21, [58] leaves : ill. ; 28 cm.

Doctorat en sciences sociales, politiques et économiques / info:eu-repo/semantics/nonPublished

1. Introduction and Context Oil as a source of energy is an undisputed reality of the age in which we live. The oil and petroleum industry is an essential and valuable part of the South African economy. It follows then that transportation in this industry is of crucial importance. Simply put, without the efficient transportation of the various crude and petroleum products, the energy requirements of the country could not be met. While there are various modes of transportation within South Africa servicing this industry, this study will concentrate on the carriage of crude oil and petroleum products by sea, and its handiing in the associated ports. The main objective will be to examine the pricing structure raised by the ports of South Africa against the oil industry for th'a transportation of the crude and petroleum products moving through the various ports. 1.1 Background During this researcher's tenure as a shipping agent on behalf of the oil majors in the ports of South Africa, the pori authorities' charges were dealt with on a regular basis. The inherent problems with the charges and the resulting conflicts created between the port authorities and the oil majors became quite familiar to the researcher during her years of working with the two parties. 1.2 Objectives of the Study This study will start by looking at the economic theory and principles of port pricing structures. Chapter Two will work toward outlining the optimal port pricing structure a port authority should adopt, in order to ensure it is working according to sound economic principles as well as meeting the various objectives of the stakeholders utilising the port's infrastructure, superstructure and services. Chapter will focus on the South African oil industry and the importance of crude oil and its petroleum derivates as an energy source. The industry will placed in larger context of SADC, the various role players will be identified and the modes of transport used for the carriage of crude and petroleum products will outlined. The chapter will close with a presentation of the product costing for the petrol price South African consumers' pay at the petrol pumps. Chapter Four presents an overview of the ports South Africa, their facilities, their management arrangements and their pricing structures. A brief. history of the ports will be followed by a discussion of the need a restructuring process and an outline the proposed privatisation process will be Following this, the current management structure related pricing tariffs will be detailed. Chapter Africa and will explore the relationship ben.veen of the ports of South oil industry. history of this relationship will be set out, followed by the current dynamics affecting it. The study will then move on to examine the oil industry infrastructure found in these ports in terms of ownership management of Port tariffs and the question of who actually pays what will be addressed. The that created and continue to create tensions between oil majors and the ports of South Africa will highlighted. The chapter will conclude by presenting an ideal pricing structure, which could work towards resolving some of these issues. Chapter Six will discuss two different international models based on energy demand and supply similar to South African situation. The port pricing structure of these models will then be compared to that of South African ports in order to present a best-working practice. The purpose of this is to bring in an international perspective for the ideal pricing structure presented with the conclusion in Chapter Seven. 1 Methodology of the study The researcher initially used interviews with the various bodies as a means of gathering information. These data were then verified against textual information sources. Statistical figures were gathered and correlated into formats, which could then verify -, or disprove -- different hypotheses put forward in the study. / Thesis (MBA)-University of Natal, 2003.

