Kenneth Johannessen Eik Ice Management in Arctic Offshore - DiVA

187 Pages·2010·12.5 MB·English

Doctoral theses at NTNU, 2010:2(cid:38)(cid:37)
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ISBN 978-82-471-2402-4 (printed ver.)
ISBN 978-82-471-2403-1 (electronic ver.)
ISSN 1503-8181
Doctoral theses at N NTNUNorwegian University ofScience and TechnologyThesis for the degree ofphilosophiae doctorg Science and Technologynd Transport Engineering
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Kenneth Johannessen Eik Kenneth Johannessen Eik
Ice Management in Arctic Offshore Ice Management in Arctic Offshore
Operations and Field Operations and Field
Developments Developments
Thesis for the degree of philosophiae doctor Thesis for the degree of philosophiae doctor
Trondheim, November 2010 Trondheim, November 2010
Norwegian University of Norwegian University of
Science and Technology Science and Technology
Faculty of Engineering Science and Technology Faculty of Engineering Science and Technology
Department of Civil and Transport Engineering Department of Civil and Transport Engineering
Kenneth Johannessen Eik Kenneth Johannessen Eik
Ice Management in Arctic Offshore Ice Management in Arctic Offshore
Operations and Field Operations and Field
Developments Developments
Thesis for the degree of philosophiae doctor Thesis for the degree of philosophiae doctor
Trondheim, November 2010 Trondheim, November 2010
Norwegian University of Norwegian University of
Science and Technology Science and Technology
Faculty of Engineering Science and Technology Faculty of Engineering Science and Technology
Department of Civil and Transport Engineering Department of Civil and Transport Engineering
NTNU NTNU
Norwegian University of Science and Technology Norwegian University of Science and Technology
Thesis for the degree of philosophiae doctor Thesis for the degree of philosophiae doctor
Faculty of Engineering Science and Technology Faculty of Engineering Science and Technology
Department of Civil and Transport Engineering Department of Civil and Transport Engineering
©Kenneth Johannessen Eik ©Kenneth Johannessen Eik
ISBN 978-82-471-2402-4 (printed ver.) ISBN 978-82-471-2402-4 (printed ver.)
ISBN 978-82-471-2403-1 (electronic ver.) ISBN 978-82-471-2403-1 (electronic ver.)
ISSN 1503-8181 ISSN 1503-8181
Doctoral Theses at NTNU, 2010:210 Doctoral Theses at NTNU, 2010:220
Printed by Tapir Uttrykk Printed by Tapir Uttrykk
NTNU NTNU
Norwegian University of Science and Technology Norwegian University of Science and Technology
Thesis for the degree of philosophiae doctor Thesis for the degree of philosophiae doctor
Faculty of Engineering Science and Technology Faculty of Engineering Science and Technology
Department of Civil and Transport Engineering Department of Civil and Transport Engineering
©Kenneth Johannessen Eik ©Kenneth Johannessen Eik
ISBN 978-82-471-2402-4 (printed ver.) ISBN 978-82-471-2402-4 (printed ver.)
ISBN 978-82-471-2403-1 (electronic ver.) ISBN 978-82-471-2403-1 (electronic ver.)
ISSN 1503-8181 ISSN 1503-8181
Doctoral Theses at NTNU, 2010:220 Doctoral Theses at NTNU, 2010:220
Printed by Tapir Uttrykk Printed by Tapir Uttrykk
i i
ABSTRACT ABSTRACT
The subject ice management has been studied with the main objective to deduce a The subject ice management has been studied with the main objective to deduce a
methodology that incorporates the effect of ice management on the structural reliability methodology that incorporates the effect of ice management on the structural reliability
of offshore installations. This was done by first studying Arctic projects in the past and of offshore installations. This was done by first studying Arctic projects in the past and
summarizes the learning’s. All available reports were unanimous and highlighted ice summarizes the learning’s. All available reports were unanimous and highlighted ice
management as a key for the successes in the projects. Based on the reported management as a key for the successes in the projects. Based on the reported
experiences, an unambiguous definition of ice management was made: experiences, an unambiguous definition of ice management was made:
“Ice management is the sum of all activities where the objective is to reduce or “Ice management is the sum of all activities where the objective is to reduce or
avoid actions from any kind of ice features” avoid actions from any kind of ice features”
Despite the number of similarities between sea ice management and iceberg Despite the number of similarities between sea ice management and iceberg
management, it was decided to study each of the fields individually. The motivation for management, it was decided to study each of the fields individually. The motivation for
doing so was that iceberg management in general focus on reducing the frequency of doing so was that iceberg management in general focus on reducing the frequency of
impacts between icebergs and installations while sea ice management generally focus impacts between icebergs and installations while sea ice management generally focus
on reducing the sizes in the ice floe distributions and thereby reduces the severity of the on reducing the sizes in the ice floe distributions and thereby reduces the severity of the
ice actions. One methodology for including iceberg management and one for including ice actions. One methodology for including iceberg management and one for including
sea ice management in the offshore installation design process has been proposed. sea ice management in the offshore installation design process has been proposed.
