Dissertations / Theses on the topic 'Offshore environment'

A three dimensional computational model of a full scale axial flow tidal turbine has been used to investigate the effects of a range of realistic environmental conditions on turbine performance. The model, which is based on the Reynolds averaged Navier-Stokes equations, has been developed using the commercial flow solver ANSYS Fluent. A 1:30 scale tidal turbine is simulated in an open channel for comparison to existing experimental data. The rotor blades are directly resolved using a body-fitted, unstructured computational grid. Rotor motion is enabled through a sliding mesh interface between the rotor and the channel boundaries. Reasonably good agreement in thrust and power is observed. The computed performance curves are offset from the measured performance curves by a small increment in rotor speed. Subsequently, a full scale axial flow turbine is modelled in a variety of conditions representative of tidal channel flows. A parametric study is carried out to investigate the effects of flow shear, confinement and alignment on turbine performance, structural loading, and wake recovery. Mean power and thrust are found to be higher in sheared flow, relative to uniform flow of equivalent volumetric flow rate. Large fluctuations in blade thrust and torque occur in sheared flow as the blade passes through the high velocity freestream flow in the upper portion of the profile and the lower velocity flow near the channel bed. A stronger shear layer is formed around the upper portion of the wake in sheared flow, leading to enhanced wake mixing. Mean power and thrust are reduced when the turbine is simulated at a lower position in a sheared velocity profile. However, fluctuations in blade loading are increased due to the higher velocity gradient. The opposite effects are observed when the turbine operates at greater heights in sheared flow. Flow misalignment has a negative impact on mean rotor thrust and power, as well as on unsteady blade loading. Although the range of unsteady loading is not increased significantly, additional perturbations are introduced due to interactions between the blade and the nacelle. A deforming surface is introduced using the volume-of-fluid method. Linear wave theory is combined with the existing free surface model to develop an unsteady inflow boundary condition prescribing combined sheared flow and free surface waves. The relative effects of the sheared profile and wave-induced velocities on turbine loading are identified through frequency analysis. Rotor and blade load fluctuations are found to increase with wave height and wave length. In a separate study, the performance of bi-directional ducted tidal turbines is investigated through a parametric study of a range of duct profiles. A two dimensional axi-symmetric computational model is developed to compare the ducted geometries with an unducted device under consistent blockage conditions. The best-performing ducted device achieves a peak power coefficient of approximately 45% of that of the unducted device. Comparisons of streamtube area, velocity and pressure for the flow through the ducted device shows that the duct limits the pressure drop across the rotor and the mass flow through the rotor, resulting in lower device power.

Includes bibliographical references.
The extraction of mineral resources from deep ocean waters has been made possible by the development of large compliant offshore structures. Mooring cables are crucial components in these offshore facilities and form the basis of this study. The aims of this thesis are: to provide a comprehensive review on all aspects of cables, to determine criteria for numerical modelling, and to ascertain the capabilities of the finite element method for cable analyses using the F.E. package ABAQUS. Difficulties associated with large sag cables arise as a result of their inherent flexibility which causes ill-conditioning of the stiffness matrices. Furthermore, the cable winding configuration causes a nonlinear stress-strain relationship, it's sagged geometry results in nonlinear strain-displacement relations, and the immersion in water leads to nonlinear fluid loadings arising from Morison's Equation as well as uncertainties in the fluid parameters. Various models, starting with the developed. Convergence difficulties basic catenary, have been at start-up, caused by a lack of stiffness in the transverse direction, are avoided by supporting the cable when applying loads. It is further established that numerical analyses of flexible structures are most stable in dynamic analyses and when under tension. In general both displacement based isoparametric and hybrid beam elements were found to be more reliable and applicable than truss elements. Cable whip, ocean floor contact and harmonic motions of cables were analysed. Finally a cable/tower interaction was modelled and subjected to a Stokes's wave. Conclusions and guidelines are presented based on the numerical experiments carried out in this study.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
Os sistemas de produção de petróleo em águas profundas, incluindo as unidades flutuantes de produção (plataformas ou navios) e todos os equipamentos que participam da produção são atualmente projetados por complexos sistemas de modelagem computacional. Tais sistemas envolvem as áreas de cálculo estrutural, meteo-oceanografia (forças de correntes, ondas e ventos), hidrodinâmica, risers (tubos de aço rígidos ou flexíveis para levar o óleo do poço em sub-superfície até a unidade de produção), sistemas de ancoragem, equipamentos submarinos, fundações e avaliação de risco geológico-geotécnico. O projeto de uma nova unidade de produção é um processo longo e custoso, podendo durar anos e consumir centenas de milhões de dólares, dependendo da complexidade da unidade e da maturidade da tecnologia desenvolvida para tornar o projeto econômica e tecnicamente viável. Os projetos são conduzidos por diversos especialistas, por vezes geograficamente dispersos, gerando artefatos e resultados independentes, porém altamente inter-relacionados. A necessidade de colaboração é uma característica inerente aos projetos de unidades flutuantes de produção para águas profundas. A possibilidade de compartilhar informações entre usuários, controlar a execução de diferentes ferramentas de modelagem, visualizar e manipular modelos 3D virtuais em ambientes imersivos de Realidade Virtual vem empurrando os limites das atividades dos times na indústria do petróleo especialmente em Engenharia de Petróleo. O objetivo desta tese é o de fundamentar os princípios e equacionar os principais problemas para o desenvolvimento de um Ambiente Colaborativo para Engenharia, denominado CEE (Collaborative Engineering Environment), de forma a permitir a visualização colaborativa e interpretação dos resultados de simulações criadas nos projetos de engenharia, que em geral envolvem também diferentes especialidades. Devido à característica multidisciplinar dos projetos, a visualização colaborativa torna-se um componente de fundamental importância durante o ciclo de vida de projetos de engenharia, especialmente os da área de Engenharia Offshore, utilizada neste trabalho como caso de estudo. Propomos um ambiente integrado para visualização colaborativa a ser usado pelas equipes de engenheiros projetistas durante a execução e controle de projetos de engenharia complexos como é o caso dos projetos de unidades flutuantes de produção para águas profundas. Os requisitos do sistema foram levantados com o objetivo de permitir uma colaboração efetiva entre os participantes, criando um ambiente propício para discussão, validação, interpretação e documentação dos resultados das simulações executadas durante as fases de um projeto de engenharia. Para aumentar ainda mais a capacidade de interpretação e uma melhor compreensão dos resultados o suporte a visualização em ambientes imersivos 3D também esta disponibilizado na ferramenta de visualização utilizada, que foi especialmente adaptada para a área de Engenharia Offhore. Para atingir estes objetivos, propomos uma Arquitetura Orientada a Serviços para o CEE. Esta arquitetura é composta pela integração de diferentes tecnologias de Trabalho Colaborativo Auxiliado por Computador (CSCW), Realidade Virtual e Computação em Grade. Utiliza-se um sistema de Gerência de Workflows de Experimentos Científicos (ScWfMS), baseado em BPEL (Business Process Execution Language), para execução de simulações de engenharia em uma infra-estrutura de computação em grade subjacente e um sistema de Videoconferência (VCS) para suporte a colaboração de áudio e vídeo. Para a visualização dos resultados um sistema de visualização, especializado para Engenharia Offshore, ENVIRON, foi desenvolvido em conjunto com a equipe da PUC-Rio/TecGraf.
Deep-water production systems, including floating production units (platforms or ships) and all the equipments playing a part in the production process, are currently designed by means of complex computational modeling systems. Those systems involve the areas of structural calculus, meteo-oceanography (currents, waves and wind forces), hydrodynamics, risers (rigid or flexible steel pipes for carrying oil from the well in subsurface up to the production unit), mooring systems, submarine equipment, seabed foundations and Geologic/Geotechnical risk assessment. The project of a new production unit is a lengthy and expensive process, that can last many years and consume hundreds of million of dollars, depending on the complexity of the unit and how mature is the technology developed to make the project technically and economically feasible. Projects are conducted by diverse specialists, sometimes geographically distributed, yielding independent but highly interrelated artifacts and results. The need for collaboration is an inherent characteristic of deep-water floating production unit projects. The possibility to share information among users, control the execution of different modeling tools, visualize and manipulate virtual 3D models in immersive Virtual Reality (VR) environments is pushing the limits of teamwork activities in oil and gas industry especially in Offshore Engineering. The objective of this thesis is to establish the fundamental principles and address the main issues in the development of a Collaborative Environment for Engineering, named CEE (Collaborative Engineering Environment), in order to allow the collaborative visualization and interpretation of simulation results produced in engineering projects, which in general also involve different specialties. Due to the multidisciplinary characteristic of those projects, collaborative visualization becomes a key component during the life cycle of engineering projects, especially those in Offshore Engineering, used in this work as case of study. We propose an integrated collaborative environment to be used by project engineers teams during the execution and control of complex engineering projects, as is the case of the projects of deep-water floating production units. The system requirements were carefully compiled aiming to enable an effective collaboration among the participants, creating a suitable environment for discussing, validating, interpreting and documenting the results of the simulations executed during the different phases of an engineering project. To further improve the interpretation capacity and a better comprehension of results the support for immersive 3D visualization is also available in the visualization tool, especially tailored for the Offshore Engineering domain. In order to meet these goals, we devise a Service- Oriented Architecture (SOA) for CEE. This architecture is composed of the integration of different technologies of Computer Supported Collaborative Work (CSCW), Virtual Reality (VR) and Grid Computing (GC). We use a Scientific Workflow Management System (ScWfMS), based on BPEL (Business Process Execution Language), a Grid-enabled software infrastructure for executing engineering simulations, and a Video Conferencing system (VCS) to furnish audio and video collaboration. For visualizing the results, a VR visualization tool, specialized for Offshore Engineering, ENVIRON, has also been developed in conjunction with the PUC-Rio/TecGraf team.

