FINAL Subsea Pipeline Cluster Report 56pp

8/9/2019 FINAL Subsea Pipeline Cluster Report 56pp

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Advancing our knowledge of subsea pipeline technologyto support the oil and gas industry

Subsea PipelinesCollaboration Cluster

Final report

WEALTH FROM OCEANSwww.csiro.au


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Executive summary

Introduction to the

Subsea Pipelines Cluster

Training the offshore

pipeline engineers

of the future

Scientific and

engineering challenges

Scientific outcomes

of the Flagship

Collaborative Cluster

Putting the Cluster’s

research into practice

Commissioningexperimental equipment

for ongoing pipeline

testing in Australia

Publications and

dissemination

Key papers

Awards

Keynote presentations,

invited lectures and papers

Hosting international

conference ISFOG

The Partners

Flagship Collaboration

fund


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Subsea Pipeline Collaboration Cluster – final report

Executive summary

Offshore subsea pipelines are used to export oil and gas from the field to platform andthen from the platform to the mainland. As they are the sole conduit for the hydrocarbons

their stability and integrity are of critical economic and environmental importance.

More than per cent of Australia’s

gas resources exist in deep, remote,

offshore areas and being able to realise

the full potential of these remote

resources relies on the development

of economically viable transportation

solutions. Technical solutions for

Australia’s offshore pipelines must

maintain structural integrity and

continuous supply of products across

hundreds of kilometres of seabed.

Such technology is also vital to Australia

achieving the vision of “platform

free fields”, a CSIRO Wealth from

Oceans Flagship initiative. Platform

free fields research investigates ways

to replace traditional oil and gas

platforms with subsea technologies

for production of gas resources which

may lie as far as km offshore,

at a depth greater than km.

To address the challenges of providing

technical solutions to the Australian

oil and gas industry, six universities

and CSIRO’s Wealth from Ocean

Flagship came together in

to establish the Subsea Pipelines

Collaboration Cluster. Its goal was to

underpin the development of these

hydrocarbon resources, by providing

engineering solutions for the safe

and economic design and operation

of subsea pipelines in Australia’s

offshore frontiers. This research

Cluster was enabled by a . million

grant through the CSIRO Flagship

Collaboration Fund and in-kind

contributions from the participating

universities of . million. Bringing

together an integrated and multi-

disciplinary team has been fundamental

to the success of the Cluster.

The Cluster has resulted in significant

advances in the understanding

of subsea pipeline technology,


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including the development of state-

of-the-art experimental equipment

to test pipeline attributes.

Key achievements include establishing

new numerical models and software

for analysing the stability of offshore

pipelines, novel methodologies for

economic and safe pipeline design,and the commissioning of world-

class experimental and pipeline

testing facilities. These have resulted

in specialist testing and consultancy

services being available to the offshore

pipeline industry. The increased

knowledge and understanding will

contribute to CSIRO’s own research

in the areas of gas flow assurance

and production. They are also

publically available with the Cluster

having published more than

manuscripts in international journal

and conference proceedings.

Results from the Cluster’s research has

already been incorporated into the

next generation of subsea natural gas

projects such as the A billion Gorgon

project in north-west Western Australia

that involves the development of the

Greater Gorgon gas fields and a LNG

plant on Barrow Island, near Karratha.

Acting for clients BP, Chevron, Inpex and

Woodside, testing facilities developed

have also underpinned designs for

Australia’s future pipelines to the Pluto,

Wheatstone, Ichthys and Browse fields

(off the north-west Western Australian

coast) and in international projects

offshore West Africa, Egypt and in the

Caspian sea. Research in the cluster also

formed part of a joint industry project

sponsored by the six energy majors

BHP Billiton Petroleum, BP, Chevron,

Petrobras, Shell and Woodside, and

administered by the Minerals and

Energy Research Institute of Western

Australia (MERIWA Project M).

The current boom in Australian oil

and gas has caused a skills shortage in

key engineering fields. It is therefore

a key achievement that this cluster

has also trained offshore engineers

and researchers for the benefit of

the offshore oil and gas industry

through its PhD and postdoctoral

programs. This will help underpin

the future success of engineering

in this area of national priority.

The Cluster outcomes are helping to

build future research priorities in CSIRO,

the Universities and with industry

partners in the areas of pipeline design

and installation in Australian calcareous

soil conditions and in deep water,

geohazard risk assessment, use of

automated underwater vehicles and in

developing the vision of platform free

fields in Australia. Future activities, such

as interactive workshops, will build on

this successful collaborative relationship.

This report summarises the

achievements of the Subsea

Pipeline Collaboration Cluster and

its impact on the Australian and

international oil and gas industries.

Past CSIRO Wealth of Oceans Flagship Director Kate Wilson (right), CSIRO Energy ExecutiveBev Ronalds (centre) and UWA Vice Chancellor Alan Robson (left) at the Cluster launch

Mark Cassidy

Leader

CSIRO Flagship CollaborationCluster on Subsea Pipelines

The University of Western Australia

Ian Cresswell

Acting Director

CSIRO Wealth fromOceans Flagship


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Introduction to the Subsea Pipelines Cluster

Building a pipeline system to link an offshore oil and gas field to the mainland

represents a huge capital investment. For example, in Australia the construction of the

inch km pipeline for the Trunkline System Expansion Project (TSEP) on the North

West Shelf in / cost approximately A million. Today, the cost per kilometre

of current pipeline projects, including the Gorgon (water depth: m length:

and km), Scarborough (depth: m length: km), Pluto (depth: m length:

km) and Browse (depth: m length: , and km) is estimated to exceed

. million per kilometre. With over km of pipelines under design in Australia,

capital expenditure is expected to exceed billion.With more than per cent of

Australia’s gas resources exist in deep,

remote, offshore areas, our ability

to realise their full potential relies

on the development of economically

viable solutions to transport them.

Such technology is vital to Australia

achieving the vision of Platform Free

Fields, a CSIRO Wealth from Oceans

Flagship program. This research

investigates ways to replace tradit ional

oil and gas platforms with subseatechnologies for production of gas

resources which are considered

stranded off our coast in deep water

and at long distances to land. Under

these conditions subsea pipelines are

required to transport the gas over

long distances to shore. Transporting

hydrocarbons in extra long offshore

pipelines poses many challenges that

must be considered when designing

pipelines. These include stability of

pipeline structures over decades in

strong currents, a shifting seabed andon steep seabed slopes. Assessment

and mitigation of potential geohazards,

such as submarine landslides, is also

critical for the safe routing of pipelines.

The Subsea Pipelines Collaboration

Cluster was established to meet

these challenges and to deliver

science-based engineering solutions

for the safe and economic design

and operation of subsea pipelines

in Australia’s deepwater frontiers.

Research has focused on ultralong

pipelines from deepwater to shore, a

critical goal of Platform Free Fields.

The CSIRO Flagship Collaboration

Fund enables the skills of the wider

Australian research community to

be applied to the major national

challenges targeted by CSIRO’s National

Research Flagship Program. As part of

the million provided over seven

years by the Australian Government

to the National Research Flagships,

million was allocated specifically

to enhance collaboration between

CSIRO, Australian universities and other

publicly funded research agencies.

The Subsea Pipeline Collaboration

Cluster was initiated by the Wealth

from Oceans Flagship to bring

together a diverse range of research

capabilities to deliver an in-depth

scientific understanding of the

key parameters involved in subsea

pipeline design, construction, long-

term operation and monitoring.

The three year program contributed

to CSIRO’s research program that aims

to work with industry to develop the

science and technology to unlock new

opportunities in the exploration and

development of Australia’s offshore

hydrocarbon resources. The .

million Cluster included . million

from the Flagship Collaboration Fund

and . million in-kind contributions

from the participating universities.

The Subsea Pipeline Collaboration

Cluster combined the research

capabilities of The University of

Western Australia, Curt in University

of Technology, The University of

Queensland, Monash University, The

University of Sydney, Flinders University

and CSIRO through the Wealth from

Oceans National Research Flagship.

From a start of Chief Investigators the

cluster grew to eventually encompass

academic researchers and another

PhD and Masters students.