O escoamento bifásico em golfadas está presente em diversos processos industriais, entre eles a produção e transporte do petróleo. Ele se caracteriza pelo escoamento de um pistão de líquido com grande quantidade de movimento seguido por uma bolha de gás compressível. A repetição destas estruturas ocorre de forma intermitente. Nas últimas décadas, surgiram alguns modelos para a simulação deste tipo de escoamento, como os modelos eulerianos de dois fluidos e drift flux, e lagrangeano de seguimento de pistões (slug tracking). Com base no trabalho de Renault (2007), uma metodologia lagrangeana foi desenvolvida para monitorar e acompanhar o processo de iniciação do escoamento em golfadas em tubulações horizontais e levemente inclinadas de modo autônomo. Partindo-se do modelo de dois fluidos com aproximação unidimensional, as equações de conservação de massa e balanço de quantidade de movimento foram simplificadas. O sistema de equações resultante para o domínio de gás foi discretizado utilizando-se o método de diferenças finitas e resolvido através do algoritmo TDMA. O movimento do líquido sob as bolhas foi modelado de modo semelhante às equações de águas rasas (shallow water equations). Um programa computacional na linguagem Intel Visual Fortran foi desenvolvido para simular o processo de iniciação do escoamento em golfadas, a partir do escoamento estratificado líquido-gás. O crescimento das ondas na interface líquido-gás foi monitorado numericamente, assim como os pistões de líquido que se formaram em decorrência do crescimento das ondas. Foram realizadas simulações numéricas, para diferentes condições de vazão de líquido-gás, com a finalidade de avaliar a capacidade do modelo de gerar pistões. Para a validação dos resultados numéricos, foram realizadas medidas experimentais na bancada de escoamento bifásico existente no NUEM/UTFPR. Os dados foram obtidos utilizando-se sensores resistivos. Foi verificada uma forte dependência dos resultados do modelo em relação à malha. Devido a isto, foi proposto um critério para limitar o refinamento máximo da malha. Uma análise linear levou a conclusão que o modelo apresenta maiores taxas de crescimento de onda em relação ao modelo de dois fluidos. Os resultados numéricos mostraram boa concordância com os dados experimentais, porém apresentam melhor desempenho quando próximos à região onde o modelo se encontra mal posto numericamente. / Many industrial processes like crude oil transportation in pipelines operate on two-phase flow regime, especially in slug flow pattern. Slug flows are characterized by the intermittent succession of liquid slugs having a large momentum, followed by long bubbles of compressible gas. This kind of flow has been a topic of research over the last decades; however, few mathematical models for this complex flow can be found in the literature. Among those, one might mention the Eulerian two-fluid and drift flux, and the Lagrangian slug-tracking. Based on the work of Renault (2007), this work presents a Lagrangian methodology to capture the process of slug initiation for horizontal and near horizontal pipes. Starting from one dimensional two-fluid model, the equations of momentum and mass conservation were simplified. The motion generated by the dynamic pressure of the gas was decoupled from the slow movement of the liquid film. The resulting system of equations for the gas phase was discretized using the finite difference method and solved with the tri-diagonal matrix algorithm (TDMA). The liquid motion in the bubbles was then modeled by a modified version of shallow water equations. A software using Intel Visual Fortran language to simulate the process of slug initiation in a gas-liquid stratified flow was developed. Wave growth in the liquid-gas interface was numerically monitored until one of those waves reached the top of the pipe to form a slug. Numerical simulations were performed for different gas-liquid flow conditions, in order to evaluate the ability of the model to generate slugs. Experimental data to validate the code were gathered at the experimental facility of NUEM/UTFPR. The data were acquired using two-wire resistive sensors. The numerical results showed to be strongly dependent on mesh size. Because of this, a limiting criterion for the mesh size was developed. The linear analysis showed higher wave growth rate to this model than the two-fluid model. The results showed consistency when compared to the experimental data, especially in the neighborhoods of the region where the model is ill-posed.

Orientador: Arnaldo Vieira Moura, Cid Carvalho de Souza / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-12T08:44:27Z (GMT). No. of bitstreams: 1 Cire_AndreAugusto_M.pdf: 961770 bytes, checksum: 5fad1ce7143a7b6505cc4194ac56dc65 (MD5) Previous issue date: 2008 / Resumo: Esta dissertação de Mestrado trata de um problema real de escalonamento, no qual uma complexa rede de dutos é utilizada para distribuição de derivados de petróleo e bio-combustíveis de refinarias a mercados locais. Dutos constituem a alternativa de transporte mais vantajosa em termos econômicos e ambientais, mas trazem consigo um amplo conjunto de restrições operacionais difíceis, envolvendo seqüenciamento de produtos, capacidade de tanques, controle de taxa de vazão, controle de estoque e muitas outras. O objetivo do problema está em escalonar operações de bombeamento nos dutos de forma a satisfazer as demandas locais em cada órgão de distribuição, dentro de um horizonte de planejamento pré-definido. Para resolvê-lo, este trabalho propõe uma nova abordagem híbrida composta por duas fases. Primeiramente, uma fase de planejamento define os volumes de produto que devem ser transmitidos entre órgãos para que as demandas sejam completamente atendidas. Em seguida, uma fase de escalonamento é responsável por criar e escalonar as operações de bombeamento, de forma a garantir que os volumes definidos na fase anterior sejam efetivamente enviados. Esta disserta¸c¿ao foca na fase de escalonamento, e duas formulações em Programação por Restrições (PR) são apresentadas para modelá-la. Conforme foi verificado, a flexibilidade de PR 'e fundamental para representar e satisfazer restrição que, usualmente, são desconsideradas na literatura, mas que são essenciais para a viabilidade operacional das soluções. A estratégia completa foi implementada e produziu resultados adequados e promissoras para 5 instâncias reais fornecidas pela Petrobras. Tais instâncias cont¿em 30 dutos, mais de 30 produtos e 14 órgãos de distribuição que contemplam cerca de 200 tanques. / Abstract: This dissertation deals with a very difficult overly-constrained scheduling challenge: how to operate a large pipeline network in order to adequately transport oil derivatives and biofuels from refineries to local markets. Pipeline network systems are considered the major option for transporting these product types, in view of their many economic and environmental advantages. However, they pose serious operational difficulties related to product sequencing, flow rates and tank capacities. The challenge is how to schedule individual pumping operations, given the daily production and demand of each product, at each location in the network, over a given time horizon. In order to tackle this problem, we propose a novel hybrid approach which comprises two phases. Firstly, a planning phase decides the necessary volume transmission among depots to satisfy the given demands. Finally, a scheduling phase generates and schedules the pumping operations that guarantee the required volume transmission. This dissertation focuses on the scheduling phase, in which two new Constraint Programming (CP) models are proposed. The CP flexibility plays a key role in modeling and satisfying operational constraints that are usually overlooked in literature, but that are essential in rder to guarantee viable solutions. The full strategy was implemented and produced adequate and promising results when tested over 5 large real instances from Petrobras. These instances have a complex topology with around 30 interconnecting pipelines, over 30 different products in circulation, and about 14 distribution depots which harbor more than 200 tanks. / Mestrado / Pesquisa Operacional / Mestre em Ciência da Computação

