Yes / Wave-seabed-pipelines interaction is of critical importance in the design of submarine pipelines. Previous studies mainly focus on investigating the characteristics of flow fields and hydrodynamics around a single pipeline. In this study, laboratory experiments and numerical simulations have been performed to examine the effect of burial depth and space between the centers of twin pipelines on the wave-seabed-twin pipelines interaction subject to waves. In the mathematical model, the Volume-Averaged Reynolds-Averaged Navier-Stokes (VARANS) equations are used to describe the wave motion in the fluid domain, while the seabed domain is described by using the Biot's poro-elastic theory. Numerical models are validated using these experimental measurements and available relevant experimental data. Experimental and numerical results indicate that the burial depth and relative position of twin pipelines can significantly affect the wave-averaged flow velocity field and the pore-water pressure distribution as well as effective stress.

The present study does not represent a general investigation of all the various divisions of the transportation phase of the petroleum industry but a very small segment of the industry, i.e., crude oil pipe lines. Rather than being an examination of the technical operations of the industry the study is directed towards a consideration of the instrumentalities of control of interstate pipe line facilities exercised at the hands of major or integrated companies.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

This thesis proposes the use of an Advanced Engineering Geographical Information System (AEGIS) for the improved design of onshore pipelines, from concept to operation. The system is novel in that it is function rather than discipline or software specific. The thesis statement has been developed, and an aim and set of research objectives identified (along with the success criteria for the evaluation of the system), based on a review of current pipeline design methods. Drawing on a design science research methodology (DSRM), the thesis proposes the development of the system as an artefact in order to validate the proposed constructs, models, methods and implementations. The thesis discusses the underlying issues of data interoperability, the application of open data standards, and the integration of computer aided design (CAD) and geographical information systems (GIS). These challenges are addressed in the thesis and demonstrated through the implementation of the system. To support the development of the system, research was undertaken in the fields of pipeline engineering, environmental engineering and engineering design. As part of this research, a number of peer-reviewed journal papers were published, and conference papers presented in Kampala, Houston, London and Split. These papers covered the key fields contained in the thesis including, fluid mechanics, bio-systems engineering, environmental engineering, CAD/GIS integration (CGI), and the application and development of geospatial pipeline data models. The thesis concludes that the approach is valid, offering significant improvement across all fields compared to the current method of pipeline design. By taking a functional approach to the challenges of the design of pipelines, a system has been developed that addresses the requirements of the pipeline engineer, environmental engineer and engineering designer. The system enables the user to select the software of their choice, thereby reducing the problems associated with data interoperability, retraining and system integration. The sharing of data and outputs from analysis carried out within the system, provides an integrated approach, which can subsequently be used for the integrity management of the pipeline during the operational phase of the project. The scope for further development of this approach to pipeline design is also discussed. In addition to the inclusion of further engineering and environmental analysis, there is the potential for using the system for the design of subsea pipelines.

Le détecteur LHCb est l'une des quatre expériences de physique des particules de la nouvelle chaîne d'accélération LHC du CERN. Afin de réduire la quantité de données destinée au stockage, un dispositif de sélection en ligne est mis en place. L'unité de décision au niveau 0 (L0DU) est le système central du premier niveau de déclenchement. LODU est un circuit imprimé 16 couches intégrant des composants de haute technologie de type FGPA et des liaisons optiques à 1,6 Gbit/s. Le traitement est implémenté en utilisant une architecture pipeline synchrone à 40 MHz. L0DU applique un algorithme de physique simple pour calculer sa décision et réduire le flot de données de 40 MHz à 1 MHz pour le prochain niveau de sélection. Le traitement interne se compose d'un traitement partiel des données (PDP) et d'une partie dédiée à la définition de l'algorithme de sélection (TDU). Le TDU est flexible et permet de reconfigurer entièrement les conditions de déclenchement sans re-programmation des FGPA