In order to develop the models for ice management efficiency a number of studies In order to develop the models for ice management efficiency a number of studies
of the various elements were conducted. Individual papers regarding subsurface ice of the various elements were conducted. Individual papers regarding subsurface ice
intelligence, iceberg drift modelling, iceberg deterioration, iceberg deflection in ice and intelligence, iceberg drift modelling, iceberg deterioration, iceberg deflection in ice and
ice load variability has been published and are included in this thesis. Each of these ice load variability has been published and are included in this thesis. Each of these
papers is of importance for the proposed models for ice management efficiency. papers is of importance for the proposed models for ice management efficiency.
The possibility to disconnect an installation and escape the site has been considered The possibility to disconnect an installation and escape the site has been considered
both in the methodologies for iceberg management and sea ice management. When both in the methodologies for iceberg management and sea ice management. When
considering the number and magnitude of uncertainties both with respect to load considering the number and magnitude of uncertainties both with respect to load
calculations from icebergs and sea ice, it is concluded that disconnection capabilities calculations from icebergs and sea ice, it is concluded that disconnection capabilities
should be considered in all Arctic projects. It was shown that icebreakers not necessarily should be considered in all Arctic projects. It was shown that icebreakers not necessarily
are sufficient to reduce extreme or abnormal loads on a structure. However, there may are sufficient to reduce extreme or abnormal loads on a structure. However, there may
i i
ABSTRACT ABSTRACT
The subject ice management has been studied with the main objective to deduce a The subject ice management has been studied with the main objective to deduce a
methodology that incorporates the effect of ice management on the structural reliability methodology that incorporates the effect of ice management on the structural reliability
of offshore installations. This was done by first studying Arctic projects in the past and of offshore installations. This was done by first studying Arctic projects in the past and
summarizes the learning’s. All available reports were unanimous and highlighted ice summarizes the learning’s. All available reports were unanimous and highlighted ice
management as a key for the successes in the projects. Based on the reported management as a key for the successes in the projects. Based on the reported
experiences, an unambiguous definition of ice management was made: experiences, an unambiguous definition of ice management was made:
“Ice management is the sum of all activities where the objective is to reduce or “Ice management is the sum of all activities where the objective is to reduce or
avoid actions from any kind of ice features” avoid actions from any kind of ice features”
Despite the number of similarities between sea ice management and iceberg Despite the number of similarities between sea ice management and iceberg
management, it was decided to study each of the fields individually. The motivation for management, it was decided to study each of the fields individually. The motivation for
doing so was that iceberg management in general focus on reducing the frequency of doing so was that iceberg management in general focus on reducing the frequency of
impacts between icebergs and installations while sea ice management generally focus impacts between icebergs and installations while sea ice management generally focus
on reducing the sizes in the ice floe distributions and thereby reduces the severity of the on reducing the sizes in the ice floe distributions and thereby reduces the severity of the
ice actions. One methodology for including iceberg management and one for including ice actions. One methodology for including iceberg management and one for including
sea ice management in the offshore installation design process has been proposed. sea ice management in the offshore installation design process has been proposed.
In order to develop the models for ice management efficiency a number of studies In order to develop the models for ice management efficiency a number of studies
of the various elements were conducted. Individual papers regarding subsurface ice of the various elements were conducted. Individual papers regarding subsurface ice
intelligence, iceberg drift modelling, iceberg deterioration, iceberg deflection in ice and intelligence, iceberg drift modelling, iceberg deterioration, iceberg deflection in ice and
ice load variability has been published and are included in this thesis. Each of these ice load variability has been published and are included in this thesis. Each of these
papers is of importance for the proposed models for ice management efficiency. papers is of importance for the proposed models for ice management efficiency.