Rehabilitation coatings of offshore equipment rarely perform as well as the original coating, despite the high cost involved. The performance gap is probably due to high relative humidity, salt contamination and limitations on the use of abrasive blast cleaning. Thus, this research aims to deepen the understanding of surface preparation parameters that affect organic coating performance. Carbon steel samples were subjected to a variety of surface alterations consisting of salt contamination, mechanical (wire brushing) and chemical (rust converter and remover) surface preparations followed by coating application and performance testing. The samples were first pre-corroded in a corrosion chamber to mimic degradation from service then surface preparations were performed after which a coating was applied. Coated new samples (RN) and fully corroded samples (SN) were the reference sets, while other samples were prepared to a variety of surface conditions. Visual inspection and electrochemical impedance spectroscopy (EIS) were performed prior to exposure and periodically during accelerated cycling corrosion testing for a period of 30 days. The visual condition of the samples was used to rank the performance of the prepared samples. These results were used as benchmark to decide the optimum EIS method, either phase angle at high frequency or total impedance at low frequency, for early evaluation of the organic coating performance under the conditions studied. Furthermore, adhesion pull-off testing was performed to rank the effectiveness of the coating over various prepared coating. The reference new samples (RN) proved to be the best surface condition and the corroded samples without preparation (SN) had the worst performance for all tests performed. In addition, it was established that salt contamination had a stronger impact on the coating performance than the amount of corrosion product remaining on the surface. Moreover, it was determined that the best preparation approach after precorrosion of the plates was to apply rust converter to the surface before coating. Adhesion measurement was of secondary concern on the studied coated surfaces as cohesive failure occurred on the pre-treatment layers rather than coating adhesion failure between the coating and the treated surface.

The development of offshore wind farms and marine renewable energy devices in the Mediterranean is central to both national, and international, energy strategies for countries bordering the Mediterranean Sea. The ecological impacts of marine renewable energy development in the Mediterranean region, although essential for policy makers, are as yet unknown. The Northern Adriatic is identified as a plausible site for offshore wind farm development. Using the wider region (Adriatic and Northern Ionian) as a case study, this thesis examines the likely impact to the marine environment if an offshore wind farm is established. Site suitability, based on wind speed, bathymetry, and larvae connectivity levels are investigated along with the plausibility of the turbines operating as artificial reefs in the area. As offshore wind farms may alter the larval connectivity and supply dynamics of benthic populations, a connectivity map was constructed to identify areas of high and low connectivity in the Adriatic Sea. The Puglia coast of Italy is a likely larval sink, and displays some of the highest connectivity within the region, suggesting potential inputs of genetic materials from surrounding populations. Considering offshore wind farms could operate as artificial reefs, an in-situ pilot project was established to simulate the presence of wind turbines. Macroinvertebrates colonized the new substrata within the first few months but were lower in abundance when compared to a natural hard substrata environment. Time, turbine location, and the material used for turbine construction all affected the macro-invertebrate communities. In addition, fish abundances, and diversity were lower around the simulated OWF foundations in comparison to a natural hard substrata environment, and no increases in fish abundance occurred around the simulated turbines when compared to reference sites of soft substrata. This observation was validated with the use of an ecosystem modelling software (Ecopath with Ecosim), which simulated the overall ecosystem level impacts that would occur if 50 offshore monopile wind turbines were introduced to the Northern Ionian and colonized by macroinvertebrate communities. When compared to the baseline scenario (no simulated introduction of an OWF), the introduction of new habitat had no discernible impacts to the structure or functioning of the marine ecosystem. Noticeable changes to the ecosystem were only apparent if fishing restrictions were enforced in parallel with the simulated offshore wind farm; the ecosystem appears to become more structured by top down predation. In addition seabirds are also impacted by the reduction of fishing discards as a food source. These results are the first attempt to quantify the suspected benefits of offshore wind farms operating as de-facto marine protected areas.

3D seismic data from the offshore Congo Basin, Angola has been performed in order to do geological interpretation of deep-marine deposits and understand the depositional system in the basin. Architectural elements, such as submarine channels, were mapped to see the geomorphologic characteristic. The interpretation was done by dividing the seismic section into three stratigraphic units that are bounded by horizons interpreted. In order to help the interpretation, surface maps, isopach and attribute maps were extracted and the time slices was also displayed to show the channels migration. Analyses of the channelized depositional environments reveal two distinct depositional styles and results morphologies. Channels interpreted within Unit I and II are defined laterally migrating. The channels of Unit III exhibit a pronounced vertical aggradational motif.Keyword: Submarine channel, lateral channel migration, vertical aggradational channel

Transportation and installation of offshore wind turbines (Tower, Nacelle and Rotor) is a complete process conducted over several phases, usually in sequence. There are several factors that can turn this process into a challenge. These factors can either be due to offshore site conditions or the technical limitations of the installation vessels. Each project has its own characteristic parameters and requires a unique optimum solution. This paper identifies the dynamics of the installation process and analyzes the effects of each phase on the progression of events.The challenges in wind turbine installations due to offshore environment were investigated, the effects of each were explained and their significances were stressed. Special installation vessels were examined and their technical specifications were analyzed in terms of working conditions, dimensions, service performances, and crane capacities as well as projecting future design trends. Several offshore wind farm projects were analyzed; their installation methods were specified, and compared to each other to determine advantages and disadvantages of different pre-assembly concepts. The durations of the sub-phases of the process were defined in terms of different variables such as site conditions and individual vessel performance. These definitions were used for making time estimations, and conducting further analyses regarding the effects of different site specific parameters on the overall project duration.In conclusion, this study considered the main operation parameters in an offshore wind turbine installation context: the benefits and drawbacks of different pre-assembly methods were researched and evaluated resulting in new knowledge and a productive contribution for optimizing “the offshore turbine transportation and installation process”, based on actual time usage.

Amid growing concern over access to sufficient and cheap energy resources, on March 31, 2010 the Obama Administration announced the opening of new exploratory and drilling sites for oil within the United States Outer Continental Shelf. The announcement concerning the Outer Continental Shelf Oil and Gas Strategy came only three weeks before the BP oil spill in the Gulf of Mexico that marked an unprecedented economic and environmental disaster. Though the concern over offshore drilling, especially regarding regulation and environmental impact, has increased in the wake of the oil disaster, the general debate regarding offshore oil drilling has been a concern of environmental activists and domestic energy policy for decades. This thesis examines the development of environmental activism and energy security discourses concerning offshore oil policy in the state of Florida. It places offshore oil drilling at the intersection of discourses of energy security and environmental security by looking at the construction of ocean space as both an informant and product of the discursive constructions of energy security and environmental security. The study aims to provide a deeper understanding of how ocean spaces are incorporated into the economic, national, environmental and social imaginations of Americans, particularly Floridians, and how these imaginations, in turn, dictate offshore oil drilling policy.

Stainless and other high quality steels are used extensively in the topside construction of oil rigs. Steel is heavy, expensive and even the special grades are prone to corrosion in the aggressive marine environment. New materials are needed which are lighter, more cost effective and free from corrosion related problems. Glass fibre reinforced plastics (GRP) have the required properties but their performance in fire conditions is not known. Fire is a very real and possibly catastrophic threat. Before specifying the use of GRP components it is essential to quantify their reaction to fire. Panels and pipes to be used in fire risk areas were the components of interest, and the objectives of the research, based on experimental testing, were as follows: 1) To evaluate GRP laminates for use as structural panel skins, noting their structural and fire performance. 2)To develop incombustible, low cost cores for sandwich panels. 3) To produce sandwich panel design proposals which satisfy specified fire exposure requirements. 4)To assess the fire performance of empty and dry, stagnant water filled and flowing water filled polymer composite pipes with or without fire protection. 5) To use finite difference modelling as part of the design process for fire exposed pipes and panels. Factors of water content for hygroscopic cores and the ablation mechanism of fire exposed GRP were taken account of. 6) To assess the validity of the standard furnace fire resistance test with respect to combustible materials, and with respect to the reproducibility of results between different furnace arrangements.