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CSIRO Cluster on Subsea Pipelines Participants

SEABEDCHARACTERISATION

Lead Researcher

Professor Mark Randolph

Researchers

Professor Liang Cheng

Professor David White

Professor Mark CassidyDr Itai Einav

Dr Pierre Rognon

Dr Noel Boylan

Dr Hongxia Zhu

PhD Students

Han Eng Low

Zhihui Ye

Yan Yue

Hamed Mahmoodzadeh

Poornaki

STRUCTURALINTEGRITY

Lead Researcher

Professor Mark Cassidy

Researchers

Professor Xiao-Ling Zhao

Professor Jayantha Kodikara

Dr Faris Albermani

Dr Yinghui Tian

Professor Mark Randolph


Dr HongBo LiuDr Zhigang Xiao (until )

Dr Pathmanathan Rajeev

PhD Students

Mehdi Golbahar

Matthew Hodder

Bassem Youssef

Senthilkumar Muthukrishnan

Hossein Khalilpasha

SEABED MORPHOLOGY

Lead Researcher


Researchers

Dr Ming Zhao

Dr Zhipeng Zang

PhD Students

Di WuSiti Fatin Mohd Razali

Fang Zhou (Visitor)

Xiaosong Zhu (Visitor)

PIPELINE HAZARDS

Lead Researcher


Researchers


Professor Mark RandolphAssociate Professor Yuxia Hu

Dr Tom Baldock

Dr Christophe Gaudin

Dr Nathalie Boukpeti

Dr Dong Wang

Dr Noel Boylan

PhD Students

Jaya Kumar Seelam

Hee Min

Indranil Guha

Fauzan Sahdi

PIPELINE RELIABILITY

Lead Researcher

Professor Hong Hao

Researcher

Professor Mark Cassidy

Dr Ying Wang

PhD Students

Xuelin PengChunxiao Bao

Wang Chao (Visitor)

AUV AND ROV-BASEDSYSTEMS FOR PIPELINEMONITORING

Lead Researcher

Associate Professor

Karl Sammut

Researchers

Associate Professor Fangpo He

Dr Jimmy Li

Dr Kim Klaka

Dr Alec Duncan

Mr Andrew Woods

PhD Students

Andrew Lammas

Matthew Kokegei

David Robert

Tae-hwan Joung

Lyndon Whaite

Grant Pusey


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Training the offshore pipeline

engineers o the ftureThe Subsea Pipeline Collaboration Cluster is not only devising tomorrow’s subsea pipeline

technology, it is providing significant research training for Australia’s future pipeline engineers.

In all, PhD students and research associates undertook pipeline research within the cluster.


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Chief Investigators

Jayantha Kodikara

Xiao-Ling Zhao

Itai Einav Faris Albermani

Tom Baldock

Jimmy Li

Kim Klaka

Alec Duncan

Andrew Woods

Mark Cassidy

The University of Western Australia The Universityof Sydney

FlindersUniversity

Curtin Universityof Technology

MonashUniversity

The Universityof Queensland

Mark Randolph Liang Cheng

David White

Hong Hao

Karl Sammut

Christophe Gaudin

Fangpo He


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CSIRO Cluster Postdoctoral Research Associates

NAME INSTITUTION PROJECT WHERE THEY ARE NOW?

Hongjie Zhou University of Western Australia Seabed Characterisation Advanced Geomechanics

Pierre Rognon University of Sydney Seabed Characterisation University of Sydney

Noel Boylan University of Western Australia Seabed Characterisation

Pipeline Hazards

Advanced Geomechanics

Yinghui Tian University of Western Australia Structural Integrity University of Western Australia

Zhigang Xiao Monash Structural Integrity Monash University

Pathmanathan Rajeev Monash Structural Integrity Monash University

HongBo Liu Monash Seabed Integrity Monash University

Ming Zhao University of Western Australia Seabed Morphology University of Western Sydney

Zhipeng Zang University of Western Australia Seabed Morphology

Nathalie Boukpeti University of Western Australia Pipeline Hazards University of Western Australia

Dong Wang University of Western Australia Pipeline Hazards University of Western Australia

James Schneider University of Western Australia Pipeline Hazards University of

Wisconsin-Madison

Ying Wang University of Western Australia Pipeline Reliability Shanghai Jiao Tong University

Andrew Lammas Flinders Pipeline Monitoring Flinders University


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CSIRO Cluster Postgraduate Student Participants

NAME INST. THESIS TITLE CLUSTER STREAM

Name Inst. Thesis Title Cluster Stream

James Schneider UWA Analysis of piezocone data for displacement pile design Pipeline Hazards

Hongije Zhou UWA Numerical study of geotechnical penetration

problems for offshore applications

Seabed Characterisation

Han Eng Low UWA Performance of penetrometers in deepwater soft soil characterisation Seabed Characterisation

Matthew Hodder UWA Geotechnical analysis of offshore pipelines and steel catenary risers Structural Integrity

Di Wu UWA Experimental and numerical modelling of natural backfill

of navigation channels and pipeline trenches

Seabed Morphology

Grant Pusey Curtin Characterisation of long-range horizontal performance

of underwater acoustic communication

Pipeline Monitoring

Siti Fatin Mohd Razali UWA Wake characteristics of yawed circular cylinders and suppression

of vortex-induced vibration using helical strakes

Seabed Morphology

Xuelin Peng UWA Condition monitor ing of offshore pipelines using v ibration based method Pipeline Monitor ing

Jaya Kumar Seelam UQ Tsunami induced bed shear stresses- project Pipeline Hazards

Benham Shabani UQ Ben contr ibuting to the modelling of Jaya's but PhD otherwise unrelated Pipeline Hazards

Andrew Lammas Flinders Degree of Freedom Nav igat ion Systems for

Autonomous Underwater Vehicles

Pipeline Monitoring

Matthew Kokegei Fl inders Fully Coupled Degree of Freedom Control Systems

for Autonomous Underwater Vehicles

Pipeline Monitoring

Yan Yue UWA Novel methods for characterising pipe-soil

interaction forces in-situ in deep water

Seabed characterisation

Bassem Youssef UWA Use of probabili ty models in the integrated analysis in offshore pipelines Structural Integr ity

Zhihui Ye UWA Erosion threshold and erosion rate of seabed sediments Seabed Characterisation

Santiram Chatterjee UWA Modelling of pipeline seabed interactions Seabed Characterisation

David Roberts Flinders Pipeline Tracking Using Scanning Sonar Imaging Pipeline Monitoring

Tae-hwan Joung Flinders Computational F luid Dynamics Modell ing Techniques for

Analysing the Performance of a AUV Thruster

Pipeline Monitoring

Lyndon Whaite Flinders Mesh Free Methods for Probabilist ic Opt imal Control andEstimation of Autonomous Underwater Vehicles Pipeline Monitoring

Fauzan Sahdi UWA Modelling of submarine slides and their impact on pipelines Pipeline Hazards

Amin Rismanchian UWA Three dimensional modelling of pipeline buckling on soft clay Seabed Characterisation

Senthilkumar

Muthukrishnan

Monash Offshore pipe clay seabed interaction in axial direction Structural Integrity

Chunxiao Bao UWA Vibration based structural health monitoring

of onshore and offshore structures

Pipeline Reliability

Indranil Guha UWA Structural analysis of submarine pipelines under

submarine slide and thermal loading

Pipeline Hazards

Hossein Khalilpasha UQ Propagation buckling of deep subsea pipelines Structural Integrity

Hamed Mahmoodzadeh

Poornaki

UWA Interpretation of partially drained penetrometer tests with

applications to the design of spudcan foundation

Seabed Characterisation

Hassan Karampour UQ Coupled upheaval/lateral and propagation buckling of ultra-deep pipelines Structural Integrity


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Scientific and engineering challenges

The Subsea Pipeline Collaboration Cluster investigated and developed scientificsolutions to overcome the challenges of constructing pipelines from oil and gas

reserves in water depths exceeding metres.

For safe and economic developments

such pipelines are required to

maintain their structural integrity and

continuously supply hydrocarbons

across hundreds of kilometres of

rugged, often shifting, seabed to

bring the hydrocarbons to shore.

The Cluster brought together a diverse

range of research capabilities to deliver

an in-depth scientific understanding

of subsea pipelines in the areas of:

◆ design

◆ construction

◆ long-term operation

◆ real-time monitoring.

The aim of the program was to provide

a technical basis for the design of

pipelines for any new offshore field,

which contrasts with the current

case-by-case approach, significantly

reducing costs and uncertainties

for future pipeline design projects,

with part icular relevance to remote

offshore locations around Australia.

There were six research streams

which mimicked the life cycle of a

pipeline, from characterising the

design environment to monitoring

any risk of failure during operation.

These streams were:


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Sea-bed amplitude map showing featuresof the Gorgon slide, North West Shelf

Full-life reliability

This research assessed the feasibility of

using vibration measurement to monitor

the health of pipelines, with the aim

of replacing expensive and irregular

visual monitoring with continuous

measurements and analysis. Bothnumerical simulation and experimental

test results indicate that vibration

measurement is very sensitive to

pipeline scouring damage. Methods

were developed for possible applications

to monitor pipeline conditions online.

Pipeline monitoring

Research explored the use of

autonomous underwater vehicles

(AUVs) for continuous monitoring,

assessment of pipeline integrity and

evaluation of the seafloor, and theautonomous operation of an underwater

communication link between acoustic

modems. The scope of the AUV work

included developing new navigation,

control, and guidance techniques.

These new techniques aimed to improve

a vehicle’s capability to move more

accurately over long distances while

working close to objects; to detect and

track pipelines; and to manoeuvre to

deploy instruments into the seabed.

The technical detail and major

outcomes will now be presented foreach of these research streams.

Seabed characterisation

This project concentrated on

advanced testing of seabed sediment

characteristics to understand how they

may affect pipelines resting on the

seabed. Current methods practised in

industry are hampered by the expense

of having to conduct multiple tests

along a long pipe route, inaccuracies

in interpreting site-characterisation

tools developed for traditional deep

foundation rather than the top m layer

of soil, and difficulties of collecting soil

samples for onshore laboratory testing.