The possibility to disconnect an installation and escape the site has been considered The possibility to disconnect an installation and escape the site has been considered
both in the methodologies for iceberg management and sea ice management. When both in the methodologies for iceberg management and sea ice management. When
considering the number and magnitude of uncertainties both with respect to load considering the number and magnitude of uncertainties both with respect to load
calculations from icebergs and sea ice, it is concluded that disconnection capabilities calculations from icebergs and sea ice, it is concluded that disconnection capabilities
should be considered in all Arctic projects. It was shown that icebreakers not necessarily should be considered in all Arctic projects. It was shown that icebreakers not necessarily
are sufficient to reduce extreme or abnormal loads on a structure. However, there may are sufficient to reduce extreme or abnormal loads on a structure. However, there may
ii ii
still be a number of reasons for why icebreakers also should be considered in Arctic still be a number of reasons for why icebreakers also should be considered in Arctic
projects. projects.
The methodologies presented in this work provide adequate tools for evaluating the The methodologies presented in this work provide adequate tools for evaluating the
effect of various icebreaker fleets and iceberg management systems. However, the effect of various icebreaker fleets and iceberg management systems. However, the
approaches rely on a number of tools and formulations with inherent weaknesses and approaches rely on a number of tools and formulations with inherent weaknesses and
advantages. The weaknesses are discussed and recommendations for further work in advantages. The weaknesses are discussed and recommendations for further work in
order to improve the models have been proposed. order to improve the models have been proposed.
ii ii
still be a number of reasons for why icebreakers also should be considered in Arctic still be a number of reasons for why icebreakers also should be considered in Arctic
projects. projects.
The methodologies presented in this work provide adequate tools for evaluating the The methodologies presented in this work provide adequate tools for evaluating the
effect of various icebreaker fleets and iceberg management systems. However, the effect of various icebreaker fleets and iceberg management systems. However, the
approaches rely on a number of tools and formulations with inherent weaknesses and approaches rely on a number of tools and formulations with inherent weaknesses and
advantages. The weaknesses are discussed and recommendations for further work in advantages. The weaknesses are discussed and recommendations for further work in
order to improve the models have been proposed. order to improve the models have been proposed.
iii iii
ACKNOWLEDGEMENTS ACKNOWLEDGEMENTS
The main motivation for writing a thesis on the subject “Ice Management” was The main motivation for writing a thesis on the subject “Ice Management” was
based on the acknowledgement that future offshore developments will take place in based on the acknowledgement that future offshore developments will take place in
Arctic environments and that this introduces a number of new challenges for the Arctic environments and that this introduces a number of new challenges for the
offshore industry. Personally, I had a strong motivation for being a part of these future offshore industry. Personally, I had a strong motivation for being a part of these future
projects and being able to contribute technically. When my colleague and later co- projects and being able to contribute technically. When my colleague and later co-
supervisor, Ove Tobias Gudmestad took the initiative to start a PhD on the subject, I supervisor, Ove Tobias Gudmestad took the initiative to start a PhD on the subject, I
was please to volunteer for the “mission”. Almost four years later, I can look back on a was please to volunteer for the “mission”. Almost four years later, I can look back on a
hectic but joyful time both with respect to work and private life. There are a number of hectic but joyful time both with respect to work and private life. There are a number of
persons I would like to express my gratitude to, for making it possible for me to persons I would like to express my gratitude to, for making it possible for me to
undertake this work. undertake this work.
First, I would like to thank my employer, Statoil, for having faith in me and letting First, I would like to thank my employer, Statoil, for having faith in me and letting
me do this study as a part of my work. The former chief researcher Arnt Olufsen me do this study as a part of my work. The former chief researcher Arnt Olufsen
supported the idea about doing a PhD in order to increase my competence. Ove Tobias supported the idea about doing a PhD in order to increase my competence. Ove Tobias
Gudmestad, Einar Nygaard , Arne Gürtner and Hanne Greiff Johnsen ensured at Gudmestad, Einar Nygaard , Arne Gürtner and Hanne Greiff Johnsen ensured at
different stages that funding were available to do the study. Our chief researcher Finn different stages that funding were available to do the study. Our chief researcher Finn
Gunnar Nielsen has been of great support by carefully reading my papers and Gunnar Nielsen has been of great support by carefully reading my papers and
contributing with constructive comments. contributing with constructive comments.
The unique milieu in the “PhD basement” at NTNU should be praised for being The unique milieu in the “PhD basement” at NTNU should be praised for being
open, incorporating and a source for exchange of knowledge within a number of fields. open, incorporating and a source for exchange of knowledge within a number of fields.