Le principali attività legate al settore Oil&Gas sono esposte, per la loro natura, a rischi operativi con conseguenze dannose per la saluta umana e per l’ambiente circostante. Malfunzionamenti, errori umani, rilasci o eventi atmosferici possano innescare esplosioni, incendi ed emissioni nocive dalle proporzioni anche catastrofiche. La severità delle conseguenze degli eventi incidentali può essere ulteriormente amplificata dalla propagazione dello scenario primario, dall’unità di riferimento alle unità vicine, dando vita ad eventi che prendono il nome di Scenari Domino. Le vigenti normative introducono l’utilizzo di sistemi di protezione e di barriere di sicurezza, con lo scopo di ridurre l’entità dei danni causati dagli incidenti primari e la possibilità che l’evento si propaghi. Tali eventi sono influenzati dalla geografia e dalle condizioni climatiche degli ambiti territoriali nei quali sono condotte le operazioni. In particolar modo, condizioni climatiche avverse possono influenzare le performance delle barriere di sicurezza, espresse in termini di “Availability” ed “Effectiveness”. L’obiettivo principale del presente lavoro, è quindi quello di ottenere una valutazione quantitativa della riduzione delle performance dei sistemi di sicurezza per installazioni che operano in condizioni climatiche difficili, come le regioni dell’Artico. La metodologia proposta è stata testata su una reale installazione offshore posta nel Mare di Barents.

The constantly increasing complexity of marine and offshore machinery is a consequence of a constant improvement in ship powering, automation, specialisation in cargo transport, new ship types, as well as an effort to make the sea transport more economic. Therefore, the criteria of reliability, availability and maintainability have become very important factors in the process of marine machinery design, operation and maintenance. An important finding from the literature exposed that failure to marine machinery can cause both direct and indirect economic damage with a long-term financial consequence. Notably, many cases of machinery failures reported in databases were as a result of near misses and incidents which are potential accident indicators. Moreover, experience has shown that modelling of past accident events and scenarios can provide insights into how a machinery failure can be subsisted even if it is not avoidable, also a basis for risk analysis of the machinery in order to reveal its vulnerabilities. This research investigates the following modelling approach in order to improve the efficiency of marine and offshore machinery operating under highly uncertain environment. Firstly, this study makes full use of evidential reasoning’s advantage to propose a novel fuzzy evidential reasoning sensitivity analysis method (FER-SAM) to facilitate the assessment of operational uncertainties (trend analysis, family analysis, environmental analysis, design analysis, and human reliability analysis) in ship cranes. Secondly, a fuzzy rule based sensitivity analysis methodology is proposed as a maintenance prediction model for oil-wetted gearbox and bearing with emphasis on ship cranes by formulating a fuzzy logic box (diagnostic table), which provides the ship crane operators with a means to predict possible impending failure without having to dismantle the crane. Thirdly, experience has shown that it is not financially possible to employ all the suggested maintenance strategies in the literature. Thus, this study proposed a fuzzy TOPSIS approach that can help the maintenance engineers to select appropriate strategies aimed at enhancing the performance of the marine and offshore machinery. Finally, the developed models are integrated in order to facilitate a generic planned maintenance framework for robust improvement and management, especially in situations where conventional planned maintenance techniques cannot be implemented with confidence due to data deficiency.

The work presented here is a research thesis of the Ph. D programme in The School of Computing, Science & Engineering at The University of Salford UK. The work presents the evaluation of using explicit finite element techniques for structural non-linear dynamic analysis of a floating offshore wind turbine used for harnessing wind kinetic energy and converting it to electricity. The LS-DYNA3D explicit finite element analysis programme is used in performing the evaluation of the analysis and in creating a full scale model typical to the one evaluated. The developed model (case study) is a 1.4MW power rated floating 3 blades turbine elevated at 46.5 m above main sea level a top a tripod lattice steel tower firmly resting on a moored floating concrete hull buoy, positioned on a concrete circular disk. The mooring cables supporting the floating units in the multi unit farm are designed to share seabed anchoring piles for economic reasons. The model is intended for use in moderately deep waters of up to 500m. The State-of-the-art report is presented concerning wind energy technology, floating offshore wind structures and important features of the LS-DYNA3D code. The theoretical basics for service loads experienced by the floating wind turbine are explored and the loads are quantified. The Verification and validation work on developed small models is presented to ensure confidence in the developed full scale model and the evaluation of the finite element techniques which may be applied to such structures. Development of full scale model, material properties, loads and boundary conditions are presented. Recommendations both for this model and future development are accordingly made.

As machine topologies and technologies mature, the fundamental function of the device is honed. Direct drive machines have the potential to launch the renewable energy sector into a new era of large scale, reliable, offshore power generation. With advancements in new technologies, such as superconductivity, the reduction of generator mass due to incorporation of machine and device structures, the continued advancements in component and system reliability; direct drive generators have the ability to outsize geared wind systems and simplify submerged linear and rotary power generation. The research held within this thesis will focus on improving direct drive power take off systems for offshore renewable energy power generation by splitting the area into four parts. The first part will discuss the various methods of energy extraction within the offshore and marine environment. The future of the sector will be discussed, and a forecast of technological advancement and existing reliability issues will be provided based on current data. The second part will focus on drive trains and direct drive generators, assessing the current topologies and suggesting alternatives that may thrive in a variety of large and small offshore renewable machines. The third part investigates the application of novel linear bearings in direct drive systems for offshore and submerged operation. A brief study of the loads found in wave applications will be presented and the testing of several polymer bearing materials will be outlined. The final part will discuss the potential benefits of flooding the airgap of a direct drive generator with sea water for marine applications. Results will be presented from two linear test rigs and the marinisation of devices will conclude the report.

The use of offshore wind turbines as a source of renewable energy is promising. However, many challenges have to be solved before they will be cost effective. The operation time, without any maintenance required, is desired to be as long as possible, because downtime and maintenance costs are high. Thus it is important that the rotating parts in the turbine have a long operational time. The harsh marine environment, combined with the desire for elongated operating times and little or no maintenance, give rise to many tribological challenges. It is important that the chosen materials and lubricants can withstand the marine environment, and the high loads. The effect of marine environment on lubricating properties of lubricants is not well understood. The objective of this thesis has been to investigate this effect. Two lubricants that are commonly used as gear lubricants in onshore wind turbines were tested in this work; polyalphaolefin and polyalkylene glycol. They were both contaminated with different amounts of artificial seawater in order to investigate the effect on the lubricating properties. The lubricants were tested in a rotating ball-on-disc tribometer, with self-mated stainless steel, and self-mated silicon carbide. Stainless steel was selected as it is commonly used in gear bearings, whereas silicon carbide was chosen due to its promising excellent properties. The results obtained from this work show that PAO has a very low saturation limit for water, and an emulsion will be formed even at low contamination levels. This made the lubricant unstable, and the measured COF were unstable. It was found that the amount of two-body abrasive wear increased as a function of seawater content. The PAG lubricant managed to dissolve much larger quantities of seawater that PAO. But even though the system was one-phased, the results for COF were unstable. Wear induced pitting was found for both clean and contaminated lubricant. It is believed that it is caused by the additive package of the lubricant. For dry tribological testing COF was found to be mush less for self-mated silicon carbide than for self-mated stainless steel. This is as expected, since silicon carbide has shown outstanding tribological properties in previous work.For self-mated silicon carbide testing only abrasive wear could be found for both dry contact, and lubricated. The results from PAO contaminated with seawater, showed a clear increase in COF as a function of seawater content. Further, the COF all stabilized after the running-in period. PAG showed no such trend with increasing amounts of seawater, but the standard deviation of the measurements increased.

>Magister Scientiae - MSc
This study is located within the Bredasdorp Basin which is on the southern continental margin, offshore South Africa. The basin is located between Infanta and Agulhas arches and is a rift basin that is southeastern trending. Sedimentology reports have shown that the basin is predominantly filled by Aptian to Maastrichtian deposits which overlays pre-existing late Jurassic to Early Cretaceous fluvial and shallow marine syn-rift deposits. Devonian Bokkeveld Group slates and or Ordovician-Silurian Table Mountain Group quartzites are shown to be the composition of basement rocks. The study area incorporates only three wells for this research; well F-AH1, F-AH2 and F-AR1. This paper was completed through analyzing and juxtaposing interpretations of results from gamma ray wireline log analysis with core analysis in which these correlations and figures were displayed using Petrel software and Coral Draw respectively. Core analysis resulted in the identification of, sixteen litho-facies for the entire study, which were recognized according to its grain size, texture, sedimentary structures, colour changes, base and top contacts, bioturbation, noticeable minerals, etc. Facies tend to alternate all the way through each well and between different wells with similar facies being present in different wells, but they are not evident in all the cores. Based on the classification of sand bodies, core analysis provides good indication that the general depositional environment of reservoirs within the studied wells are within a marginal marine depositional environment which are tidally influenced. Log signatures typical of sandstone reservoir bodies were discovered in the field where sand bodies are 20 m thick or less and were recognized in the study area. Depositional environments were characterized based on depositional environment similarities: a funnel-shaped facies representing a crevasse splay; a cylindrical-shaped facies representing slope channel-fills representing the transgressive-regressive shallow marine shelf.