[pt] A tendência da produção offshore do petróleo é crescente. O transporte do óleo nestes ambientes frios (águas profundas) ocasiona a perda de solubilidade e precipitação das parafinas de alto peso molecular. A deposição de parafinas nas paredes internas das linhas é um problema crítico para o transporte do óleo, causando o bloqueio parcial ou total da linha, um incremento da potência de bombeamento e elevados custos de manutenção que são proporcionais ao aumento da lâmina de água. A pesquisa bibliográfica realizada neste trabalho revela que ainda existem discordâncias entre os pesquisadores sobre a relevância de cada um dos mecanismos de deposição de parafina conhecidos. O melhor entendimento dos mesmos resultaria em previsões mais acuradas das taxas de deposição que seriam muito importantes para orientar programas de manutenção e o projeto de novas linhas. A filosofia do presente trabalho é realizar experimentos simples, com propriedades de fluido conhecidas e condições de contorno bem controladas procurando um melhor entendimento da importância e relevância de cada um dos mecanismos de deposição. Para este fim, foram realizadas experiências de visualização do fenômeno de deposição para uma mistura de óleo-parafina escoando em regime laminar, submetida a diferentes condições de temperatura. Experiências feitas com cristais de parafina precipitados em suspensão mostraram que é necessário um fluxo de calor negativo para produzir deposição. Para fluxos de calor zero e positivo não foi visualizada deposição alguma. Adicionalmente, para condições de fluxo de calor negativo, foram realizadas medições da evolução temporal da espessura da camada depositada tendo como variáveis, diferentes números de Reynolds e gradientes de temperatura. Os perfis de deposição obtidos das experiências realizadas são informação importante e original que podem ser utilizadas para validação de modelos de simulação numérica. / [en] Offshore crude oil production is steadily growing. Oil transport in these cold environments (deep water) causes the precipitation of the heavy organic crude oil components like waxes. Wax deposition at the inner wall of pipelines is a serious problem in crude oil transportation causing the partial or total plugging of pipelines, increase in pumping energy and a high cost of maintenance that is proportionally greater as development depth increases. A literature research conducted in the present work leads to the conclusion that the relative importance of the wax deposition mechanisms is still misunderstood. The importance of this knowledge will result in more accurate prediction of paraffin deposition rates that would be very important to sub sea pipelines maintenance and design. The philosophy of this work is to make simple experiments with known fluid properties and well controllable conditions trying to understand the importance and relevance of each known fouling mechanism. Hence, wax deposition experiments were performed in laminar flow for different temperature conditions with a single-phase paraffin-oil mixture, having the particle migration visualization in mind. Experiments with oil mixture injection temperature below the Wax Appearance Point (with wax crystals flowing) have shown that it is necessary a negative heat flux to produce significant deposition. For positive and zero heat fluxes there was no deposition visualized. Also, the unsteady fouling state for negative heat flux was followed and their temporal deposition profiles measured for different Reynolds and temperature conditions. Those temporal and dimensional deposition profiles are original important information to be compared with numerical simulation.

O presente trabalho versa sobre o termo de atrito em escoamento transitório em condutos forçados, partindo de uma modelação matemática da tensão de cisalhamento transiente, usando conceitos do princípio da entropia máxima. Usa-se a modelação deste termo de atrito na análise do transitório hidráulico, comparando-se com dados experimentais já publicados de um sistema Reservatório-Tubo-Válvula. / This report contains a friction term for hydraulic transient in closed conduits. We use a mathematical model for the shear stress, derived by principle of maximum entropy. Then, we use this friction term for an analysis in a system reservoir-tube-valve, comparing our results with anothers already published in the literature.