We have an always enthusiastic supervisor in Professor Sveinung Løset which are full We have an always enthusiastic supervisor in Professor Sveinung Løset which are full
of new ideas and is able to make things happen. Amongst the PhD students I would like of new ideas and is able to make things happen. Amongst the PhD students I would like
to emphasize my appreciation of Raed Lubbad, Nicolas Serre, Vegard Aksnes, Oddgeir to emphasize my appreciation of Raed Lubbad, Nicolas Serre, Vegard Aksnes, Oddgeir
Dalane, Christian Lønøy, Marit Reiso, Ada Repetto-Llamazares, Felix Breitschädel, Dalane, Christian Lønøy, Marit Reiso, Ada Repetto-Llamazares, Felix Breitschädel,
Wolfgang Kampel, Sergiy Sukhorukov, Anton Kulyakthin, Haiyan Long, Kim Wolfgang Kampel, Sergiy Sukhorukov, Anton Kulyakthin, Haiyan Long, Kim
Yangkyun and (now colleague in Statoil) Arne Gürtner. Further the post docs. Jenny Yangkyun and (now colleague in Statoil) Arne Gürtner. Further the post docs. Jenny
Trumar, Alex Klein-Paste, Paul Thomassen, professors Knut Høyland and Alf Tørum Trumar, Alex Klein-Paste, Paul Thomassen, professors Knut Høyland and Alf Tørum
and our administrator Marion Beentjes all contributes to the good and friendly and our administrator Marion Beentjes all contributes to the good and friendly
environment in the basement. environment in the basement.
iii iii
ACKNOWLEDGEMENTS ACKNOWLEDGEMENTS
The main motivation for writing a thesis on the subject “Ice Management” was The main motivation for writing a thesis on the subject “Ice Management” was
based on the acknowledgement that future offshore developments will take place in based on the acknowledgement that future offshore developments will take place in
Arctic environments and that this introduces a number of new challenges for the Arctic environments and that this introduces a number of new challenges for the
offshore industry. Personally, I had a strong motivation for being a part of these future offshore industry. Personally, I had a strong motivation for being a part of these future
projects and being able to contribute technically. When my colleague and later co- projects and being able to contribute technically. When my colleague and later co-
supervisor, Ove Tobias Gudmestad took the initiative to start a PhD on the subject, I supervisor, Ove Tobias Gudmestad took the initiative to start a PhD on the subject, I
was please to volunteer for the “mission”. Almost four years later, I can look back on a was please to volunteer for the “mission”. Almost four years later, I can look back on a
hectic but joyful time both with respect to work and private life. There are a number of hectic but joyful time both with respect to work and private life. There are a number of
persons I would like to express my gratitude to, for making it possible for me to persons I would like to express my gratitude to, for making it possible for me to
undertake this work. undertake this work.
First, I would like to thank my employer, Statoil, for having faith in me and letting First, I would like to thank my employer, Statoil, for having faith in me and letting
me do this study as a part of my work. The former chief researcher Arnt Olufsen me do this study as a part of my work. The former chief researcher Arnt Olufsen
supported the idea about doing a PhD in order to increase my competence. Ove Tobias supported the idea about doing a PhD in order to increase my competence. Ove Tobias
Gudmestad, Einar Nygaard , Arne Gürtner and Hanne Greiff Johnsen ensured at Gudmestad, Einar Nygaard , Arne Gürtner and Hanne Greiff Johnsen ensured at
different stages that funding were available to do the study. Our chief researcher Finn different stages that funding were available to do the study. Our chief researcher Finn
Gunnar Nielsen has been of great support by carefully reading my papers and Gunnar Nielsen has been of great support by carefully reading my papers and
contributing with constructive comments. contributing with constructive comments.
The unique milieu in the “PhD basement” at NTNU should be praised for being The unique milieu in the “PhD basement” at NTNU should be praised for being
open, incorporating and a source for exchange of knowledge within a number of fields. open, incorporating and a source for exchange of knowledge within a number of fields.
We have an always enthusiastic supervisor in Professor Sveinung Løset which are full We have an always enthusiastic supervisor in Professor Sveinung Løset which are full
of new ideas and is able to make things happen. Amongst the PhD students I would like of new ideas and is able to make things happen. Amongst the PhD students I would like
to emphasize my appreciation of Raed Lubbad, Nicolas Serre, Vegard Aksnes, Oddgeir to emphasize my appreciation of Raed Lubbad, Nicolas Serre, Vegard Aksnes, Oddgeir
Dalane, Christian Lønøy, Marit Reiso, Ada Repetto-Llamazares, Felix Breitschädel, Dalane, Christian Lønøy, Marit Reiso, Ada Repetto-Llamazares, Felix Breitschädel,
Wolfgang Kampel, Sergiy Sukhorukov, Anton Kulyakthin, Haiyan Long, Kim Wolfgang Kampel, Sergiy Sukhorukov, Anton Kulyakthin, Haiyan Long, Kim
Yangkyun and (now colleague in Statoil) Arne Gürtner. Further the post docs. Jenny Yangkyun and (now colleague in Statoil) Arne Gürtner. Further the post docs. Jenny
Trumar, Alex Klein-Paste, Paul Thomassen, professors Knut Høyland and Alf Tørum Trumar, Alex Klein-Paste, Paul Thomassen, professors Knut Høyland and Alf Tørum
and our administrator Marion Beentjes all contributes to the good and friendly and our administrator Marion Beentjes all contributes to the good and friendly
environment in the basement. environment in the basement.