Thesis (MBA)--Stellenbosch University, 2011. / Petroleum fuels energy supply and its availability is an essential precondition for socio-economic development in any economy. Energy is required in meeting the basic human needs such as food, shelter, health, education and for economic activities such as transport, agriculture and mining. Botswana’s energy consumption is dominated by petroleum fuels. The country has no known petroleum reserves and it has to import all its petroleum requirements in refined form, from the neighbouring South Africa. The study focuses on the challenges of security of supply of petroleum products in Botswana. What is at stake is to identify alternative supply sources and routes of petroleum products to Botswana, thus reducing the risk of wholly dependence on South Africa for the supply. A major goal is to develop alternative sources and routes from neighbouring countries. This can be achieved by the Botswana Government taking advantage of regional cooperation with neighbouring countries. The study explores other approaches to reduce the high dependence on South Africa. One of the possible solutions is for Botswana Government to establish a state owned oil company which could play a catalytic role in the implementation of many of the steps considered in this study. This company could, for example, be charged with crude oil exploration in Botswana and with steps to assist locally owned Botswana companies to establish themselves in the marketing and distribution of petroleum. Much will, however, depend on the resources that can be mobilised by the Botswana Government for such a State Oil Company. The study is based on secondary data obtained mainly from the Division of Energy in the Ministry of Minerals, Energy and Water Resources. Feasibility studies conducted by consultants engaged by the Ministry played an important role in the literature underlying this report.

Este trabalho desenvolve uma estrutura de otimização que auxilia a tarefa de escalonamento das atividades de transporte de derivados de petróleo em uma rede de dutos. A malha dutoviária em estudo é utilizada para o transporte de derivados leves de petróleo com alto valor agregrado, sendo composta por 9 áreas (3 refinarias, 1 porto e 5 terminais). dentro deste cenário, a busca por resultados práticos considerando uma carga computacional aceitável torna-se um grande desafio. A abordagem adotada baseia-se na decomposição do problema, onde é investigada a aplicação de um modelo de programação linear inteira mista (Mixed Integer Linear Programming - MILP) com domínio de tempo contínuo para determinar o escalonamento das operações de curto-prazo da rede de dutos. Em função da abordagem hierárquica proposta, a etapa de ordenação da lista de bateladas utilizada na fase de temporização foi inicialmente desenvolvida através de heur´siticas construtivas que falham em situações particulares. Neste sentido, o problema de ordenação é reformulado através do emprego de estruturas de alto nível presentes em técnicas de programação lógica por restrições (Constraint Logic Programming - CLP). Na forma como é apresentada, a estrutura desenvolvida vem sendo extensivamente testada em cenários reais envolvendo mais de 100 bateladas para o horizonte de aproximadamente um mês. A partir desta ferramenta, novas programações de curto-prazo serão propostas, programações existentes serão validadas e informações de diagnóstico da rede serão obtidas de forma a auxiliar o processo de tomada de decisão operacional. / This work addresses an optimisation structure to support the operational decision-making of scheduling activities in a real world pipeline network. The used scenario to transport petroleum derivaties involves 9 areas (3 refineries, 1 harbour, and 5 distribution centres). Thus, the computational burden for determining a short-term scheduling within the considered scenario is a relevant issue. A decomposition approach is proposed to address such real-world problem. A continuous-time mixed integer linear programming model (MILP) is studied and used to determine the operational short-term scheduling. In this context of multilevel hierarchical structure, sequencing of activities are carried out by a heuristic algorithm which can fail for some particular cases. Thus, we propose to reformulate the sequencing problem by using high-level constructs of Constraint Logic Programming (CLP). The optimisation structure has been extensively tested in typical operational scenarios which, involve in general more than 100 batches. The scheduling horizon is considered to be about 1 month. Many insights have been derived from the obtained solutions, and the proposed approach can support the decision-making process.

