-

Non Destructive

Testing

NDE Reports

Mechanical

Properties

Mechanical

Properties

ECA Report

NDE Accept

Criteria WPQR

Welding procedure qualification

Welding Procedure

Specification

Fabrication Challenges

• Different weld types and location:

o Mainline girth weld

o Tie-in girth weld

o Repair welds

o Seal weld/weld overlay.

• Defect locations:

• Defect detection and interaction.

Fabrication Aspects

• Weld indications and defects from typical project pipe

• Weld defect locations from typical project pipe

Fabrication Aspects

None Destructive Testing

NDT- Non-Destructive Testing • Definition of NDT

• Overview of methods relevant to pipelines

• AUT

The use of noninvasive

techniques to determine

the integrity of a material,

component or structure

quantitatively measure

some characteristic of

an object.

i.e. Inspect or measure without doing harm.

Definition of NDT

Methods of NDT

Visual

Five Most Common NDT Methods

• Visual

• Liquid Penetrant

• Magnetic

• Ultrasonic

• X-ray

Most basic and common

inspection method.

Tools include fiberscopes,

borescopes, magnifying

glasses and mirrors.

Visual Inspection

Liquid Penetrant Inspection

• A liquid with high surface wetting

characteristics is applied

• The excess liquid is removed

• A developer (powder) is applied.

• Visual inspection.

Liquid Penetrant Inspection

Magnetic Particle Inspection

• Magnetic Ink applied.

• The part is magnetized

Magnetic Particle flux

• Flux leakage is formed

Magnetic Particle inspection

Radiography

The radiation used in radiography testing is a higher energy (shorter wavelength) version of the electromagnetic waves that we see as visible light. The radiation can come from an X-ray generator or a radioactive source.

High Electrical Potential

Electrons - +

Exposure Recording Device

Radiation

Penetrate

the Sample

Cluster porosity

Film Radiography

Cracks.

Film Radiography

Lack of Penetration

Ultrasonic inspection

Ultrasonic wave forms

Longitudinal wave

Shear wave

Surface wave

High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws. Reflected sound energy is displayed versus time, and inspector can visualize a cross section of the specimen showing the depth of features that reflect sound.

0 2 4 6 8 10

initial

back surface

Scanning

angle beam

Ultrasonic Inspection

• Size Evaluation

AUT- Automatic Ultrasound Inspection

AUT- Automated Ultrasonic Inspection

TOFD -Time of Flight Differaction

• Not amplitude base method

• Diffracted signals

• Matched angle probes

• Longitudinal wave

• PE-Pulse Echo

• Weld is divided into zones

• Each zone is scanned separately

• TOFD and PE

pipeline installation, manufacturing, welding and ndt

lay bundles

reellay principles diameter

slay principles diameter

fjc welding techniques

material laying speed

jlay principles key

fabrication department

pipeline nyhamna europipe

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