iv iv
The work with a PhD study may sometimes be considered as lonely as you are the The work with a PhD study may sometimes be considered as lonely as you are the
one and only responsible for the progress. I have been able to enjoy the work from the one and only responsible for the progress. I have been able to enjoy the work from the
start to the end and never experienced the phase where I get bored of the subject. This is start to the end and never experienced the phase where I get bored of the subject. This is
thanks to my wife Nina Elise, and my sons Vegard, Sondre and Håvard which always thanks to my wife Nina Elise, and my sons Vegard, Sondre and Håvard which always
brings me back to the reality and ensures that I have the right perspectives in life. brings me back to the reality and ensures that I have the right perspectives in life.
iv iv
The work with a PhD study may sometimes be considered as lonely as you are the The work with a PhD study may sometimes be considered as lonely as you are the
one and only responsible for the progress. I have been able to enjoy the work from the one and only responsible for the progress. I have been able to enjoy the work from the
start to the end and never experienced the phase where I get bored of the subject. This is start to the end and never experienced the phase where I get bored of the subject. This is
thanks to my wife Nina Elise, and my sons Vegard, Sondre and Håvard which always thanks to my wife Nina Elise, and my sons Vegard, Sondre and Håvard which always
brings me back to the reality and ensures that I have the right perspectives in life. brings me back to the reality and ensures that I have the right perspectives in life.
v v
CONTENTS CONTENTS
1 INTRODUCTION......................................................................................................................1 1 INTRODUCTION......................................................................................................................1
1.1 General....................................................................................................................................1 1.1 General....................................................................................................................................1
1.2 Scope and organisation of the thesis......................................................................................2 1.2 Scope and organisation of the thesis......................................................................................2
1.3 Readership...............................................................................................................................3 1.3 Readership...............................................................................................................................3
2 REVIEW OF EXPERIENCES WITHIN ICE AND ICEBERG MANAGEMENT..........6 2 REVIEW OF EXPERIENCES WITHIN ICE AND ICEBERG MANAGEMENT..........6
3 ICE INTELLIGENCE.............................................................................................................24 3 ICE INTELLIGENCE.............................................................................................................24
3.1 General..................................................................................................................................24 3.1 General..................................................................................................................................24
3.2 Specifications for a subsurface ice intelligence system........................................................26 3.2 Specifications for a subsurface ice intelligence system........................................................26
4 EFFICIENCY OF ICEBERG MANAGEMENT.................................................................36 4 EFFICIENCY OF ICEBERG MANAGEMENT.................................................................36
4.1 Iceberg drift...........................................................................................................................36 4.1 Iceberg drift...........................................................................................................................36
4.2 Iceberg deterioration.............................................................................................................86 4.2 Iceberg deterioration.............................................................................................................86
4.3 Physical iceberg management.............................................................................................104 4.3 Physical iceberg management.............................................................................................104
4.4 Iceberg management and impact on design of offshore structures....................................132 4.4 Iceberg management and impact on design of offshore structures....................................132
5 EFFICIENCY OF SEA ICE MANAGEMENT..................................................................148 5 EFFICIENCY OF SEA ICE MANAGEMENT..................................................................148
5.1 Ice load formulations...........................................................................................................148 5.1 Ice load formulations...........................................................................................................148
5.2 Ice load variability..............................................................................................................150 5.2 Ice load variability..............................................................................................................150
5.3 Sea ice management and impact on design of offshore structures....................................166 5.3 Sea ice management and impact on design of offshore structures....................................166
6 SUMMARY.............................................................................................................................208 6 SUMMARY.............................................................................................................................208
6.1 Summary and conclusions...................................................................................................208 6.1 Summary and conclusions...................................................................................................208
6.2 Recommendations for further work.....................................................................................212 6.2 Recommendations for further work.....................................................................................212
7 REFERENCES.......................................................................................................................213 7 REFERENCES.......................................................................................................................213
v v
CONTENTS CONTENTS
1 INTRODUCTION......................................................................................................................1 1 INTRODUCTION......................................................................................................................1
1.1 General....................................................................................................................................1 1.1 General....................................................................................................................................1
1.2 Scope and organisation of the thesis......................................................................................2 1.2 Scope and organisation of the thesis......................................................................................2