Este trabalho desenvolve uma estrutura de otimização que auxilia a tarefa de escalonamento das atividades de transporte de derivados de petróleo em uma rede de dutos. A malha dutoviária em estudo é utilizada para o transporte de derivados leves de petróleo com alto valor agregrado, sendo composta por 9 áreas (3 refinarias, 1 porto e 5 terminais). dentro deste cenário, a busca por resultados práticos considerando uma carga computacional aceitável torna-se um grande desafio. A abordagem adotada baseia-se na decomposição do problema, onde é investigada a aplicação de um modelo de programação linear inteira mista (Mixed Integer Linear Programming - MILP) com domínio de tempo contínuo para determinar o escalonamento das operações de curto-prazo da rede de dutos. Em função da abordagem hierárquica proposta, a etapa de ordenação da lista de bateladas utilizada na fase de temporização foi inicialmente desenvolvida através de heur´siticas construtivas que falham em situações particulares. Neste sentido, o problema de ordenação é reformulado através do emprego de estruturas de alto nível presentes em técnicas de programação lógica por restrições (Constraint Logic Programming - CLP). Na forma como é apresentada, a estrutura desenvolvida vem sendo extensivamente testada em cenários reais envolvendo mais de 100 bateladas para o horizonte de aproximadamente um mês. A partir desta ferramenta, novas programações de curto-prazo serão propostas, programações existentes serão validadas e informações de diagnóstico da rede serão obtidas de forma a auxiliar o processo de tomada de decisão operacional. / This work addresses an optimisation structure to support the operational decision-making of scheduling activities in a real world pipeline network. The used scenario to transport petroleum derivaties involves 9 areas (3 refineries, 1 harbour, and 5 distribution centres). Thus, the computational burden for determining a short-term scheduling within the considered scenario is a relevant issue. A decomposition approach is proposed to address such real-world problem. A continuous-time mixed integer linear programming model (MILP) is studied and used to determine the operational short-term scheduling. In this context of multilevel hierarchical structure, sequencing of activities are carried out by a heuristic algorithm which can fail for some particular cases. Thus, we propose to reformulate the sequencing problem by using high-level constructs of Constraint Logic Programming (CLP). The optimisation structure has been extensively tested in typical operational scenarios which, involve in general more than 100 batches. The scheduling horizon is considered to be about 1 month. Many insights have been derived from the obtained solutions, and the proposed approach can support the decision-making process.

The playing field upon which actors, both state and non-state, develop strategies to secure existing supplies of oil and seek access to new ones is as systemically, politically and strategically complex is as it is geographically vast. In considering this activity, the terminology used by pundits and journalists to describe the significance of issues such as oil demand, the complexities of access to petroleum and concerns over security threats to supplies of oil is familiar. Juxtapositions such as the ‘geopolitics of oil', ‘energy geopolitics', the ‘geopolitics of resource wars' and the ‘geopolitics of oil and gas' are all familiar. But what do they mean when they use ‘geopolitics' in this context? Thus, by extension, can petroleum geopolitics - a hybrid conceptual construction used in this thesis - be disassembled into its component parts, analysed and systematically understood. This is the aim of this thesis. This thesis contends that the very nature of oil and gas reserves, the processes of exploration and production, and the means that govern and characterise the transportation of petroleum overland and by sea is inherently geopolitical - that some core features of geopolitical theory and key geopolitical concepts are pivotal in determining the ontology and process of the international oil business. Indeed, so central has oil been to the advancement of industrial capacity, technology, warfare, transportation and economic prosperity of states since the 20th century, it could be argued that petroleum is the single largest determinant of the geopolitics that characterises the modern international system. In order to address the interrelationship and correlations between core aspects of the petroleum industry and causal geopolitical phenomena, I begin by advancing a framework of analysis that systematically binds key geopolitical features and concepts – specifically: Spatial Phenomena; Environmental Ontology; Territorial Access; Geopolitical Features; State and Non-state Concepts; and, Strategic Resources and Geopolitics - with examples of empirical findings revealed in subsequent chapters in the thesis. Fundamentally, this process works to assess causality and correlations between geopolitical phenomena such as space and distance, sovereignty, territory, boundaries, chokepoints, resource nationalism, transnationalism, resource security and conflict, and the features and processes inherent in petroleum reserves and the exploration, production and transportation of oil and gas. The framework is followed with a sequential analysis of the three empirical foci of the project: the ontology of oil and natural gas reserves; the planning and processes of exploration and production; and, the processes of the conveyance petroleum. I have concentrated my research to activities within Eurasia, which comprises the traditional continents of Europe and Asia, and the Indo-Pacific maritime realm, which extends eastwards from the Red Sea to the western Pacific Rim. After systematically assessing the empirical findings and examining key areas of geopolitical theory, I conclude that there is an identifiable and logical correlation between geopolitical phenomena, petroleum reserves, and the means to produce and distribute oil and gas between source and market.