L’explosion de la plateforme de forage Deepwater Horizon qui s’est produite dans le Golfe du Mexique en 2010, à l’origine d’une catastrophe écologique sans précédent dans l’histoire des Etats-Unis, nous a conduit à nous interroger sur l’encadrement international de l’activité d’exploration et d’exploitation des hydrocarbures en mer et la protection de l’environnement. Parce que cette activité qui est exercée sur le plateau continental des états, génère des pollutions opérationnelles et accidentelles, et parce que la pollution marine ne connait pas les frontières, l’encadrement international d’une telle activité est de rigueur. L’activité qui a débuté à la fin du XIXe siècle a connu un véritable essor vers les années 70. A ce moment là, les états prennent conscience de la nécessité de protéger l’environnement. Dans le même temps, un régime international encadrant l’activité se développe entre les années 70 et les années 90. Se distingue alors le régime de prévention du régime de réaction. Dans un premier temps l’activité doit répondre à des exigences de prévention. Il n’existe toutefois pas un instrument universel exclusivement dédié à cette activité, de telle sorte que l’on observe un éclatement du régime au travers d’instruments directement applicables à vocation universelle et régionale, complétés par des instruments indirectement applicables relatifs à la protection de l’environnement. Malgré cet éclatement il en ressort que les principaux aspects constituant le cycle de vie de l’activité, partant de la délivrance de permis d’exploration et d’exploitation au démantèlement des plateformes en passant par le contrôle de l’activité sont relativement bien encadrés. Mais malgré cet encadrement nous ne sommes pas à l’abri de la survenance d’une pollution contre laquelle il faudra lutter.Dans ce second temps les états ont donc développé un régime de réaction en réponse aux pollutions opérationnelles et accidentelles. Concernant les pollutions opérationnelles, l’on voit en marge des régimes de prévention déjà existants et imposant certains seuils, se dessiner une lutte empirique contre ces pollutions, essentiellement à l’échelle régionale. Les états prennent conscience que les seuils de pollutions opérationnelles doivent être indéniablement plus contraignants. Concernant la lutte contre les pollutions accidentelles, les états disposent d’un régime international relativement satisfaisant puisqu’une série d’instruments prévoit les mesures imposées aux états que ces derniers doivent prendre en cas de survenance d’une pollution mais surtout parce qu’un instrument universel est dédié à cette problématique. L’existence d’un tel régime ne signifie par pour autant que les états doivent s’en contenter et doivent de cette manière en permanence faire évoluer le droit en vue d’un meilleur encadrement, telle qu’a su le faire l’Union européenne en adoptant en 2013 sa directive sur les accidents majeurs
The deepwater Horizon oil rig explosion in 2010 in the Gulf of Mexico was the most important ecological catastrophe of the United States of America. This event inspired us to study the current international law about the hydrocarbon exploration and exploitation at sea and the protection of the environment. Because this activity takes place on the continental shelf it leads to operational and accidental pollutions, because marine pollution does not have frontiers, therefore legal international control of this activity is necessary.The activity which begun at the end of the nineteenth century, knew a real development around the 70's. At that moment, States became aware of the necessity to protect the environment. At the same time, an international settlement supervising the activity is emerging from the 70's to the 90's. Thus we can distinguish the prevention settlement from the react settlement. First of all the activity must respond to the prevention requirements. Notwithstanding, there is no universal treaty exclusively dedicated to this activity. That is why we do observe a splited settlement through universal and regional treaties directly applicable, completed by treaties indirectly applicable relating to environmental protection. Despite this splitting, we observe that principal aspects constituting the life cycle of the activity, from exploration and exploitation delivery permitted to decommissioning of paltforms, are well controled.Despite this control, a pollution can occur against which one we have to fight.That is why in the second time States developped a react settlement in response to the operational and accidental pollutions. About operational pollutions, we observe around the current preventional settelement which sets limits, developing some new limits through an empirical struggle, essentially at the regional level. States become aware that the limits imposed for operational pollution have to be more restrictive.With reference to the accidental pollutions, a current international settlement is quite satisfactory since various treaties and particularly an universal treaty, decree measures to States, which they fullfil if pollutions occure. This kind of instrument do not significate that States do not have to make the law progress. Indeed the law needs to evoluate permanentaly that is why UE adopted a directive about major accidents.At the same time react settlement not only means fighting pollution but also identifying the liable of the pollution and repare the damage, specifically the per se ecological damage

>Magister Scientiae - MSc
This study was aimed at determining the sedimentary environment, its evolution and facies areal distribution of the Upper Shallow Marine (USM, Late Valanginian). The study was conducted in wells E-S1, F-AH4 and E-W1 in the Bredasdorp basin between E-M and F-AH fields, located in a basinwards transect roughly transverse to the palaeocoast. The wells were studied by logging all the cores in detail between the chosen intervals, followed by facies analysis. Each core log was tied with its respective gamma ray and resistivity well logs. The logs were then correlated based on their log signatures, trends and facies interpretation. The Gamma ray logs show a fining-upwards and coarsening-upwards trend (“hour-glass shape”) in E-S1 and F-AH4 while in E-W1 it shows more accommodation space. These trends are believed to have been influenced by relative sea level changes, such as transgression and regression. Facies analysis identified seven facies in the study area: Facies A, B, C, D, E, F and G. Facies A, B and C were interpreted as fair-weather and storm deposits of the offshore-transition zone, shoreface and foreshore respectively. Facies D was considered as lagoonal mud deposits, while Facies E and F were interpreted as tidal channel and tidal bar deposits respectively. Finally Facies G was considered as fluvial channel deposits. The facies inferred that the sedimentary environment of the study area is a wave-dominated estuary or an Island-bar lagoon system. This led to the production of a conceptual model showing the possible locations for the three wells in the Island bar-lagoon system. The conceptual model inferred the previous findings from PGS (1999) report, that the Upper Shallow Marine beds were deposited in a tidal/estuarine to shoreface setting. This model also supports the findings of Magobiyane (2014), which proposed a wave-dominated estuary for the Upper Shallow Marine reservoir between E-M and F-AH fields, located west of the study area.

>Magister Scientiae - MSc
Southern offshore basins of South Africa are well known as potential provinces of hydrocarbon exploration and production. The complex nature of the Bredasdorp sub-basin’s syn-rift architecture (transform fault system) can have adverse effects on reservoir distribution due to periodic local and regional uplift of horsts and grabens. This present investigation focusses on an integrated approach of the 1AT1-V horizon or early Cretaceous sediments in the Bredasdorp sub-basin to identify the depositional environment and provenance of these sediments as well as their role in regionally complex compositional heterogeneities associated with the late stage rifting of Gondwana break-up. An integrated seismic, sedimentological (including petrography and geochemistry) and ichnologic analysis of the 1AT1-V horizon sediments showed an overall lower regressive element complex assemblage set and an upper transgressive element complex assemblage set that occurred as a >120m thick succession. The analysis identified a mixed-energy deltaic succession followed by an estuarine succession. The 1AT1-V interval (late syn-rift) consisted of nine sedimentary facies associations (and associated petrofacies) on a dipslope setting with variations occurring along the strike and the downdip depositional slope areas. Two overall sequences were identified as a lower regressive and upper transgressive sequence (Element complex assemblage sets). The regressive sequence consisted of middle to distal delta front lobe fringes, hyperpycnal event beds (sourced from basement highs), offshore migrating tidal bars (and associated inter-bar regions), distal mouth bars, terminal distributary channels (and associated inter-terminal distributary regions). The distal delta plain to proximal delta front consisted of interdistributary bays, distributary channels, crevasse splay sub-deltas, mouth bars, tidal flats and offshore embayments. In the laterally isolated depocenter, these deposits also consisted of basement high slopes with upliftment of the basement highs leading to proximal/central embayment to regressive shoreface/foreshore environments. These sequences consisted generally of low diversity and intensities (impoverished abundances) of trace fossils. The paleoclimate inference from this sequence indicates a humid climate with intermediate degrees of weathering intensities (possibly fluctuating arid-humid conditions). The transgressive sequence consisted of estuarine sedimentation with the occurrence of tidal sand ridges and compound dune fields, embayment facies and tidal bars. These sequences consisted of relatively higher ichnodiversities and intensities than their relative regressive sequences. The paleoclimate inference during these times consisted of more arid to semi-arid settings with low degrees of weathering in the source terrain. Local tectonic upliftment and subsidence, with exposed basement highs, gave rise to differential process regimes (tidal, wave and fluvial) and hence depositional facies in the diachronous updip/downdip areas (spatial) and within-stratigraphic (temporal) variations. There are several modern analogues that are similar to the 1AT1-V horizon sequence and they are the Mahakam, Ganges-Brahmaputra, Po, Burdekin deltaic and Satpara lake environments Compaction and dissolution diagenetic features as well as transportation were responsible for the major compositional heterogeneities concerning the reservoir quality and distribution. Proximal and distal sources were identified with first cycle and polycyclic sediments being deposited in the northern and southern part of the basin during the late stages of rifting in the Bredasdorp sub-basin. The provenance lithology has been identified as recycled sedimentary rocks (and their meta-equivalents) with an ultimate source terrain that was largely felsic in nature (Cape granite suite). The northern part of the studied section is suggested to have received sediments from the main metasedimentary rocks of the Cape fold belt (including the Table Mountain Group and Bokkeveld Group) whereas the southern sections received more sediments from the basement highs (recycled Malmesbury Group (and Pre-Cape sediments) and Cape granite suite), which is further supported by seismic data. Provenance analysis revealed that the Cape Fold belt (most recent collision) was possibly a provenance terrain but overprinting of several collisions are also acknowledged. The tectonic setting was envisaged to be of a rifted margin during the break-up of Gondwana. This compositional heterogeneity due to facies and provenance-related terrains had major consequences to the reservoir quality and distribution from the northern part to the southern part of the studied section