1.3 Readership...............................................................................................................................3 1.3 Readership...............................................................................................................................3
2 REVIEW OF EXPERIENCES WITHIN ICE AND ICEBERG MANAGEMENT..........6 2 REVIEW OF EXPERIENCES WITHIN ICE AND ICEBERG MANAGEMENT..........6
3 ICE INTELLIGENCE.............................................................................................................24 3 ICE INTELLIGENCE.............................................................................................................24
3.1 General..................................................................................................................................24 3.1 General..................................................................................................................................24
3.2 Specifications for a subsurface ice intelligence system........................................................26 3.2 Specifications for a subsurface ice intelligence system........................................................26
4 EFFICIENCY OF ICEBERG MANAGEMENT.................................................................36 4 EFFICIENCY OF ICEBERG MANAGEMENT.................................................................36
4.1 Iceberg drift...........................................................................................................................36 4.1 Iceberg drift...........................................................................................................................36
4.2 Iceberg deterioration.............................................................................................................86 4.2 Iceberg deterioration.............................................................................................................86
4.3 Physical iceberg management.............................................................................................104 4.3 Physical iceberg management.............................................................................................104
4.4 Iceberg management and impact on design of offshore structures....................................132 4.4 Iceberg management and impact on design of offshore structures....................................132
5 EFFICIENCY OF SEA ICE MANAGEMENT..................................................................148 5 EFFICIENCY OF SEA ICE MANAGEMENT..................................................................148
5.1 Ice load formulations...........................................................................................................148 5.1 Ice load formulations...........................................................................................................148
5.2 Ice load variability..............................................................................................................150 5.2 Ice load variability..............................................................................................................150
5.3 Sea ice management and impact on design of offshore structures....................................166 5.3 Sea ice management and impact on design of offshore structures....................................166
6 SUMMARY.............................................................................................................................208 6 SUMMARY.............................................................................................................................208
6.1 Summary and conclusions...................................................................................................208 6.1 Summary and conclusions...................................................................................................208
6.2 Recommendations for further work.....................................................................................212 6.2 Recommendations for further work.....................................................................................212
7 REFERENCES.......................................................................................................................213 7 REFERENCES.......................................................................................................................213
1 1

1 INTRODUCTION 1 INTRODUCTION
1.1 General 1.1 General
In order to supply the world with sufficient hydrocarbons, the petroleum industry is In order to supply the world with sufficient hydrocarbons, the petroleum industry is
expected to initiate an increasing number of offshore developments in Arctic waters. expected to initiate an increasing number of offshore developments in Arctic waters.
This introduces new challenges with respect to design philosophy as the standards This introduces new challenges with respect to design philosophy as the standards
established for open water developments may not be optimal for developments in ice established for open water developments may not be optimal for developments in ice
covered waters or waters exposed to icebergs. covered waters or waters exposed to icebergs.
There is a number of reasons for why the open water philosophies for offshore There is a number of reasons for why the open water philosophies for offshore
installation design may be insufficient in ice covered waters. In this respect, installation design may be insufficient in ice covered waters. In this respect,
uncertainties in ice and iceberg load calculations should be mentioned. Furthermore, uncertainties in ice and iceberg load calculations should be mentioned. Furthermore,
significant uncertainties in available environmental data in most Arctic regions must be significant uncertainties in available environmental data in most Arctic regions must be
expected as such data are both expensive and complicated to collect. The challenges in expected as such data are both expensive and complicated to collect. The challenges in
ice load calculations and ice data collection calls for innovative thinking in the design ice load calculations and ice data collection calls for innovative thinking in the design
process. process.
In spite of the increased uncertainties in Arctic projects, there are possibilities to In spite of the increased uncertainties in Arctic projects, there are possibilities to
include load reducing measures and thereby increase the overall safety. Examples of include load reducing measures and thereby increase the overall safety. Examples of
such measures may be use of icebreakers in ice covered waters or supply vessels for such measures may be use of icebreakers in ice covered waters or supply vessels for
iceberg towing. Furthermore, if the offshore installations are designed with the iceberg towing. Furthermore, if the offshore installations are designed with the
possibility to disconnect and escape their site, an additional level of safety may be possibility to disconnect and escape their site, an additional level of safety may be
achieved. All means contributing to avoiding or reducing ice loads may be incorporated achieved. All means contributing to avoiding or reducing ice loads may be incorporated
in the designation “Ice management”. The present work focuses on the elements in sea in the designation “Ice management”. The present work focuses on the elements in sea
ice and iceberg management with the objective of proposing approaches for how to ice and iceberg management with the objective of proposing approaches for how to
include these elements in the offshore installation design process. include these elements in the offshore installation design process.