Novel equipment and interpretative

methods were developed to define

the main engineering parameters

required for pipeline design, such as

seabed strength and the effects of

seabed erosion. These included the

piezoball, toroidal and hemisphericalshallow ball penetrometers.

UWA miniature piezoball

Seabed morphology

Research was conducted into the

formation mechanisms of seabed sand

waves and in developing a model to

predict the evolution of sand waves with

and without the presence of a pipeline.

The project developed methods to

predict the three-dimensional erosion

of the seabed under pipelines.

Pipeline stability studies inthe miniature O-tube

Structural integrity

This project developed new numerical

models and design frameworks for

the analysis of pipeline stability and

fatigue by integrating the interactions

and effects of the seabed, currents

and waves on the pipeline structure.

Pipeline hazards

Deep-water developments require

pipeline routing up the continental

slope in areas of changing seabed

morphology and other geohazards. One

key technical challenge addressed by the

Cluster was the impact of a submarine

landslide sliding down the continental

slope and colliding with a pipeline.

Based on physical and numerical

modelling, this research developed

new calculation methods and analysistools. These tools were used to model

the run-out of submarine slides and to

assess their consequent impact forces

and potential damage to submarine

pipelines, together with an assessment

of tsunami-induced bed shear stresses

and pressure gradients on the sea floor.


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Scientific outcomes

The following are the major scientific outcomesof the Subsea Pipeline Collaboration Cluster

◆ Development of novel penetrometersand techniques for interpreting soil

properties, including an enhanced

ball-shaped penetrometer – the

piezoball – and new toroidal and

hemispherical devices for deployment

at the seabed. These devices are

already being used in practicalapplications offshore, where they are

deriving soil properties in the upper

metre of soil, the most relevant part

of the seabed for pipeline design.

◆ Development of a methodology forinterpreting pipeline axial friction

design values from novel toroidal and

hemispherical penetrometer results.

Miniature piezoball in beam centrifuge

◆ Complementary geotechnicalcentrifuge and field testing of the

piezoball penetrometer at UWA, theRiverside site in East Perth and the

Kvenild and Dragvoll sites in Norway

(the latter in collaboration with the

Norwegian University of Science and

Technology). The tests examined

the transition between intact and

remoulded shear strength, as well

as dissipation tests to examine

the consolidation properties of

the soil. Both are essential in the

interpretation of seabed properties

for design of deepwater pipelines.

◆ Proposed interpretative methodfor adjusting measured piezoballresistance to allow for the effects

of partial consolidation.

◆ Established new solutions for theinteractive forces between pipelines

and the seabed during axial and lateralmovement, on both coarse-grained

and fine-grained seabeds, with these

solutions being encapsulated into an

efficient macroelement framework.

Distribution of excess pore pressureafter a -diameter penetration

Piezoball testing in Trondheim – (from left) Noel Boylan (formerly COFS), Mike Long(UCD), Annika Bihs (NTNU), Jan Jønland (NTNU) and Roselyn Carroll (UCD)


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Profiles of (a) u and umball (b) Bq and Bmball

Softening

factor...............

u and uumball (kPa)

Bq and Bumball

. . .

D e p t h ( m )

D e p t h ( m )

Piezocone

Piezoball

u0

(a) u/D = .

(b) u/D = .

(c) u/D =

(d) u/D =


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◆ Established framework forincorporating macroelement pipe-

seabed models into structural

analysis programs, including

uplift and reattachment.

◆ Extension of plasticity modelsdescribing the pipe-soil load

displacement behaviour on

Australia’s calcareous sands to lateral

displacements of up to five diameters.

◆ Development of numerical analysis

code for integrated storm loadingon on-bottom pipelines.

◆ Proposed formulae to calculate thenatural frequency of free spanning

subsea pipelines by considering

the boundary conditions, mass

of hydrocarbon products, axial

force and multiple spans.

◆ Development of numerical analysisusing boundary element method

to predict the fatigue life of subsea

pipelines subject to combined actions.

◆ Development of a numericalmodel that simulates sand wave

formation and evolution.

◆ Verification of the RegionalOceanographic Modelling System

(ROMS) model for sand wave

migration and sand wave-pipeline

interaction model against offshore

data and comparison of numerical

results to other published models.

◆ Establishment of a numerical

model for three-dimensionalflow and scour under pipelines,

and subsequent validation of the

model against experiments.

◆ Analysis of initial embedment andsubsequent axial displacement

coupling pore pressure dissipation

and soil deformation.

◆ Analysis of the influence of boundaryconditions, hydrocarbon products and

axial pipeline tension on the natural

frequency of on-bottom pipelines.

◆ New convolution models tocalculate total bed shear stresses

for solitary waves and breaking

tsunami wave fronts.

◆ Establishment of state-of-the-art experimental equipment for

ongoing testing to support the

design of Australia’s offshore

pipelines, including:

– the world’s first facility

for simulating submarine

slides at small scale within ageotechnical drum centrifuge

– a pressurised testing vessel of m

length and mm internal diameter

that is rated for MPa and capable

of simulating the propagation

of pipeline buckling during deep

water installation and operation

(up to m water depth)

(a) (b)

Example of video footage images of (a) a pipeline crossing a sleeper and (b) an as-laid survey in silt


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– an experimental testing rig for

studying general and field specific

cyclic axial interaction behaviour

between the pipe and soil behaviour

for general loading under drained

or undrained conditions

– a mini O-tube facility for testing

of soil erosion properties

and small scale modelling ofseabed-infrastructure-ocean

interaction, allowing observations

of the flow conditions and

measurement of the erosion

threshold of seabed sediments

– establishment of laboratory testing

apparatus to measure bed shear

stress under tsunami-shaped waves

– development of capabilities for

simulating whole-life loading

histories on model pipes in the

geotechnical centrifuge, including

storm-induced hydrodynamic

load sequences, and thermally-

induced lateral buckling cycles

– development of miniaturisedversions of new field-scale

penetrometers, to allow

comparative testing of reconstituted

and in situ seabed sediments, in

support of centrifuge model testing.

◆ Validation of vibration-based methodsto reliably monitor the condition

of subsea pipelines (though their

practical implementation still depends

on a number of issues including

the ability to transmit the vibration

data and power the sensors).

◆ For the application of autonomousunderwater vehicles, the project

developed:

– a new full-order particle filter

based navigation algorithm that

can estimate an autonomous

underwater vehicle’s position,

attitude, velocity, and rotational

rates, as well as water currents

acting on the vehicle

– a fully-coupled control algorithm

to achieve improved manoeuvring

close to hazards and reduce

battery consumption

– a pipeline tracking system that can

detect and track multiple pipelines

– hardware and software modules that

embed these navigation, control

and guidance system in an AUV.

◆ Development of hardware andsoftware for controlling and

monitoring the performance of

underwater acoustic modems, while

simultaneously recording the ambient

noise and modem transmissions

on a wide-bandwidth recorder.

◆ Underwater acoustic modemsevaluated for their capacity to transmit

data along a pipeline. Long-term,

-day trials of a five-k ilometre

communication link between two

seabed-mounted modems in m

allowed detailed comparisons to be

made between measured modem

performance and performance

predicted by numerical simulators.

Mini o-tube facility


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Putting the Cluster’s research into practice

The Collaboration Cluster’s work has revolutionised subsea pipeline technology andits findings have already been implemented in oil and gas projects off Australia and

elsewhere in the world.

Meanwhile, four other long-distance

pipelines – Gorgon, Wheatstone, Ichthys

and Browse – are at an advanced stage

of design, and many shorter pipelines are

being designed. These new pipelines are

technically very challenging: some will

extend into deeper waters, well beyond

the shelf break, and some – notablythose to the Ichthys and Browse fields

– will be located north of Broome, in

different oceanographic and geotechnical

conditions compared to the existing

experience in the Carnarvon basin.

The new challenges of new regions,

greater pipeline lengths, deeper water and

new geohazards, have all been tackled

within the Cluster, and the research

techniques and outcomes spearheaded by

the Cluster have already been applied to

the design of Australia’s new pipelines.

These same technologies have also beenapplied to projects elsewhere in the

world, such as for BP’s PSVM field off

Angola, West Nile Delta offshore Egypt

and Shah Deniz in the Caspian Sea. This is

recognising Australia’s technical leadership

in pipeline engineering and the pivotal

role this Cluster has played in developing

testing facilities and design practises.

The Cluster’s research programs resulted

in several industry advances such as:

◆ improved site characterisation

through new technologies ◆ specialised geotechnicalcentrifuge testing

◆ advanced numerical modelling

◆ cyclone simulation experiments in thenewly established O-Tube facility.

Also, through a joint industry project

involving six offshore operators (BHP

Billiton Petroleum, BP, Chevron, Petrobras,

Shell and Woodside), new approaches

for geohazard assessment have been

derived and applied in projects, including

the Abillion Gorgon project in

north-west Western Australia thatinvolves designing a pipeline to travel

from m water depth at the Greater

Gorgon gas fields to the LNG plant

on Barrow Island, near Karratha.