A deficient safety culture has been implicated in a number of organisational accidents from a range of high hazard industries. Despite its implications for safety, many questions about safety culture remain unanswered. In order to contribute to the literature on this topic, this thesis set out to investigate the role of trust in safety culture. The oil and gas industry was chosen as the context for study due to the hazardous nature of its work, the industry’s focus on continuous improvement in safety performance and the interest shown by oil companies in participating in safety research. Leading models of safety culture have stressed the importance of trust in developing and maintaining patterns of safe behaviours at work. This thesis proposed a new model of safety culture based on dual attitudes about trust. This model states that explicit attitudes about trust are part of safety climate and that implicit attitudes about trust comprise some of the basic underlying assumptions that are the deepest level of safety culture. In order to test this model, this thesis developed a method to measure implicit attitudes about trust in an industrial setting. Using this method, two studies of dual attitudes about trust were conducted at different UK gas plants. In both of these studies, different patterns of results were found for measures of explicit and implicit attitudes about trust for workmates, supervisors and the plant leadership, respectively. These findings support the proposed model suggest that explicit and implicit attitudes about trust are separate constructs that may influence different types of safety behaviours.  Positive relationships were found between measures of explicit attitudes about trust and self-report items about safety behaviours like reporting incidents and challenging unsafe acts.  These findings were taken as a step toward validating the proposed model.

Magister Scientiae - MSc (Earth Science)
The Orange Basin is underexplored and has shown proven hydrocarbon reserves with the potential for further discoveries. This study is aimed at describing the depositional facies and palaeoenvironment of the drift section in Block 3A/4Aby doingdesktop studies, using seismic analysis, wireline logs and biostratigraphy data. The proximal side of the study area shows structural highs and stratigraphic features such as onlaps, downlaps and pinchoutsin sequences. These structures were mostly observed on the 13A sequence. The 13A sequence is suggested to have been from the Aptian age, which was deposited in transitional inner shelf to pro-deltaic environments. The biostratigraphy data also suggest that the 15A sequence was deposited during the Cenomanian on an outer shelf environment. The 15A sequence, together with the 14 and 16A sequences have faults towards the west, validating the shelf collapse event that took place during the Late Cretaceous. Towards the east of the block there is thinning of sequences which thicken towards the shelf. This could also be observed in the youngest succession, the 22A sequence.The thicker successions reveal similarlog patterns in some wells and sequences; this could be an indication of simultaneousdeposition. The overall picture of the drift sequences in the wells is that they contain sandstones with interlaminated silt which could serve as possible reservoirs and seals in hydrocarbon entrapments.

In the realm of globalization, international sourcing of services contributes to reshape firm’s value chains as the physical dispersion of these activities increases. This reorganization does not simply lead to the replication of domestic activities in a destination providing resource advantages, but, in most cases, it implies profound modifications of the flows of activities, including the reconsideration of the boundaries of the firm. Global sourcing strategies, also called offshoring, seek to increase firm’s efficiency by combining the exploitation of foreign locational advantages with process redesign. When aggregated, these firm-level strategies translate into considerable international exchanges to a point that flows of intermediate services represent about 73% of the total of international trade in services for 2005 (OECD, 2009). These activities present a high degree of heterogeneity in terms of functions concerned, the related domestic industries, motivations, destinations, organizational structure or scope. This wave of internationalization, because of its relative novelty, growth and rapid diversification, draws the interest from the public, political and academic spheres but the comprehension of the determinants shaping the configuration and organization of these activities still remain largely unknown. Based on four essays, this PhD thesis addresses the impact of host-country characteristics and distance factors on the configuration of international sourcing activities in the dimensions of location, governance model and scope of activities.

The first paper studies the country-specific determinants of the interdependent choices of destination and governance model in the global sourcing of services. I explore the simultaneity of these decisions and I jointly estimate their determinants using implementation-level data. Derived from comparative advantages, host-country uncertainty and the global dispersion of tasks, I present three classes of factors driving global sourcing configurations: resource arbitrages, host-country risk and communication barriers. Empirical results confirm that locations with resource or capabilities advantages specific to services – low labour cost, education and labour supply – attract more offshoring activities. However the pursued resource advantages differ depending on the governance model. Country attractiveness for captive implementations presents a higher positive sensitivity to the education-intensive resources, while outsourcing strategies have a greater cost-cutting orientation coming from labour cost arbitrages. Furthermore, the risks inherent to the host-country, in the form of weak formal institutions and inexperience in the destination, have the dual effect of deterring location attractiveness, while they foster the adoption of the outsourcing model compared to the captive one. Communication barriers coming from geographic distance, cultural and linguistic differences have the simultaneous effect of discouraging global sourcing in those locations while, to overcome these constraints, firms favor higher integration with the use of captive models.

This second paper further explores the mechanisms through which home-host country distances affect the choice of governance mode in service offshoring. Using a Transaction Cost Economics approach, I explore the comparative costs of the hierarchical and contractual models to show that different dimensions of distance (geographic, cultural and institutional), because they generate different types of uncertainties, impact offshore governance choices in different ways. Empirical results confirm that, on the one hand, firms are more likely to respond to internal uncertainties resulting from geographic and cultural distance by leveraging the internal controls and collaboration mechanisms of a captive offshore service center. On the other hand, they tend to respond to external uncertainties resulting from institutional distance by limiting their foreign commitment and leveraging the resources and local experience of third party service providers. Finally, I find that the temporal distance component (time zone difference) of geographical dispersion between onshore and offshore countries plays a dominant role over the spatial distance component.

The third section then concentrates on the impact of the institutional environment (regulative) on international sourcing activities. To exploit country-specific advantages, firms that source activities from abroad are forced to integrate the institutional environment into the choice not only of host-country, but also of governance model for their offshore activities. Considering inefficient institutions as drivers of transaction costs, this conceptual paper explores the impact of the host-country regulative environment in the interdependent decisions of country selection and governance model (captive or outsourcing) in firms’ global sourcing strategies. I consider two classes of assets: transferred assets for knowledge/information flows, and local assets sourced from the host location. I show that each class involves specific institutional risks for offshoring practices. In turn, because of the different institutional exposures of the captive model and the outsourced one, the institutional risks associated with transferred and local assets have different implications for the choice of governance model. Firms react to institutional risks relative to transferred assets by internalizing their activity, but they bypass inefficient institutions for local assets using outsourcing. Based on the interaction of the institutional risks relative to each class of assets, I then obtain sufficient conditions that give the firm-optimal combinations of country selection and governance model.

The last section studies how firm-level and country-level risks affect the scope of the process operated in the foreign unit. To prevent appropriation hazard for proprietary content, firms choose a particular disaggregation of the value chain. We argue that, in response to the lack of control offered by internalization and the lack of protection provided by host-country institutions for protecting proprietary content, firms reduce the scope of their activities. In other words, they exploit existing complementarities between the tasks of their value chain using a higher disaggregation of their process and therefore reducing appropriation value for outsiders. Based on a sample of 750 international sourcing projects, regression results on the scope of offshore activities confirm that firms prefer to source discrete tasks rather than entire processes when they lack the protection of internalization and external institutions. In addition, experience modifies these relationships. On the one hand, inexperienced firms do not rely on this slicing mechanism to prevent the loss of control implied by an outsourcing model. On the other hand, the effect of weak institutional protection is perceived as more stringent for inexperienced firms. When host-country institutions are deficient, these firms, compared to the experienced ones, have a higher propensity to operate discrete tasks rather than entire processes.