1 1

1 INTRODUCTION 1 INTRODUCTION
1.1 General 1.1 General
In order to supply the world with sufficient hydrocarbons, the petroleum industry is In order to supply the world with sufficient hydrocarbons, the petroleum industry is
expected to initiate an increasing number of offshore developments in Arctic waters. expected to initiate an increasing number of offshore developments in Arctic waters.
This introduces new challenges with respect to design philosophy as the standards This introduces new challenges with respect to design philosophy as the standards
established for open water developments may not be optimal for developments in ice established for open water developments may not be optimal for developments in ice
covered waters or waters exposed to icebergs. covered waters or waters exposed to icebergs.
There is a number of reasons for why the open water philosophies for offshore There is a number of reasons for why the open water philosophies for offshore
installation design may be insufficient in ice covered waters. In this respect, installation design may be insufficient in ice covered waters. In this respect,
uncertainties in ice and iceberg load calculations should be mentioned. Furthermore, uncertainties in ice and iceberg load calculations should be mentioned. Furthermore,
significant uncertainties in available environmental data in most Arctic regions must be significant uncertainties in available environmental data in most Arctic regions must be
expected as such data are both expensive and complicated to collect. The challenges in expected as such data are both expensive and complicated to collect. The challenges in
ice load calculations and ice data collection calls for innovative thinking in the design ice load calculations and ice data collection calls for innovative thinking in the design
process. process.
In spite of the increased uncertainties in Arctic projects, there are possibilities to In spite of the increased uncertainties in Arctic projects, there are possibilities to
include load reducing measures and thereby increase the overall safety. Examples of include load reducing measures and thereby increase the overall safety. Examples of
such measures may be use of icebreakers in ice covered waters or supply vessels for such measures may be use of icebreakers in ice covered waters or supply vessels for
iceberg towing. Furthermore, if the offshore installations are designed with the iceberg towing. Furthermore, if the offshore installations are designed with the
possibility to disconnect and escape their site, an additional level of safety may be possibility to disconnect and escape their site, an additional level of safety may be
achieved. All means contributing to avoiding or reducing ice loads may be incorporated achieved. All means contributing to avoiding or reducing ice loads may be incorporated
in the designation “Ice management”. The present work focuses on the elements in sea in the designation “Ice management”. The present work focuses on the elements in sea
ice and iceberg management with the objective of proposing approaches for how to ice and iceberg management with the objective of proposing approaches for how to
include these elements in the offshore installation design process. include these elements in the offshore installation design process.
2 2

1.2 Scope and organisation of the thesis 1.2 Scope and organisation of the thesis
The intent of this thesis is to gain increased knowledge about ice management in The intent of this thesis is to gain increased knowledge about ice management in
general and to transfer the knowledge from practical experiences into statistical design general and to transfer the knowledge from practical experiences into statistical design
frameworks in particular. frameworks in particular.
The work is presented through nine papers each dealing with different elements of The work is presented through nine papers each dealing with different elements of
ice management. All papers except one have been published in international journals ice management. All papers except one have been published in international journals
and conference proceedings. The last paper is presently pending on a journal review. and conference proceedings. The last paper is presently pending on a journal review.
The first paper, “Review of experiences within ice and iceberg management”, which is The first paper, “Review of experiences within ice and iceberg management”, which is
presented in Chapter 2, provides a proper introduction to the special field “ice presented in Chapter 2, provides a proper introduction to the special field “ice
management”. An unambiguous definition of ice management is proposed and lessons management”. An unambiguous definition of ice management is proposed and lessons
learned from all relevant Arctic projects are highlighted. learned from all relevant Arctic projects are highlighted.