Key aspects of the Cluster’s innovative

contributions to pipeline technology

include

Industry Impact through

Geotechnical Centrifuge Testing

Two critical components of pipeline

design are the assessment of on-bottomstability under severe hydrodynamic

loading – from storms or tides – and

the overall response of the pipeline

to internal temperature and pressure.

Under both conditions, the pipe may be

permitted to move significant distances

back and forth across the seabed, but

these movements must not be excessive

and the pipe must not be over-strained.

A critical input to assessment of pipeline

stability under these movements is the

interaction forces between the pipe and

the seabed. Centrifuge model testing,using offshore soil samples and accurate

simulation of the pipeline weight and

movements, provides observations

that can be used to refine and validate

models for pipe-soil interaction, leading

to reduced design uncertainty. New

experimental techniques were developed

at UWA during the Cluster project, and

these have resulted in more realistic

simulations of pipeline behaviour. Using

these techniques, centrifuge testing

has been performed over the past fouryears, using natural soil samples gathered

from offshore and providing results

that have had direct impact the design

of offshore field pipelines. The specific

projects, operators and pipe details are

provided in the table on following page.

Existing pipeline

Proposed pipeline

Ichthys

Browse

Gorgon

Wheatstone

Industry collaborator Paul Brunning ofAcergy presenting at the CSIROFlagship Cluster on Pipelines workshop


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OPERATOR PROJECT YEAR PIPELINE LENGTH MAIN TESTING FOCUS

Woodside Pluto km Lateral buckling

BP PSVM km Lateral buckling

Chevron Gorgon km & km As-laid embedment

Chevron Gorgon km Storm stability

Chevron Gorgon km Free span stability

Chevron Wheatstone km Buckling, storm stability

BP BSE km Lateral buckling

Inpex Ichthys (infield) km Lateral buckling

Woodside Browse km Buckling, storm stability

Inpex Ichthys (export) km Lateral buckling

BP West Nile Delta km Lateral buckling

BP Shah Deniz km Lateral buckling

Summary of centrifuge tests conducted for industry during the Cluster

Berms of soil along pipe in a industry test

These centrifuge studies used new

modelling technology that permits

arbitrary patterns of load and

displacement to be imposed on a model

pipeline. This allowed the effects of

dynamic laying, thermal start-up and

shutdown cycles and hydrodynamic

storm loading to be simulated. In somecases, stochastic storm simulations to

assess the pipe-soil response during

-year and -year return

period design events were devised. The

underlying technology is described later

in this report (also refer to centrifuge

modelling technology section).

Industry impact through

numerical modelling

Numerical pipe-soil models were

incorporated into the industry stability

analysis package ABAQUS/SimStabfor use in the Gorgon Upstream

Joint Venture (GUJV) project. Cluster

researchers collaborated with GUJV

engineers in initially running the

plasticity UWAPIPE models under

Gorgon storm conditions, before

incorporating the models into the

SimStab software for GUJV engineers

to use. The new soil models are

now being used in the stability

analysis of the Gorgon pipeline on

the North West Shelf of Australia.

New methods to predictsubmarine slide-

pipelineinteraction

Research into the interaction between

submarine slides and pipelines formed

a major theme within the cluster,

and also a joint industry project

administered by the Minerals and

Energy Research Institute of Western

Australia (MERIWA Project M) and

sponsored by the six energy majors

BHP Billiton Petroleum, BP, Chevron,

Petrobras, Shell and Woodside. Annual

workshops between the sponsoring


21/56

Developing slide experimentsat the UWA drum centrifuge

Slide run-out from centrifuge test with compression ridges highlighted

Velocity distributions ondeformed softening material

companies and researchers were

held in Perth and in Houston, USA.

This project aimed to develop new

techniques to characterise and

model the geotechnical aspects

of submarine slide behaviour. The

project encompassed both physical

modelling and numerical modelling.A program of novel centrifuge model

tests generated a library of well-

characterised submarine slides, as well

as a database of slide-pipe interaction

force measurements. These results were

used to validate numerical run-out

computations that were performed

using two levels of sophistication – a

new, and more refined, implementation

of the industry- standard depth-averaged

approach, and a continuum-based large

deformation finite element method.

The techniques emerging from this

research into the assessment of

pipeline-slide loading have beenapplied to the Greater Gorgon

development, offshore Australia.

A further significant part of the

project was the development of a new

geotechnically-based framework to

characterise the strength of soft seabed

deposits, based on extensive laboratory

measurements using different soil

types. This framework spans the solid-

fluid boundary that is crossed within

the slide material as it evolves into a

debris flow and, ultimately, a turbidity

current. In addition, extensive analyticalstudies were performed to support

the development of new models for

the interaction forces between slides

and pipelines, and these were dist illed

into simple design recommendations.

z ( m )

0

10

20

30

z ( m )

0

10

20

30

z ( m )

0

10

20

30

x (m)

z ( m )

110 120 130 140 150 160 170 180 1900

10

20

30

Velocity (m/s)1.45

1.35

1.25

1.15

1.05

0.95

0.85

0.75

0.65

0.55

0.45

t = 0.1 s

Velocity (m/s)3.6

3.3

3

2.7

2.4

2.1

1.8

1.5

1.2

0.9

0.6

0.3

0

t = 3.3 s

Velocity (m/s)0.12

0.11

0.1

0.09

0.08

0.07

0.06

0.05

0.04

0.03

0.02

0.01

t = 15 s

Velocity (m/s)0.12

0.11

0.1

0.09

0.08

0.07

0.06

0.05

0.04

0.03

0.02

0.01

t = 69 s


22/56



23/56

Commissioning experimental equipmentor ongoing pipeline testing in Australia

Major equipment development:

Piezoball penetrometers are now

used routinely by the Australian site

investigation company, Benthic Geotech,

in its portable remotely operated drill

(PROD). Extensive data were obtained

in for Woodside’s Browse project

on the North-West Shelf. ROV-

mounted penetrometer capabilities

have been developed by companies

such as Perry Slingsby in the USA (the

Rovdrill) and Geomarine in the UK.

Piezoball tests carried out in the project

have also given an insight into the

interpretation of data in silty carbonate

sediments found offshore Australia.

For pipeline design, an important

parameter is the axial friction between

pipe and soil. New devices have been

developed during the project to target

this parameter, by applying torsional

loading to a toroidal penetrometer,

or to an alternative hemi-spherical

penetrometer. In both cases, the

torsional interface response between

the device and soil represents a close

analogue of the axial sliding resistance

of a pipeline. Test data at model scale,

supported by numerical analysis, have

quantified the relationships between

axial friction and both the elapsed time

and velocity of shearing. Analytical

solutions have also been developed that

capture these contributions for different

soil types, thus providing a method for

interpreting data from the equipment.

T-bar penetrometers test on remouldedsample of carbonate silt

Penetrometers for pipeline site investigation

The offshore industry has already made significant advances in site

investigation techniques, incorporating full-flow penetrometers such

as the T-bar and piezoball devices originally developed at UWA.


24/56


These include:

◆ An improved motion control systemenabling the modelling of pipeline

dynamic installation with complexhorizontal and vertical motion

interaction and the modelling of

pipeline buckling (Figure b) up to

cycles. This is a major improvement

compared to the previous modelling

capability (limited to about

cycles), which revealed specific

features of pipe soil interaction

related to the development of

berms and pipe embedment

over a large number of cycles.

◆ The establishment of a new drivingsystem for the tool table of the drum

centrifuge and a new experimental

pipe apparatus. This upgrade was

triggered by the necessity to allow a

buried model pipeline to be translated

at various velocities through a soil

sample contained within the drum

centrifuge channel, simulating a pipe

engulfed within a submarine slide. By

using a soil sample which was initiallyunconsolidated, the model pipe

tests were performed after different

degrees of consolidation leading to

varying sample properties (density

ρ and undrained shear strength su).

Pipe translation tests were performed

using different model pipes with

varying length to diameter ratios

in order to determine the optimum

pipe geometry that would minimise

potential end effects. Once the test

technique was established the main

program of testing was undertaken.This involved a total of model pipe

translation tests spanning a wide

range of velocities and soil strengths.

◆ The establishment of optic fibredata transmission on both the beam

and the drum centrifuge improving

the transfer rate, increasing the

quality of the experimental dataand enabling high definition videos

to taken during experiments.

Horizontal displacement direction

Model pipeline during horizontal buckling Buried model pipeline translated through clay of various strengths

Christophe Gaudin and Yinghui Tian withthe beam centrifuge

UWA’s geotechnical centrifuges

Both the beam (Figure a) and the drum centrifuges at the Centre for Offshore Foundation

Systems have had continuous technical upgrades to face the challenges associated with

the buckling of pipelines and the impact of submarine slides on pipelines.


25/56

The mini O-tube was formulated as

part the Collaboration Cluster and

highlighted the feasibility of the

experimental testing approach. A larger

O-tube was then subsequently funded byUWA, the Australian Research Council,

and Woodside and Chevron, via the

STABLEPIPE Joint Industry Project.