Orientador: Paulina Setti Riedel / Banca: Cláudia Maria de Almeida / Banca: Maria Lúcia Marques / Resumo: A obtenção de informação sobre as condições da rede dutoviária representa papel primordial na operação dos dutos, não só com o propósito de manter a eficiência operacional, mas também, para a minimização dos riscos associados a possíveis acidentes, tanto decorrentes dos processos naturais quanto de causas antrópicas relacionadas ao uso e cobertura da terra. Neste sentido, o emprego de modelos matemáticos em estudos ambientais gera importantes contribuições científicas ao planejamento ordenado de uma área, uma vez que ajudam a entender o impacto das mudanças no uso e cobertura da terra e a prever alterações futuras nos ecossistemas. A área de estudo compreende porções dos municípios de Duque de Caxias, Belford Roxo e Nova Iguaçu e tem por objetivo realizar experimentos de mudanças da cobertura da terra em médio prazo (10 anos) para a faixa de dutos ORBEL. A modelagem realizada neste trabalho foi desenvolvida no software Dinamica-EGO, utilizando como entrada mapas classificados de cobertura da terra, obtidos através de imagens do satélite Landsat 5/TM, e variáveis espaciais para explicar as mudanças ocorridas na cobertura da terra. Para a calibração do modelo, utilizou-se o método de pesos de evidência, disponível no Dinamica-EGO, primeiramente categorizando-se os mapas de variáveis contínuas e, posteriormente, calculando-se os pesos de evidência. Valores positivos favorecem determinada transição, enquanto valores negativos indicam baixa probabilidade de transição, e valores próximos a zero não exercem efeito. A validação do modelo se deu pelo método de similaridade fuzzy, com decaimento exponencial. Os resultados mostram que, para os dois períodos analisados (1987-1998 e 1998-2010), a taxa de mudança para a transição "vegetação arbórea para outros" é bem maior do que para... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Reliable information about conditions of pipeline network represents a major role in the operation of pipelines, not only in order to maintain operational efficiency, but also to minimize the risks associated with possible accidents such as rupture of the ducts due to landslides or mudslides mass block, causing damage to humans and the environment. The use of mathematical models in environmental studies allows significant scientific contributions to the physical planning of an area, since they help to understand the impact of changes in land use and land cover and predict future trends of changes in ecosystems. The study area includes portions of the municipalities of Duque de Caxias, Nova Iguaçu, and Belford Roxo and aims to carry out experiments in land-cover changes in the medium-term (10 years) within the catchment area of ORBEL pipelines. The modeling performed in this work was developed using the software Dinamica-EGO, using as input classified land cover maps obtained from Landsat 5/TM satellite images as well as spatial variables to explain the observed changes in land cover. For the model calibration, we used the method of weights of evidence that is available at Dinamica-EGO. Initially, the maps of continuous variables were categorized according to discrete ranges, which were then employed for the calculation of the respective positive weights of evidence. Positive values foster certain transitions, while negative values indicate low probability of transition, and values close to zero have no effect on changes. Model validation was executed by means of the fuzzy similarity method using exponential decay. The results show that for the two study periods (1987-1998 and 1998-2010) the rate of change for the transition 'others to woody vegetation' is much higher than for the other transitions observed in the same... (Complete abstract click electronic access below) / Mestre