Doctorat en Sciences économiques et de gestion
info:eu-repo/semantics/nonPublished

This research study is an examination of the influencing factors on lead time performance in a capital equipment supply environment. The research is being undertaken as a case study of the capital equipment supply environment of the offshore oil exploration and production industry on the UK Continental Shelf. The study methodology is justified as a case supply environment, with multiple sources of data from research instruments including: exploratory and detailed interviews and structured survey methods. The literature review examines time-based approaches to supply chain improvement and the literature related to supply chain integration. Relevant literature related to supply chain systems/structures and relationships/infrastructure are examined as potential influencing factors on lead time performance. A background of the generic case environment is provided, along with relevant literature related to the supply chain in oil exploration and production. The results of a survey of the state of integration of the offshore supply chain are presented and analysed, followed by the results of a structured mail survey within the capital equipment environment. The survey information is used to inform the Case Research phase and define a division of the case environment related to different complexity levels. Individual cases are analysed based on the framework from the literature review and refined from the survey phase. The research questions are addressed at the level of each individual case and propositions derived which are then validated based on cross-case comparisons. Aspects of literature that are supported by the study are discussed along with those areas where there is a contribution to literature. Contribution to supply chain theory is justified related to the derivation of a Types Classification Model as a means of understanding the generic nature of a capital equipment supply chain. Contribution to methodology is justified, based on the use of a supply environment for study and the use of a supply chain trace-back method.

This research study is an examination of the influencing factors on lead time performance in a capital equipment supply environment. The research is being undertaken as a case study of the capital equipment supply environment of the offshore oil exploration and production industry on the UK Continental Shelf. The study methodology is justified as a case supply environment, with multiple sources of data from research instruments including: exploratory and detailed interviews and structured survey methods. The literature review examines time-based approaches to supply chain improvement and the literature related to supply chain integration. Relevant literature related to supply chain systems/structures and relationships/infrastructure are examined as potential influencing factors on lead time performance. A background of the generic case environment is provided, along with relevant literature related to the supply chain in oil exploration and production. The results of a survey of the state of integration of the offshore supply chain are presented and analysed, followed by the results of a structured mail survey within the capital equipment environment. The survey information is used to inform the Case Research phase and define a division of the case environment related to different complexity levels. Individual cases are analysed based on the framework from the literature review and refined from the survey phase. The research questions are addressed at the level of each individual case and propositions derived which are then validated based on cross-case comparisons. Aspects of literature that are supported by the study are discussed along with those areas where there is a contribution to literature. Contribution to supply chain theory is justified related to the derivation of a Types Classification Model as a means of understanding the generic nature of a capital equipment supply chain. Contribution to methodology is justified, based on the use of a supply environment for study and the use of a supply chain trace-back method.

Over the last few decades, production processes have become increasingly fragmented: they are divided into ever smaller parts considered as separate activities, which are then spread over various locations in different countries. In other words, value chains for many products are becoming global. This implies that inputs into the production process are sourced from both local and foreign suppliers. The latter mode of sourcing is commonly referred to as offshoring. Expressed as the share of imported in total intermediates, offshoring has grown relatively fast in the recent past. Moreover, its scope has been extended as it increasingly encompasses not only manufacturing but also service activities. A typical example for the former is the sourcing from abroad of parts and components for car assembly. While offshoring of manufacturing activities has been occurring since long and has been largely facilitated by trade liberalisation, the offshoring of service activities such as the provision of accounting or call centre services is a more recent phenomenon that has been fostered by the increased tradability of such services.

With the increasing scale and scope of offshoring, it becomes crucial to get a grasp of its drivers as well as the gains and threats associated with it. The latter are the focal point of the public and academic discussion around offshoring, in particular the potential threats for workers in developed economies. Typical questions that are being raised are whether offshoring leads to job losses in developed countries and whether it favours certain categories of workers and is to the disadvantage of others. These threats are directly linked to the motivations for engaging into offshoring. In this respect, wage costs play a prominent role. But other factors may also influence offshoring decisions, e.g. regulations, in particular those regarding the environment. Last but not least, offshoring may also entail gains for developed economies through the improvements in the efficiency of production. In this PhD thesis, several causes and consequences of offshoring are examined empirically for Belgium.

The first issue that is investigated is whether offshoring of materials and business services affects industry-level employment. An improved offshoring intensity measure is introduced. It is a volume measure of the share of imported intermediates in output split into materials and business services and according to the country of origin of imports, i.e. high-wage and low-wage countries. Estimations of static and dynamic industry-level labour demand equations augmented by offshoring intensities do not reveal a significant impact of either materials or business services offshoring on total employment for Belgium. This result holds for both the manufacturing sector and the service sector and it proves robust to splitting the manufacturing sector into high-technology and low-technology industries.

These results raise the question whether there are actually productivity gains from offshoring. Therefore, estimates of the impact of materials and business services offshoring on industry-level productivity in Belgium are presented. Two features of the analysis are new compared to the existing literature on this subject: the issue is examined separately for manufacturing and market services industries and the possibility of forward and backward spillovers from offshoring, i.e. that productivity gains from offshoring feed through to upstream and downstream industries, is investigated. Results show that materials offshoring has no effect on productivity, while business services offshoring leads to productivity gains in manufacturing. Furthermore, there is no evidence of either forward or backward spillovers from offshoring.

Despite the absence of an industry-level total employment effect, offshoring may alter the within-industry composition of employment. In this respect, a major concern is the worsening of the labour market position of low-skilled workers. This issue is addressed by providing evidence on the impact of offshoring on the skill structure of manufacturing employment in Belgium between 1995 and 2007. Offshoring is found to significantly lower the employment share of low-skilled workers. Its contribution to the fall in the employment share of low-skilled workers amounts to 35%. This is mainly driven by offshoring to Central and Eastern European countries. Business services offshoring also contributes significantly to the fall in the low-skilled employment share. As a complement to the existing literature, the widely used current price measure of offshoring is compared with a constant price measure that is based on a deflation with separate price indices for domestic output and imports. This reveals that the former underestimate the extent of offshoring and its impact on low-skilled employment. Finally, further results show that the impact of offshoring on low-skilled employment is significantly smaller in industries with a higher ICT capital intensity.

Furthermore, attention is drawn to environmental effects of offshoring by asking whether offshoring contributes to reducing air emissions from manufacturing. Indeed, since the mid-90’s, production-related air emissions in Belgian manufacturing have been reduced substantially. It can be shown that the pace of the reduction has been fastest for domestic intermediates. The issue of whether offshoring has played a role in this reduction by replacing domestic intermediates by imported intermediates is widely debated. Here, a decomposition analysis is developed to measure the contribution of offshoring – the share of imported intermediates in total intermediates – to the fall in air emissions for domestic intermediates. Based on the results from this decomposition analysis, it is possible to calculate that 17% of the fall in greenhouse gas emissions, 6% of the fall in acidifying emissions and 7% of the fall in tropospheric precursor emissions in Belgian manufacturing between 1995 and 2007 can be attributed to offshoring.

Finally, emission intensities are also considered as a potential determinant of offshoring. An econometric approach for testing the pollution haven effect for imported intermediate materials is developed. The approach is new with respect to the existing literature on pollution havens through its specific focus on imports of intermediates. The test is embedded in a cost function framework from which a system of cost share equations for variable input factors is derived. The set of potential determinants of the demand for imported intermediate materials includes emission intensities for three types of air pollutants. Their impact constitutes a test of the pollution haven effect. The system of cost share equations is estimated by a within ISUR using data for the Belgian manufacturing sector. Results show some albeit relatively weak evidence of a pollution haven effect for imported intermediate materials.

Doctorat en Sciences économiques et de gestion
info:eu-repo/semantics/nonPublished

This dissertation consists of two independent studies. The first study belongs to the field of environmental economics and the second is on international trade, with a focus on offshoring. In the first study, we investigate firm investment in advanced abatement technology under a heterogeneous firms framework. In contrast to existing literature, we find that the optimal level of investment in advanced abatement technology is an inverted U-shaped function of firm productivity. More-productive firms have superior environmental performance, in the sense that they have lower emission per unit of output. Comparative statics shows that in response to a tighter environmental regulation, more-productive firms tend to raise their investment in advanced abatement technology while less-productive firms do the opposite. Key theoretical predictions are confirmed by Chinese data. The second study analyzes the decision of a multinational firm from a developed country to slice a production chain to allocate different tasks of the production chain globally. The process involves a wide range of tasks that varies from very routine jobs to very research and development (R&D) intensive work. We find that under certain conditions, a drop in offshoring costs (1) leads to more slicing (an increase in the length of production chain) and more offshoring, (2) stimulates R&D, and (3) raises employment in the developed country.
published_or_final_version
Economics and Finance
Doctoral
Doctor of Philosophy

The market for renewable energy and an international power grid is constantly growing. This project has focused on the installation and protection methods for offshore power cables. Long distance cables over e.g. oceans and smaller distances within offshore wind farms. The focus is on three different materials for the protection task; concrete, cast iron and plastics. These materials have been evaluated in aspect to strength, life-length, reliability and environmental impact. Snapp products of Sweden AB have developed a cable protective pipe of polypropylene for offshore usage. This product and its opportunities are thoroughly investigated.