The facility allows a full ocean-pipeline-

seabed interaction to be simulated at

large scale. Cyclonic wave and current

conditions can be created in the .

m high test section, flowing over a

m long mobile sediment bed. The

long-term aim is to allow seabed

mobility, manifested through scour

and liquefaction, to be incorporated

in simulations of pipeline on-bottomstability – which currently neglect these

potentially important processes.

This project is led by Liang Cheng,

with Hongwei An (UWA) and David

White and Mark Randolph. Support

for this initiative was provided by

Andrew Palmer (National University of

Singapore), as well as Woodside (Nino

Fogliani and Roland Fricke) and the local

consultancies JP Kenny (Terry Griffiths)

and Atteris (Eric Jas). Conference papers

describing the O-tube activity were

presented at the Offshore PipelineTechnology Conference (in Amsterdam)

and the ISOPE Conference (Shanghai).

Scott Draper with the miniature O-tube

The large o-tube, assembled at the UWA Shenton Park field station

O-tube

A new O-tube facility allows storm conditions to be simulated within a large recirculating flume.


26/56


The Monash Advance Pipe Testing System (MAPS)

Among these, propagation buckling

is the most critical one, particularly in

deep water, and can quickly damage

many kilometres of pipeline.

A local buckle, ovalisation, dent or

corrosion in the pipe wall can quicklytransform the pipe cross-section into

a dumb-bell (or dog bone) shape that

travels along the pipeline as long as the

external pressure is high enough to sustain

propagation. The lowest pressure that

maintains propagation is the propagation

pressure that is only a small fraction

of the elastic collapse pressure of the

intact pipe. This results in a substantial

increase in material and installation cost

of the pipeline, since design is therefore

governed by propagation pressure.

A hyperbaric chamber was constructed for

the simulation of propagation buckling

in ultra-deep subsea pipelines. Thepressurised testing vessel is m long with

an internal diameter of mm and is rated

for MPa ( m water depth). A testing

protocol was successfully established and

numerous tests were conducted on m

long steel and aluminium pipes. A simple

testing procedure using a ring segment

of the pipeline was also established as

a preliminary test. A modified analytical

solution for propagation buckling was

proposed and a finite element model

was established and verified with

the experimental results. Based on

these findings, a new pipe topology is

proposed. Finite element analysis of the

new pipe, a faceted cylinder, shows a

substantial increase in buckling capacity

for the same diameter/thickness ratio.

The coupling of upheaval and lateral

buckling with propagation buckling

is being investigated together with

exploring the possible modification

of the hyperbaric chamber to simulate

this form of coupled buckling.

A sophisticated D electrical actuator with

a precision of . mm/sec (to account

for the slow axial walking process) was

devised to simulate the pipe motion

on a laboratory-made clay seabed. A

horizontal linear motor capable of driving

the shaft with a drive force between

to N for a stroke length of

mm is provided. The vertical motion is

controlled by a motor providing to N drive force to an expected

stroke length of mm. Both load and

displacement controlled cycles can be

performed at different rates depicting

both undrained and drained conditions.

The system is suitable for element testing

of typical prototype pipe diameters.

Dummy sections at the ends of the test

pipe section are provided to reduce

boundary effects in simulation of a long

pipe. The following steps are used in a

typical experiment. First, a model seabed isprepared and characterised using a T bar.

Second, the test pipe is allowed to settle

on the model seabed. Third, the test pipe

is subjected to cyclic axial displacements

using the horizontal actuator. On the

basis of instrumentation provided, the

axial on the test pipe section, pore

water pressure at pre-determined

locations and vertical settlement of

pipe are measured. The test results

produce the shear stress-displacementcharacteristics of the pipe-soil interface

applicable to axial walking problems.

Propagation buckling

A subsea pipeline can experience a number of structural instabilities, such as lateral

(snaking) buckling, upheaval buckling, span formation and propagation buckling.

Axial pipeline walking

A testing system to investigate axial pipeline walking under drained and

undrained conditions has been established at Monash University, Australia.


27/56

The shear cell consists of a mm long,

mm wide and . mm thick smooth

plate supported on thin tubular sway

legs, with displacement measured by an

eddy-current sensor which resolves plate

movement to . mm. The wave flume

was equipped with a computer-controlled

piston wave-maker having a maximum

stroke length of . m and capable of

generating most types of waves including

solitary waves and bores. The experimental

model was set up to represent a

continental slope and shelf region, with

measurements made on the slope and

horizontal sections. Measurements were

made over both a smooth bed and a rough

bed. Both non-breaking and breaking

(bores) were investigated. Microsonic®

ultrasonic wave gauges were used to

measure the wave heights and a SONTEK®D Acoustic Doppler Velocimeter was used

to measure the flow velocities. A photo of

a physical model test for a solitary wave

is shown below. Numerical modelling

of the laboratory experiments has been

performed and used to calibrate and test

a tsunami model for prediction of seabed

shear stresses in the field.

Numerical modelling of tsunami sources

along the Sunda Arc has shown the

locations of principal hazard on the

WA continental slope and shelf, together

with hotspots of high bed shear stress,

both of which can be ut ilised in pipeline

routing studies.

A solitary wave at the shelf edge in the UQ experiments

Tsunami testing facility

Novel bed shear stress measurements were performed in the

UQ tsunami wave flume, which is m long and . m wide.


28/56


Battery operated, and mounted

in pressure proof housings, the

equipment controls the operation

of the modems and monitors their

performance while simultaneouslymonitoring ambient noise and the

water column temperature profile. It

has been successfully used for several

experiments, including a -day

unattended trial in m of water off

the Western Australian coast. It can

be readily modified to suit other types

of underwater acoustic modems.

The development of this hardware

has been complemented by

the development of a modem

performance simulator that can be

used to investigate the effects ofdifferent environmental factors on

communication link performance.

Acoustic modems

The capability to perform at-sea evaluations of underwater acoustic communication

links has been enhanced by the development of equipment to allow the unattended,

autonomous operation and monitoring of such links for extended periods of time.

Experimental setup for the long-term trial showing all equipment used in the deployment.Two sets of equipment were deployed which periodically communicated with one anotherwhile recording information including ambient noise levels and a temperature profile for thebottom m of the water column.


29/56

The developed algorithms must,

however, be physically validated

using a real vehicle equipped with the

necessary sensors and actuators.

The majority of AUVs currently available

from vendors are either closed

architecture which would prevent

alternative algorithms from being used

on the vehicle, or are too expensive,

or too small to be useful. The decision

was therefore taken to custom build a

modular vehicle that can satisfactorily

validate the developed algorithms

and with enough flexibility to meet

the range of survey/intervention

requirements posed by the offshore

oil and gas. This vehicle is currently

being built in collaboration with theAustralian Maritime College. The

vehicle is equipped with four lateral

thrusters as well as one propulsion

thruster permitting it to hover and hold

position while deploying instruments

into the seabed, and turn t ightly while

manoeuvring close to obstacles. The

AUV is equipped with forward looking

and bathymetry plus side scan sonar to

build D relief maps of the seabed and

track pipelines and obstacles. It also has

doppler velocity sensors and IMUs for

navigation, as well other instruments

for acoustic and radio communications.

CAD image of an AUV

Autonomous underwater vehicles

The algorithms developed to control, navigate and guide AUVs have all

been tested numerically using realistic purpose-built simulators.


30/56

Matt Hodder

Geotechnical analysis ofoffshore pipelines and steelcatenary risers

Matt Hodder’s thesis investigated

the interaction of cylindrical

objects with soil, and its application

to the analysis and design of

offshore pipelines and risers.The behaviour observed during

experiments performed to assess the

effect of various loading conditions

on pipe-soil interaction response was

used to develop analytical models

appropriate to use in an integrated

soil-structure interaction assessment of

the pipe-soil system. The apparatus and

analysis methodology developed allows

comparisons of behaviour observed

during experiments performed using

a short ‘element’ of pipeline assuming

two-dimensional plane-strain conditionsand the validation of pipe-soil interaction

models developed from element tests.

This thesis progresses the understanding

of geotechnical aspects of offshore

pipeline and riser behaviour. It also

advances the predictive capabilities

of pipe-soil interaction models,

enabling more accurate response

assessment and efficient design.

Postgraduate

profile


Publications and dissemination

Members of the Cluster have published journal and conference manuscripts from their research. A further

five technical reports were written specifically for the

cluster and three book chapters were published.

. Alam, M. S. and L. Cheng (), A -Dmodel to predict t ime developmentof scour below pipelines withspoiler, th International Conferenceon Enhancement and Promotion ofComputational Methods in Engineeringand Science, Hong Kong – Macau.

. Alam, M. S. and L. Cheng (),

Blockage ratio and mesh dependencystudy for Latt ice Boltzmann flow aroundcylinder, th International Conferenceon Enhancement and Promotion ofComputational Methods in Engineeringand Science Hong Kong – Macau.

. Alam, M. S. and L. Cheng (), Modellingof flow around a square cylinder of differentroughness using a lattice Boltzmannmodel, th International Conference onOcean, Offshore and Arctic Engineering,Honolulu, Hawaii, OMAE-.