In order to include ice management in statistical frameworks for design In order to include ice management in statistical frameworks for design
calculations, a number of building blocks need to be in place. Examples of such calculations, a number of building blocks need to be in place. Examples of such
building blocks may be; “ice detection models”, “ice and iceberg drift forecasting building blocks may be; “ice detection models”, “ice and iceberg drift forecasting
models”, “models for calculations of managed ice” and “models for iceberg deflection models”, “models for calculations of managed ice” and “models for iceberg deflection
success”. In order to prepare all the building bricks for real Arctic offshore projects a success”. In order to prepare all the building bricks for real Arctic offshore projects a
substantial amount of work from a number of disciplines will be required. Obviously, it substantial amount of work from a number of disciplines will be required. Obviously, it
is not possible even within the scope of a PhD study to go into detail in all the sub- is not possible even within the scope of a PhD study to go into detail in all the sub-
topics which fall under the special field “ice management”. Consequently, some topics which fall under the special field “ice management”. Consequently, some
selected fields are presented into detail through different papers while others are briefly selected fields are presented into detail through different papers while others are briefly
described. In order to avoid duplicating information, references are made to Chapter 2 described. In order to avoid duplicating information, references are made to Chapter 2
regarding general ice management subjects that are not treated in specific papers. regarding general ice management subjects that are not treated in specific papers.
With respect to ice intelligence (Chapter 1), which is the first activity required in ice With respect to ice intelligence (Chapter 1), which is the first activity required in ice
management operations, it was decided to look closer at the ability to detect ice features management operations, it was decided to look closer at the ability to detect ice features
from the bottom side. Reasons for this was that novel technology such as AUVs and from the bottom side. Reasons for this was that novel technology such as AUVs and
multi beam echo sounders is considered promising with respect to future ice multi beam echo sounders is considered promising with respect to future ice
management operations while more traditional intelligence means such as marine radars management operations while more traditional intelligence means such as marine radars
and satellites already have been considered for most ice management operations. and satellites already have been considered for most ice management operations.
2 2

1.2 Scope and organisation of the thesis 1.2 Scope and organisation of the thesis
The intent of this thesis is to gain increased knowledge about ice management in The intent of this thesis is to gain increased knowledge about ice management in
general and to transfer the knowledge from practical experiences into statistical design general and to transfer the knowledge from practical experiences into statistical design
frameworks in particular. frameworks in particular.
The work is presented through nine papers each dealing with different elements of The work is presented through nine papers each dealing with different elements of
ice management. All papers except one have been published in international journals ice management. All papers except one have been published in international journals
and conference proceedings. The last paper is presently pending on a journal review. and conference proceedings. The last paper is presently pending on a journal review.
The first paper, “Review of experiences within ice and iceberg management”, which is The first paper, “Review of experiences within ice and iceberg management”, which is
presented in Chapter 2, provides a proper introduction to the special field “ice presented in Chapter 2, provides a proper introduction to the special field “ice
management”. An unambiguous definition of ice management is proposed and lessons management”. An unambiguous definition of ice management is proposed and lessons
learned from all relevant Arctic projects are highlighted. learned from all relevant Arctic projects are highlighted.
In order to include ice management in statistical frameworks for design In order to include ice management in statistical frameworks for design
calculations, a number of building blocks need to be in place. Examples of such calculations, a number of building blocks need to be in place. Examples of such
building blocks may be; “ice detection models”, “ice and iceberg drift forecasting building blocks may be; “ice detection models”, “ice and iceberg drift forecasting
models”, “models for calculations of managed ice” and “models for iceberg deflection models”, “models for calculations of managed ice” and “models for iceberg deflection
success”. In order to prepare all the building bricks for real Arctic offshore projects a success”. In order to prepare all the building bricks for real Arctic offshore projects a
substantial amount of work from a number of disciplines will be required. Obviously, it substantial amount of work from a number of disciplines will be required. Obviously, it
is not possible even within the scope of a PhD study to go into detail in all the sub- is not possible even within the scope of a PhD study to go into detail in all the sub-
topics which fall under the special field “ice management”. Consequently, some topics which fall under the special field “ice management”. Consequently, some
selected fields are presented into detail through different papers while others are briefly selected fields are presented into detail through different papers while others are briefly
described. In order to avoid duplicating information, references are made to Chapter 2 described. In order to avoid duplicating information, references are made to Chapter 2
regarding general ice management subjects that are not treated in specific papers. regarding general ice management subjects that are not treated in specific papers.
With respect to ice intelligence (Chapter 1), which is the first activity required in ice With respect to ice intelligence (Chapter 1), which is the first activity required in ice
management operations, it was decided to look closer at the ability to detect ice features management operations, it was decided to look closer at the ability to detect ice features
from the bottom side. Reasons for this was that novel technology such as AUVs and from the bottom side. Reasons for this was that novel technology such as AUVs and
multi beam echo sounders is considered promising with respect to future ice multi beam echo sounders is considered promising with respect to future ice
management operations while more traditional intelligence means such as marine radars management operations while more traditional intelligence means such as marine radars
and satellites already have been considered for most ice management operations. and satellites already have been considered for most ice management operations.