Dans les zones côtières, l’industrie de l’énergie éolienne migre vers l’environnement marin, où de vastes espaces sont encore disponibles avec des conditions de vent plus fort et mieux contrôlé. L’environnement marin impose de nouveaux défis à une industrie éolienne pourtant bien établie. Il est impératif de prédire et de décrire avec précision la ressource éolienne en mer afin de concevoir des solutions techniques rentables. L’écoulement concerné est caractérisé par une couche limite atmosphérique (CLA), turbulente, où la dynamique de l’océan modifie considérablement l’écoulement atmosphérique par une capacité thermique plus élevée, et par des interactions vent-vagues complexes, importantes dans des situations assez courantes. Cette thèse passe en revue et étend les connaissances actuelles concernant les interactions vent-vagues dans la partie inférieure de la CLA Marine (CLAM), où elles peuvent être importantespour la caractérisation de la ressource éolienne. La CLAM est étudiée par des expériences physiques et numériques, afin de révéler le rôle des mouvements Induits par les Vagues (IV) transférés de la mer vers l’atmosphère. Grâce à l’utilisation d’expériences physiques et numériques complémentaires, de nouvelles perspectives sur les processus d’interaction vent-vague sont obtenues
In coastal areas, the wind energy industry migrates to the offshore environment, where huge spaces are still available in stronger and better behaved wind conditions. The offshore environment imposes new challenges to a well established wind energy industry. It is imperative to accurately predict and describe the offshore wind resource in order to design cost efficient solutions. The concerned flow is characterized by a turbulent Atmospheric Boundary Layer (ABL) where the ocean’s dynamics significantly alter the atmospheric flow through higher heat capacity and complex wind-wave interactions important in fairly common situations.So this Thesis reviews and extends the current knowledge regarding Wind-Wave interactions in the lower part of the Marine ABL (MABL), where they are possibly significant in the characterization of the wind resource. The MABL is investigated through physical and numerical experiments, to reveal the role of Wave Induced (WI) motions transferred from the sea into the atmosphere. Thanks to the use of complementary physical and numerical experiments, new insights on the wind-wave interaction processes are obtained

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 75-76).
Worldwide energy demand is growing rapidly, and there is great interest in reducing the current reliance on fossil fuels for uses such as power generation, transportation, and manufacturing. Renewable energy sources, such as solar and wind, are abundant but have very low power densities. The US is in the process of approving its first offshore wind farm, located in Nantucket Sound. Geotechnical factors will play a large role in the development of offshore wind projects due to the high cost contribution from foundations, and the high loads associated with storm conditions. Offshore wind turbine foundations provide unique design challenges. First, various foundation alternatives exist, so it is important that an appropriate cost-effective foundation type be selected. Second, the loads and soil conditions will vary for each location. Therefore, it is important to ensure the foundation can adequately support vertical and horizontal loads. Finally, each turbine manufacturer has unique deflection and rotation criteria. Therefore, the foundation should perform within those tolerances, even under worst-case loading. This thesis considers the performance of a monopile foundation under typical vertical and horizontal storm loading conditions. Capacity, deflection, and rotation of a proposed monopile foundation are calculated by various methods to simulate the design procedure. The results show that very stiff foundations are required to keep pile head movements within design tolerances.
by Duncan Rath Kopp.
M.Eng.

Addressing the decommissioning issues is vital to ensure a sustainable and effective process of such an essential part of the project life cycle. While there is a set of good practices and regulations that govern most of the decommissioning activities, the cable decommissioning issue is still in a big debate and often left abandoned at the seabed due to environmental concerns, as justified by most developers. This paper is aiming to understand the environmental and economic consequences of cable decommissioning. The available research papers and reports that are dealing with cable decommissioning issues have been reviewed. The cables are often decommissioned using similar methods to installation. However, there are no regulatory obligations to removing the cables in most countries. Cable installation will be associated with environmental impacts, but they are considered to be negligible. Additionally, Recycling cables’ copper is beneficial in both aspects environmentally and economically as copper prices are on the rise. A comparison between the ESs and decommissioning programs in a number of OWFSs have been conducted to understand the justification used for abandoning the cables. Most of the decommissioning reports have considered cable decommissioning to cause “considerable damage to seabed ecology”. However, that contradicts what was found in the ESs, where the impact level was considered negligible and anticipated to be similar to installation. It was unclear whether the abandonment of cables was driven by environmental considerations or not. A case study has been selected to compare cable and monopile decommissioning costs and the contribution of each component to the total decommissioning cost, including possible revenue generated from recycling. It was found that the cost-benefit of cable decommissioning is incomparable to monopile decommissioning as the latter is very costly, and the possible residual value is insignificant when compared to cables. Moreover, it is possible that the total cable decommissioning cost to be largely offset by the revenue generated from copper resell. Additionally, the cable decommissioning total cost can be almost paid by recycling cables if copper prices increase in the near future.

The case of European offshore carbon dioxide sequestration informs us that the international and European environmental liability frameworks for the protection of the marine environment are developed but several issues remain to be addressed and that they are still not completely ready to accommodate this technology. A detailed look is taken at the status of offshore CCS under public international law: the United Nations Convention on the Law of the Sea, the London Convention, the London Protocol, and the OSPAR Convention. Subsequently, European law is analysed, the CCS Directive and the Environmental Liability Directive in particular. Finally, the liability related to carbon dioxide transport by pipelines is examined.

The health care of those who work in remote places associated with hostile environments is reviewed, concentrating on the offshore oil industry and Antarctic populations. An understanding of associated environmental hazards is essential for adequate health care and particular attention is paid to the hyperbaric environment and to environmental heat and cold. The basic medical problems in remote health care are evaluated in three related studies. The first examines 2,162 personnel who required medical evacuations from the offshore structures of four North Sea operating companies, the second with 5,894 presentations from offshore at the A&E department of Aberdeen Royal Infirmary, while the third examines 100 annual medical reports from British Antarctic Survey stations.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 269-281).
Although finite element (FE) methods are well established for modeling geotechnical problems in soil masses and soil-structure interaction, most prior research on large deformation problems has been limited to simplified assumptions on drainage conditions and constitutive behavior. This thesis investigates two large deformation problems in soft clay and proposes a methodology for performing coupled flow and deformation analyses with advanced effective stress models. The first part of the research focuses on realistic 3-D finite element analyses (using AbaqusTM Standard) of a conductor (steel pipe pile) embedded within soft marine clay subjected to large lateral deformations caused by drift/drive-off of a drilling vessel. The proposed analyses use coupled pore pressure-displacement procedures together with the MIT-E3 soil model to represent the anisotropic, non-linear and inelastic effective stress-strain-strength properties of deepwater marine sediments with input parameters derived from a series of laboratory element tests performed on reconstituted Gulf of Mexico (GoM) clay. The numerical predictions are evaluated through comparison with experimental results from centrifuge tests with a well-instrumented model conductor. The FE results accurately predict the measured bending moment distribution along the length of the conductor and the spread of plastic strains within the conductor itself. The study has also shown the effects of soil behavior on local pile-soil interactions, enabling simplified analyses using macro-elements. The FE results have been used to calibrate input parameters for BWGG framework (Gerolymos & Gazetas, 2005), the Bouc-Wen (BW) model extended by Gerolymos and Gazetas (GG), that simulates generalized hysteretic pile-soil interactions and allows for degradation in soil resistance associated with geometric non-linearities. The second application considers the effects of partial drainage for large deformation, quasi-static piezocone penetration in clay. The proposed axisymmetric FE analysis procedure introduces automated remeshing and solution mapping technique (similar to RITSS; Hu & Randolph, 1998) within a commercial FE solver. We have analyzed the penetration resistance for a piezocone device using two elasto-plastic soil models (MCC, MIT-E3) and the recent elasto-viscoplastic MIT-SR soil model (Yuan, 2016) over a range of steady penetration velocities. The MCC predictions are in very good agreement with laboratory measurements of tip resistance and penetration pore pressures measured in centrifuge model tests in reconstituted kaolin. The results from more advanced soil models illustrate the impacts of anisotropic, rate dependent soil behavior on penetration tests in natural clays and are within the range of empirical measurements. The proposed analyses provide a complete framework that can now be used to investigate effects of partial drainage that occurs in piezocone tests for soils (such as silts) of intermediate permeability.
by Zhandos Y. Orazalin.
Ph. D.