. Alam, M. S. and L. Cheng (), Aparallel three-dimensional scour modelto predict flow and scour below a

submarine pipeline, Central European Journal of Physics , (): -.

. Albermani, F., H. Khalilpasha and H.Karampour (), Propagation bucklingin deep subsea pipelines, PipelinesInternational Digest, January : -.

. Albermani, F., H. Khalilpasha andH. Karampour (), Propagationbuckling in deep sub-sea pipelines,

Engineering Structures: (): -.

. An, H., L. Cheng nd M. Zhao ().Direct numerical simulation of D steaystreaming induced by Honji Instability.th Australasian Fluid Mechanics

Conference, Auckland, New Zealand.

. An, H., L. Cheng and M. Zhao (),Steady streaming around a circularcylinder in an oscillatory flow, OceanEngineering, (): -.

. An, H., Cheng, L., Zhao, M., (), Steadystreaming around a circular cylinder neara plane boundary due to oscillatory flow. ,

Journal of Hydraulic Engineering: (accepted).

. An, H., Cheng, L., Zhao, M. (), Directnumerical simulation of oscillatoryflow around a circular cylinder at lowKeulegan-Carpenter number, Journalof Fluid Mechanics, : -.

. Baldock , T. E., D. Cox, T. Maddux, J.Killian and L. Fayler (), Kinematicsof breaking tsunami waves: a data setfrom large scale laboratory experiments,

Coastal Engineering, : -.

. Baldock, T. E. and D. Peiris ().Overtopping and run-up hazards inducedby solitary waves and bores. TsunamiThreat - Research and Technology, In-Tech.

. Baldock, T. E. and J. K. Seelam (),Numerical and physical modellingof tsunami run-up and impact onsubsea pipelines, st Annual Society

for Underwater Technology SubseaTechnical Conference (SUT), Perth, CD.

. Bao, C. X., X.Q Zhu, H. Hao andZ.X. Li (), Operational modalanalysis using correlation-basedARMA models, th InternationalSymposium on Structural Engineering

for Young Experts, CD:-.

. Bao, C. X., X.Q Zhu, H. Hao and Z.X.Li (), Variable modal parameteridentification using an improvedHHT algorithm, th InternationalSymposium on Structural Engineering

for Young Experts, CD:-.

. Bao, C. X., H. Hao, Z.X. Li and X.Q.Zhu (), Time-varying systemidentification using an improvedHHT algorithm, Computers andStructures, (-): -.

. Barnes, M. P., T. O’Donaghue, J.M. Alsinaand T.E. Baldock (), Direct bed shearstress measurements in bore-drivenswash, Coastal Engineering, : -.

. Barnes, M. P. and T. E. Baldock (), ALagrangian model for boundary layergrowth and bed shear stress in the swashzone, Coastal Engineering,(): -.

. Boukpeti, N., D.J. White and M.F. Randolph(), Characterization of the solid-liquidtransition of fine-grained sediments,

th International Conference on OffshoreMechanics and Arctic Engineering,Honolulu, Hawaii, OMAE-.

. Boukpeti, N., D. White and M.F.Randolph () Analytical modellingof the steady flow of a submarineslide and consequent loading on apipeline, Géotechnique, () -.

. Boukpeti, N., D.J. White, M.F. Randolphand H.E. Low (), The strength offine-grained soils at the solid-fluidtransition, Geotechnique: in press, postedahead of print, ./geot..P..

. Boylan, N., C. Gaudin, D.J. White, M.F.Randolph and Schneider, J.A. (),Geotechnical centrifuge modellingtechniques for submarine slides, thInternational Conference on OffshoreMechanics and Arctic Engineering,Honolulu, Hawaii, OMAE-.


31/56

Grant Pusey

Characterisation of long-range horizontal performanceof underwater acousticcommunication

Grant’s study sought to characterise the

performance of horizontal underwater

acoustic data communication in

various scenarios with particularapplication to subsea monitoring

and control systems. This involved

conducting field trials to simultaneously

measure environmental parameters

and communication performance.

An underwater acoustic communication

simulator was also developed

and the results compared to the

experiments. This thesis investigates

the environmental dependency of

communication performance and the

feasibility of using the technology

in place of cabled telemetry.

Postgraduate

profile

. Boylan, N., C. Gaudin, D.J. White and M.F.Randolph (), Modelling of submarineslides in the geotechnical centrifuge,th International Conference on Physical

Modelling in Geotechnics (ICPMG ),Zurich, Switzerland CD:-.

. Boylan, N. and M. F. Randolph (),Enhancement of the ball penetrometertest with pore pressure measurements,

nd International Symposium on Frontiersin Offshore Geotechnics (ISFOG ),Perth, Australia, CD:-.

. Boylan, N. P., C. Gaudin, D.J. Whiteand M.F. Randolph (), Centrifugemodelling of submarine slides, OceanEngineering: under review April .

. Boylan, N. P. and D. J. White ().Geotechnical frontiers in offshoreengineering - invited keynote lecture.International Symposium on Recent

Advances and Technologies in CoastalDevelopment, Tokyo, Japan, CD: pages.

. Cassidy, M.J. and Y. Tian (),Technical note on pipesoil datainteraction model testing, GEO:.

. Cassidy, M.J. and Y. Tian (),Technical note on implementation ofUWAPIPE into ABAQUS, GEO:.

. Chatterjee, S., D.J. White, D. Wangand M.F. Randolph (), Largedeformation finite element analysis ofvertical penetration of pipelines into theseabed, nd International Conference in

Frontiers in Offshore Geotechnics (ISFOG ), Perth, Australia, n/a:-.

. Cheng, L., K. Yeow, Z. Zang and B.Teng (), Three-dimensional scourbelow pipelines in steady currents,

Coastal Engineering, (-): -.

. Davies, M. C. R., E.T. Bowman and D.J.White (), Physical modelling ofnatural hazards - a keynote lecture, thInternational Conference on PhysicalModelling in Geotechnics (ICPMG ) Zurich, Switzerland, CD:-.

. DeJong, J., N. Yafrate, D. DeGroot, H.E. Lowand M.F. Randolph (), Recommended

practice for full flow penetrometertesting and analysis, ASTM GeotechnicalTesting Journal, (): pages.

. DeJong, J. and M. F. Randolph (),Influence of partial consolidationduring cone penetration on estimatedsoil behaviour type and pore pressuredissipation measurements, Journalof Geotechnical & GeoenvironmentalEngineering, (): -.

. DeJong, J. T., N.J. Yafrate and M.F.Randolph (), Use of pore pressuremeasurements in a ball full-flowpenetrometer, rd International Conferenceon Site Characterization, Taiwan, -.

. Gaudin, C., D.J. White, N. Boylan, J.Breen, T.A. Brown, S. De Catania and P.Hortin (), A wireless high speed dataacquistion for geotechnical centrifugemodel testing, Measurement Scienceand Technology, (): pages.

. Guard, P. A., T.E. Baldock and P. Nielsen(), Bed shear stress in unsteadyflow, Coasts and Ports, Wellington, NZ.

. Hodder, M., M.J. Cassidy and D.

Barrett (), Undrained responseof pipelines subjected to combinedvertical and lateral loading, ndInternational Conference on Foundations(ICOF), Bracknell, UK, CD:-.

. Hodder, M. S., White, D.J., Cassidy, M.J.() An effective s tress framework forthe variation in penetration resistancedue to episodes of remoulding andreconsolidation,Géotechnique, (): -.

. Hodder, M. S., D.J. White and M.J.Cassidy (), Effect of remouldingand reconsolidation on the touchdownstiffness of a steel catenary riser:Observations from centrifuge modelling,

st Offshore Technology Conference,Houston, Texas, OTC-.

. Hodder, M. S. and M. J. Cassidy (), Aplasticity model for predicting the vert icaland lateral behaviour of pipelines in claysoils, Geotechnique, (): –.

. Hodder, M. S., D. J. White, et al. (),Analysis of strength degradation duringepisodes of cyclic loading, illustrated bythe T-bar penetration test, International

Journal of Geomechanics , (): -.

. Jaeger, R. A., J.T. DeJong, R.W. Boulanger,H.E Low and Randolph, M.F. (),Variable penetration rate CPT in an

intermediate soil, nd InternationalSymposium on Cone Penetration Testing,CPT, Huntington Beach, California.

. Khalilpasha, H. (). Buckling propagat ionof subsea pipelines. EAIT PostragraduateStudent Conference, Queensland, Australia.

. Khalilpasha, H. (). Nonlinearnumerical investigation of bucklepropagation in subsea pipelines. The stInternational Postgraduate Conference onEngineering, Designing and Developingthe Built Environment for SustainableWellbeing, Br isbane, Australia.

. Khalilpasha, H. and F. Albermani ().

On the propagation buckling and effectsin ultra-long deep subsea pipelines.

th International Conference on Ocean,Offshore and Arctic Engineering (OMAE

), Rotterdam, The Netherlands.

. Kodikara, J. K. (). Study of the axialresponse and its coupling of the generalpipe-soil interaction of seabed pipelines.

. Kokegei, M., F. He and K. Sammut (),Fully-coupled degress-of-freedom controlof autonomous underwater vehicles,IEEE Oceans , submitted July .

. Kokegei, M., F. He and K. Sammut (),Nonlinear fully-coupled control of AUVs,

st Annual Society for Underwater SocietySubsea Technical Conference (SUT), Perth.

. Kokegei, M., He, F. and Sammut, K.(). Fully coupled DoF control of anover-actuated autonomous underwatervehicle. Underwater Vehicles, InTech.


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. Lammas, A., K. Sammut and He,F. (), Improving navigationalaccuracy for AUVs using the MAPRparticle filter, IEEE Oceans .

. Lammas, A., K. Sammut and He, F.(). -DoF navigation systems forautonomous underwater vehicles. MobileRobots Navigation, In-Tech Books.

. Lammas, A., K. Sammut and He, F. (),MAPR particle filter for AUV sensor fusion,

st Annual Society for Underwater SocietySubsea Technical Conference (SUT), Perth.

. Lammas, A. S., K. and He, F. (),Measurement-assisted partial resamplingparticle filter for full-order state-estimationof an AUV’s hydrodynamic parameters, IEEEOceanic Engineering: submitted April .

. LeBlanc, C. and M. F. Randolph (),

Interpretation of piezocones in silt,using cavity expansion and critical statemethods, th International Conferenceof International Association for ComputerMethods and Advances in Geomechanics(IACMAG), Goa, India, CD:-.

. Lee, J. and M. F. Randolph (),Penetrometer based assessment ofspudcan penetration resistance, Journalof Geotechnical & GeoenvironmentalEngineering: (): -.

. Lehane, B., C. O’Loughlin, C. Gaudinand M.F. Randolph (), Rateeffects on penetrometer resistance inkaolin, Geotechnique, (): -.

. Li, Y. H., K.Q. Fan, X.Q. Zhu and H. Hao(), Operational modal identificationof offshore structures using blindsource separation, st Annual Society forUnderwater Technology Subsea TechnicalConference (SUT), Perth, CD: SUT-LiYH.

. Liu, H. B., X.L. Zhao and Z.G. Xiao (),Fatigue testing of subsea pipelinesteel connections under combinedactions, The st Australasian Conferenceon the Mechanics of Structures andMaterials, Melbourne, -.

. Liu, H. B. and X. L. Zhao (). Predictionsof fatigue life of steel connections

under combined actions using boundaryelement method. st InternationalOffshore and Polar EngineeringConference, Maui, Hawaii, : -.

. Liu, H. B. and X. L. Zhao (). Fatiguebehaviours of subsea pipeline steelconnections under combined actions.th International Conference on Advancesin Steel Structures, Nanjing, China.

. Liu, H. B. and X. L. Zhao ().Fracture mechanics analysis of steelconnections under combined actions.th International Conference on Advancesin Steel Structures, Nanjing, China.

. Liu, H. B. and X. L. Zhao (). Repairefficiency of CFRP reinforced steelconnections under combined actions.th International Conference on FibreReinforced Polymer Composites inCivil Engineering, Rome, Italy.

. Liu, H.B, and X.L. Zhao (), FatigueBehaviour of Welded Steel Connectionsunder Combined Actions, Advancesin Structural Engineering – An

International Journal, (): -.. Liu, H.B and X.L. Zhao (), Prediction

of fatigue life for CFRP strengthenedsteel connections under combinedloads, International Journal of StructuralStability and Dynamics, (): DOI:./S

. Low, H. E., M.F. Randolph, C.J.Rutherford, B.B. Bernard and J.M.Brooks (), Characterization ofnear seabed surface sediment, OffshoreTechnology Conference, OTC.

. Low, H. E., M.F. Randolph, J.T. DeJong andN.J. Yafrate (), Variable rate full-flowpenetration tests in intact and remouldedsoil, rd International Conference on SiteCharacterization , Taiwan, -.

. Low, H. E., T. Lunne, K.H. Andersen,M.A. Sjursen, M.A., X. Li and M.F.Randolph (), Estimation of intactand remoulded undrained shearstrengths from penetration tests in softclays, Geotechnique, (): -.

. Low, H. E., M. F. Randolph, T. Lunne, K.H.Andersen and M.A. Sjursen () Effectof soil characteristics on relative valuesof piezocone, T-bar and ball penetrationresistance, Geotechnique, (): -.

. Low, H. E., M.M. Landon, M. F.

Randolph and D. DeGroot, ()Geotechnical characterisation andengineering properties of Burswoodclay, Geotechnique, (): -.

. Low, H. E. and M. F. Randolph (),Strength measurement for nearseabed surface soft soil, Journal ofGeotechnical and GeoenvironmentalEngineering, (): -.

. Lunne, T., K.H. Andersen, H..E. Low,M. F. Randolph and M.A. Sjursen,() Guidelines for offshore in situtesting and interpretation, CanadianGeotechnical Journal, (): -.

. Mahmoodzadeh, H., N, Boylan, M.F.Randolph and M.J. Cassidy (). Theeffect of par tial drainage on measurementsby a piezoball penetrometer. thInternational Conference on Ocean Offshoreand Arctic Engineering (OMAE),Rotterdam, The Netherlands.

. Merifield, R. S., D.J. White and M.F.Randolph (), The effect of pipe-soil interface conditions on undrainedbreakout resistance of partially-embedded pipelines, th InternationalConference on Advances in ComputerMethods and Analysis in Geomechanics(IACMAG), Goa, India, CD:-.

. Merifield, R. S., D.J. White and M.F.Randolph (), The effect of surfaceheave on the response of partially-embedded pipelines on clay, Journalof Geotechnical and GeoenvironmentalEngineering, (): -.

Bassem Yousse

The Integrated Stability Analysisof Offshore Pipelines

The dissertation is concerned with the

stability analysis of offshore pipelines

under wave and current loading. An

integrated hydrodynamic-pipe-soil

modeling program is developed and

used in investigating the pipeline

stability in conditions found on the

Australian North West Shelf and the

Gulf of Mexico. The developed program

is a combination of three individual

programs to perform an integrated

pipeline simulation. A hydrodynamic

modelling program that generates

D ocean surface, estimates the wave

kinematics at the pipeline level and

calculates the hydrodynamic loads on the

pipeline. A pipe-soil modelling program

that simulates the complicated pipe-soil

interaction behaviour under complex

hydrodynamic loading. The pipelineis modelled using the commercial

finite element program ABAQUS.

Advanced statistical methods are

utilized in the thesis to investigate

the reliability of the pipeline stability

and the sensitivity of the design

input parameter. Pipeline centrifuge

modeling is conducted under complex

hydrodynamic loading, with the results

used to validate the integrated program.

The study provides engineers with a

D pipeline modeling program and

methodologies to achieve reliableand economic pipeline designs.

Bassem received an Innovation Award

Commendation from the Australian Gas

Technology Conference (Perth-)

for the development of the integrated

pipeline simulation program.

Postgraduate

profile


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. Osman, A. S. and M. F. Randolph(), Response of a solid infinitecylinder embedded in a poroelasticmedium and subjected to a lateral

load, International Journal of Solidsand Structures, (-): -.

. Peng, X. L. and H. Hao (), Damagedetection of underwater pipeline usingvibration-based method, rd WorldCongress on Engineering Asset Managementand Intelligent Maintenance System.

. Pusey, G., A. Duncan and A. Smerdon(), Analysis of acoustic modemperformance for long rangehorizontal data transmission, OCEANS IEEE Bremen, Germany.

. Pusey, G. (). Character isation oflong-range horizontal performance ofunderwater acoustic communication,Curtin University, PhD Thesis.

. Pusey, G. and A. Duncan (),Characterisation of underwateracoustic modem performance forreal-time horizontal data transmission,

Australian Acoustical Society AnnualConference , Geelong.

. Pusey, G. and A. Duncan (),Development of a simplistic underwateracoustic channel simulator for analysis andprediction of horizontal data telemetry,

Australian Acoustical Society Nat ionalConference, Adelaide, abstract submitted.

. Pusey, G. and A. Duncan (), An

investigation of oceanographic parametersaffecting acoustic modem performance forhorizontal data transmission, Underwater

Acoustic Measurements Technologiesand Results rd International Conferenceand Exhibition, Nafplion, Greece.

. Pusey, G. and A. Duncan (), Apreliminary study of underwater acousticcommunications over horizontal ranges,st Annual Society for Underwater SocietySubsea Technical Conference (SUT) Perth, CD.

. Randolph, M. F., D. Wang, H. Zhou,M.S. Hossain and Y. Hu (),Large deformation finite elementanalysis for offshore applications,th International Conference ofInternational Association for ComputerMethods and Advances in Geomechanics(IACMAG), Goa, India, CD:-.

. Randolph, M. F., D. Seo and D.J.White (), Parametric solutionsfor slide impact on pipelines, Journalof Geotechnical & GeoenvironmentalEngineering, (): -.