Offshore wind has proved to be one of the most reliable and clean energy sources over the last few years. The industry has experienced a significant growth, with an increase of 101% only in 2017 compared to 2016. This raises the importance of the need for more secure power supply systems, which can be used for controlling the offshore farms during disconnections from the main grid. Nowadays, diesel generators are being used to feed auxiliary services of the offshore wind turbines in situations of emergency. However, as the marine renewable energy industry evolves, tidal energy parks have the potential to replace diesel generators and provide a more sustainable and eco-friendly solution for a long-term auxiliary power system. Moreover, they have the potential to produce extra power, which can be either stored for future use or linked directly to distribution. This report demonstrates a technical, financial and environmental assessment of a potential tidal park within an offshore wind park. Comparison with alternative sources for emergency power supply is also performed. Three alternative locations with high wind speeds and large tidal resource around the UK coast and four different groups of tidal devices are evaluated and compared for the implementation of this solution with the use of ArcGIS maps and other accessible marine data. The Aberdeen wind farm and the tidal kites are selected for further investigation and cost analysis. Seven tidal kites with average power 700 kW and rated power 3.5 MW can provide adequate power to the offshore wind farm for three months without grid connection, whereas they can also provide excess of energy on daily basis when grid disconnection does not occur. The total cost for the project would be approximately 301.6 MSEK. Due to the current renewable energy market, the project is not feasible without high investment risks. However, this study should be evaluated again in the near future when the cost of the tidal device will be further decreased.
Havsbaserad vind har visat sig vara en av de mest tillförlitliga och rena energikällorna under senare år. Inom denna industri har en betydande tillväxt skett, med en ökning med 101% år 2017 jämfört med 2016. Detta relaterar till behovet av säkra elförsörjningssystem, som kan användas för att styra havsbaserade vindraftverksparker under urkoppling från huvudnätet. Numera används dieselgeneratorer som reservkälla till havsvindkraftverk i nödsituationer. Men när den marina förnybara energiindustrin utvecklas, har tidvattenkraftverk potential att ersätta dieselgeneratorer och ge ett mer hållbar och miljövänlig långtidslösning. Dessutom har de potential att producera extra el, som antingen kan lagras för framtida användning eller kopplas direkt till distributionsnätet. Denna rapport erbjuder en teknisk, finansiell och miljömässig bedömning av en potentiell tidvattenkraftverkspark kopplad till en havsvindpark. Jämförelse med alternativa källor för strömförsörjning genomförs också. Tre alternativa platser med hög vindstyrka och stora tidvattenresurser längs Storbritanniens kust och fyra olika grupper av tidvattenanordningar utvärderas och jämförs med hjälp av kartor och andra tillgängliga marina data. Aberdeen vindkraftpark och tidvattendrakar väljs för ytterligare undersökning och kostnadsanalys. Sju tidvattendrakar med genomsnittlig effekt på 700 kW och nominell effekt 3,5 MW kan ge tillräckligt med el till havsvindkraftverk i tre månader utan nätförbindelse, medan de också kan ge överflöd av energi dagligen när strömavbrott inte förekommer. Den totala kostnaden för projektet skulle vara cirka 301,6 MSEK. På grund av läget idag på elmarknaden för förnybar energi, är projektet inte genomförbart utan höga investeringsrisker. Men den här studien bör utvärderas igen inom en snar framtid när kostnaden för tidvattenanordningen har minskat.

Offshore oil platforms are used for the exploitation and production of hydrocarbons and consist of a processing plant and a utility plant. The oil and gas industry operations are energy-intensive and, in the case of offshore platforms, the need to decrease energy consumption and reduce CO2 emissions has increased. In the oil and gas industry, the ISO 50001 standard promotes the implementation of energy management systems and proposes indicators based on energy. Interestingly, after several decades of knowledge of the concept of exergy, this has not been formally implemented in the programs and strategies of the oil and gas industry organizations. In this research, the implementation of the exergy method and the carbon capture and storage strategy for the assessment of the performance of a floating, production and storage offloading units FPSO is proposed. FPSO platforms and their processing and utility plants may have different configurations depending on, among others, the reservoir characteristics and production requirements. The possible configurations can therefore be numerous. In this sense, some operation scenarios based on different well-fluid compositions and operation modes are studied. The platform models are developed and simulated using the software Aspen HYSYS®. Results show that, on average, the reduction of 88.8% in CO2 emissions is penalized with a reduction in exergy efficiency of 1.7 points. Further, results allow a better understanding of exergy and environmental performance of the FPSO.
Plataformas de petróleo offshore são utilizadas para a exploração e produção de hidrocarbonetos e consistem em uma planta de processamento e uma planta de utilidade. As operações da indústria de petróleo e gás são de energia intensiva e, no caso de plataformas offshore, é necessário cada vez mais diminuir o consumo de energia e reduzir as emissões de CO2. Na indústria de petróleo e gás, a norma ISO 50001 promove a implementação de sistemas de gestão de energia e propõe indicadores baseados em energia. Entretanto, após várias décadas de conhecimento do conceito de exergia, este não foi formalmente implementado nos programas e estratégias das organizações da indústria de petróleo e gás. Neste trabalho, propõe-se a implementação da análise exergética e a estratégia de captura e armazenamento de carbono para a avaliação do desempenho de unidades flutuantes, de produção, de armazenamento e transferência FPSO. As plataformas FPSO e suas plantas de processamento e utilidade podem ter diferentes configurações dependendo, entre outras, das características do reservatório e dos requisitos de produção. As configurações possíveis podem, portanto, ser numerosas. Neste sentido, são estudados alguns cenários de operação baseados em diferentes composições dos fluidos do poço e em três modos de operação. Os modelos de plataforma são desenvolvidos e simulados usando o software Aspen HYSYS®. Os resultados mostram que, em média, a redução de 88,8% nas emissões de CO2 é penalizada com uma redução da eficiência exergética de 1,7 pontos. Além disso, os resultados permitem uma melhor compreensão da exergia e desempenho ambiental do FPSO.

Research in sustainable macroalgae aquaculture has been gaining hype (e.g. Seafarm) to provide advancements in new significant sources of food, feed, materials and bio-energy. Despite the fact that in Asia the offshore production of macroalgae is established for many decades, in Europe is still in its infancy. The issue on where to find suitable cultivation areas without conflicting with current uses to respect the environment and the socio-economic activities is a great challenge. This Master of Science thesis aimed to find suitable offshore areas in order to facilitate implementations of macroalgae cultivations in the Swedish West Coast. Thirteen criteria in environmental, economic and social sustainability aspects were identified and employed (e.g. Depth, Distance to Ports, and Natural and Preserved areas (NPAs)), and the tools Geographic Information Systems (GIS) and Multi-criteria Analysis (MCA) were used in the form of GIS-MCDA, an integrated method available in Idrisi. To aggregate the criteria, Boolean and Weighted Linear Combination (WLC) techniques were applied. The results showed that Boolean areas cover 537 km2 (6,98% of the study area). The best suitable areas, possessing the maximum suitability index 10, that resulted from two WLC models comprise 5 km2 (0,07% of the study area) and 26 km2 (0,34% of the study area) including and excluding the criterion NPAs as constraint, respectively. The results further indicated that GIS-MCDA models excelled in providing an overview for effective spatial decision-making. Both techniques play a role in suitability analysis and complement each other in finding an optimal site which could be carefully selected out of the identified areas. It is recommended that areas with a suitability index 10 be chosen inside Boolean suitable areas. Moreover, this study could act as a driving force to build a resilient planning framework that would boost sustainable placement and development of offshore macroalgae cultivations.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.
Includes bibliographical references (leaves 54-61).
Pile driving has been of interest to geotechnical engineers for a very long time. Originally, empirical pile driving formulae were used to interpret pile displacements caused by a hammer blow. Smith (1960) proposed a numerical solution for wave propagation in an elastic pile using a finite difference scheme, with lumped mass representation and simple rheological laws for pile-soil interaction. Since then, many significant parameters affecting pile driving have been included in the wave equation analysis. The offshore industry finds much application of pile driving analysis, especially after recent developments in instrumentation and electronic computational tools. Positioning of wind farms offshore and designing a foundation for a floating platform is a challenge to geotechnical engineers. One of the methods to anchor the floating platform is to tether it down to the seabed with help of driven piles. This thesis considers a typical offshore site for designing a driven pile for floating wind farm. The Author has carried out a set of numerical simulations to analyze pile driving at this site using a commercial program (GRLWEAP), and illustrates how this program can be used in pile design.
by Siddharth Chauhan.
M.Eng.