. Randolph, M. F., C. Gaudin, S.M.Gourvenec, D.J. White, N. Boylan andM.J. Cassidy (), Recent advances inoffshore geotechnics for deepwateroil and gas developments, Ocean

Engineering, special issue: (): -.. Randolph, M. F. and P. Quiggin (),

Non-linear hysteretic seabed model forcatenary pipeline contact, th InternationalConference on Offshore Mechanics

and Arctic Engineering (OMAE ),Honolulu, Hawaii, OMAE-.

. Randolph, M. F. and D. J. White (),Offshore foundation design – a

moving target. Keynote paper, ndInternational Conference on Foundations(ICOF), Bracknell, UK, -.

. Randolph, M. F. and D. J. White (),Pipeline embedment in deep waterprocesses and quantitative assessment,Offshore Technology Conference, OTC.

. Randolph M.F. and D.J. White (),Interaction forces between pipelinesand submarine slides - a geotechnicalviewpoint. Ocean Engineering, , -.

. Rognon, P. G., I. Einav and C. Gay(), Internal relaxation time inimmersed particulate materials,

Physical Review E, : .

. Rognon, P. G., I. Einav, J. Bonivin andT. Millar (),A scaling law for heatconductivity in sheared granular material,Europhysics Letters, , pp .

. Rognon, P. G. and C. Gay (), Softdynamics simulation : normal approachof two deformable particles in a v iscousfluid and optimal-approach strategy, TheEuropean Physics Journal, : -.

. Rognon, P. G. and C. Gay (), Softdynamics simulation : elastic spheresundergoing T process in a v iscous fluid,The European Physics Journal, : -.

. Schneider, J. A., M.F. Randolph, P.W.Mayne and N. Ramsey (), Analysisof factors influencing soil classificationusing normalized piezocone tip resistanceand pore pressure parameters, Journalof Geotechnical and GeoenvironmentalEngineering, (): -.

. Schneider, J. A., M.F. Randolph, P.W.Mayne and N. Ramsey (), Influence ofpartial consolidation during penetrationon normalised soil classification bypiezocone, rd International Conference onSite Characterization, Taiwan, -.

. Seelam, J. K., P.A. Guard and T.E. Baldock

(), Measurements and modelling ofbed shear stress under solitary waves,Coastal Engineering, : -.

. Seelam, J. K. and T. E. Baldock (),Direct bed shear stress measurementsunder solitary tsunami-type wavesand breaking tsunami wavefronts,International Conference on CoastalDynamics, Tokyo, Japan.

. Seelam, J. K. and T. E. Baldock (),Role of submarine canyon on tsunamiamplification on south east coastof India, International Conference of

Asia Oceania Geosciences Society,Singapore, poster presentation.

. Seelam, J. K. and T. E. Baldock (),Measurements and modelling of directbed shear stress under solitary waves, thInternational Conference on Hydro-Scienceand Engineering, Chennai, India, -.

. Seelam, J. K . and T. E. Baldock ().Tsunami induced bed shear strewsseson Northwest Coast of Australia.

International Conference of Asia Oceania

Geosciences Society (AOGS), Taiwan.. Seelam, J. K. and T. E. Baldock ().

Tsunami induced shear stresses alongsubmarine canyons off south-east coast ofIndia. th International Conference on Asiaand Pacific Coasts (APAC), Hong Kong.

. Seelam, J. K. and T. E. Baldock ().Solitary wave friction factors fromdirect shear measurements on a slopingbed. th International Conferenceon Coastal and Port Engineering inDeveloping Countries, Madras, India.

. Seelam, J. K. and T. E. Baldock (),Comparison of bed shear undernon-breaking and breaking solitarywaves, International Journal of Oceanand Climate Systems: (): -.

. Senthilkumar, M., P. Rajeev, P. and J.Kodikara (). Offshore pipe clay-seabed interaction in axial direction.Cluster workshop: abstract.

. Senthilkumar, M., J. Kodikara and P.Rajeev (). Numerical modelling ofundrained vertical load-deformationbehaviour of seabed pipelines.th International Confernce of theInternational Association for ComputerMethods and Advances in Geomechanics(IACMAG ), Melbourne, Australia.

. Senthilkumar, M., J. Kodikara and P.Rajeev (). Numerical modelling ofvertical load-displacement behaviourof offshore pipeline using coupledanalysis. Pan Am CGS GeotechnicalConference, Toronto, Canada.

. Senthilkumar, P. R., M., J. Kodikara andN.I. Thusynathan (). Laboratorymodelling of pipe-clay seabed interactionin axial direction. InternationalSymposium of Offshore and PolarEngineering , Maui, Hawaii.

. Sleelam, J. K., Baldock, T.E. (),Tsunami induced currents in vicinityof Palar submarine canyon off south-east coast of India – a numericalmodel study, Poster presentation atInternational Conference of Asia OceaniaGeosciences Society (AOGS ), India.

. Tian, Y., M.J. Cassidy and G. Gaudin,(), Pipeline integrity: centrifugemodelling of pipes in sand, Geo:.

. Tian, Y., M.J. Cassidy and C. Gaudin(), Advancing pipe-soil interactionmodels through geotechnical centrifugetesting in calcareous sands, AppliedOcean Research, (): -.

. Tian, Y., M.J. Cassidy and B.S. Youssef(). Consideration for on-bottom

stability of unburied pipelines usingforce-resultant models. th InternationalOffshore and Polar Engineering Conference(ISOPE), Beijing, China, : -.


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. Tian, Y., M.J. Cassidy and C. Gaudin(). Centrifuge tests of shallowlyembedded pipeline on undrained andpartially drained silt sand. GEO: .

. Tian, Y., D. Wang and M.J. Cassidy(). Large deformation finite elementanalysis of offshore geotechnicalpenetration tests. nd InternationalSymposium on Computational Mechanics(ComGeo), Cavtat-Dubrovnik, Croatia.

. Tian, Y., M.J. Cassidy and B.S. Youssef(), Consideration for on-bottomstability of unburied pipelines using adynamic fluid-structure-soil simulationprogram, International Journal of Offshoreand Polar Engineering: (): -.

. Tian, Y. and M. J. Cassidy (), Explicitand Implicit integration algorithms foran elastoplastic pipe-soil interactionmacroelement model, th InternationalConference on Offshore Mechanics and

Arctic Engineer ing, OMAE- .

. Tian, Y. and M. J. Cassidy (), Modellingof pipe-soil interaction and its applicationin numerical simulation, International

Journal of Geomechanics , (): -.

. Tian, Y. and M. J. Cassidy (), A pract icalapproach to numerical modelling ofpipe-soil interaction, th InternationalOffshore and Polar Engineering Conference(ISOPE), Vancouver, Canada, :-.

. Tian, Y. and M. J. Cassidy (), Pipe-soil interaction analysis with a D

macroelement model, th InternationalOffshore and Polar Engineering Conference(ISOPE), Osaka, Japan, -.

. Tian, Y. and M. J. Cassidy (), Thechallenge of numerically implementingnumerous force-resultant modelsin the stability analysis of long on-bottom pipelines, Computers andGeotechnics, (-): -.

. Tian, Y. and M. J. Cassidy (), A pipe-soilinteraction model incorporating largelateral displacements in calcareous sand,

Journal of Geotechnical & GeoenvironmentalEngineering, (): -.

. Tian, Y. and M. J. Cassidy, (),Equivalent absolute lateral staticstability of on-bottom offshorepipelines, Australian Geomechanics

Journal, under review November.

. Tian, Y. and M. J. Cassidy (),Incorporating uplift in the analysisof shallowly embedded pipelines:Int. Journal of Structural Engineeringand Mechanics, (): -.

. Tran, D. S. and V. M. Tran ().Propagation of buckle in subsea pipelines,BE Thesis, University of Queensland.

. Wang, D., D.J. White and M.F. Randolph

(), Numerical simulations of dynamicembedment during pipe laying on softclay, th International Conference onOffshore Mechanics and Arctic Engineering,Honolulu, Hawaii, OMAE-.

. Wang, D., D.J. White and M.F. Randolph(), Large deformation finite elementanalysis of pipe penetration and large-amplitude lateral displacement, Canadian

Geotechnical Journal, (): -.. Wang, D., M.F. Randolph and D.J. White

(), A dynamic large deformation finiteelement method and element additiontechnique, International Journal forGeomechanics: under review April .

. Wang, Y., X.Q. Zhu, H. Hao andK.Q. Fan (), Development andtesting of guided wave techniquesfor pipeline integrity monitoring,st Annual Society for UnderwaterSociety Subsea Technical Conference(SUT), Perth, CD:SUT-WangY.

. Westgate, Z., D.J. White and M.F. Randolph(), Video observations of dynamicembedment during pipelaying, thInternational Conference on OffshoreMechanics and Arctic Engineering (OMAE

), Honolulu, Hawaii, OMAE-.

. Westgate, Z., M.F. Randolph, M.F, D.J.White and S. Li (), The influenceof seastate on as laid pipelineembedment: a case study, AppliedOcean Research, (): -.

. Westgate, Z., D.J. White and M.F.Randolph (), Pipeline laying andembedment in soft fine-grained soils: fieldobservations and numerical simulations., Offshore Technology Conference, Houston,

OTC:Paper number .. Westgate, Z. J., M.F. Randolph and D.J.

White (), Theoretical

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