Sistemas de dutos correspondem atualmente ao modo mais eficaz para o transporte de grandes quantidades de fluidos líquidos e gasosos por longas distâncias. Dutos são utilizados pela Indústria Petrolífera para o transporte de petróleo e de seus produtos derivados. O presente trabalho aborda o scheduling de distribuição dutoviária de um sistema que opera com um duto que transporta produtos de uma refinaria para depósitos com localizações geográficas distintas através de modelos de programação matemática. O sistema é composto pela Refinaria do Planalto (REPLAN) da Petrobras localizada em Paulínia (SP). A ela é conectado um duto (OSBRA) que se estende por cerca de 1000 quilômetros. O maior detalhamento do modelo matemático para operações dutoviárias desenvolvido por Rejowski Jr. (Dissertação de Mestrado, EPUSP, São Paulo, 2001) se torna primordial nessa complexa operação logística. Um fator de extrema importância é a contaminação dos produtos dentro da linha dutoviária. Desta forma, são desenvolvidas restrições especiais que impõem paradas aos segmentos do duto somente quando os mesmos não possuem interfaces. Estas restrições fazem com que a formulação proposta encontre a solução ótima do problema proposto. O aprimoramento destas formulações se torna fundamental, pois os modelos gerados possuem um número elevado de decisões a serem otimizadas. Relações lógicas envolvendo o estoque inicial nos depósitos e na linha dutoviária e a demanda de cada um dos produtos são propostas. Estas relações melhoram o desempenho computacional para os modelos propostos em cenários de demandas altas. Posteriormente, as restrições especiais de contaminação dos produtos e as relativas ao atendimento das demandas nas bases de distribuição são relaxadas e transformadas em penalidades na função objetivo. Estas penalidades aumentam o esforço de resolução dos modelos e ao mesmo tempo possuem grande influência nos resultados operacionais do sistema. Outro fator de extrema importância para o scheduling de operações dutoviárias é a sua representação em tempo contínuo. Adicionalmente, esta representação faz com que a incorporação de restrições hidráulicas de maneira simplificada seja possibilitada. Desta forma, uma estratégia simplificada e eficaz para se determinar a vazão do duto, envolve incluir a curva de rendimento das estações de bombeamento. Esta formulação, que é modelada como um MINLP (Mixed Integer Non Linear Programming), é comparada com uma formulação MILP (Mixed Integer Linear Programming) em tempo discreto com vazões e rendimentos fixos proposta por Rejowski Jr. e Pinto (Computers and Chemical Engineering, 2004, v.28/8 p.1511-1528). Foi mostrado que a presente formulação forneceu soluções de melhor qualidade. A formulação MILP em tempo discreto é caracterizada como um caso particular da presente formulação proposta. A formulação MINLP sofre forte influência do número de intervalos de tempo que a compõem e este fator deve sempre ser considerado para que a melhor solução possa ser encontrada em tempo computacional factível. Esta formulação ainda é aplicada com sucesso a um caso sob diversas configurações de bombeamento com diferentes custos unitários e curvas de rendimento. Duas formulações que consideram a programação de operações de dutos com a incorporação dos aspectos hidráulicos calculados de maneira rigorosa são apresentadas. A primeira delas resulta em um modelo MINLP e considera variações na duração dos intervalos de tempo e na vazão operacional do sistema. Uma segunda formulação apresentada como um modelo MILP é desenvolvida. Resultados computacionais para ambos os modelos são apresentados, assim como as suas soluções geradas são discutidas. O impacto de variações no relevo do sistema dutoviário é analisado. Foram detectadas alterações na vazão de operação do sistema dutoviário, na escolha dos intervalos de tempo em que o sistema é ativado, no rendimento das estações de bombeamento e no tempo total de operação do sistema. Posteriormente, em um outro exemplo, é mostrado que variações no relevo também podem alterar a seqüência dos produtos alimentados pela refinaria ao duto. Finalmente, as formulações têm os seus resultados comparados aos de modelos com considerações hidráulicas simplificadas, cujos resultados podem levar a soluções subótimas e até mesmo inviáveis. / Pipeline systems correspond nowadays to the most efficient mode for the transportation of large amounts of liquid and vapor products for long distances. Pipelines are utilized by the Petroleum Industry to transport petroleum and its product derivatives. The present work addresses the scheduling of pipeline distribution of a system that operates with a pipeline that transports products from a refinery to depots at different geographical locations by mathematical programming models. The system is composed by the Planalto Refinery (REPLAN) from Petrobras. A pipeline (OSBRA) is connected to the refinery that extends for approximately 1000 kilometers. A higher level of detail in the mathematical model for pipeline operations developed by Rejowski Jr. (MS Dissertation, EPUSP São Paulo, 2001) becomes essential in this complex logistic operation. A factor of extreme importance is product contamination inside the pipeline. Therefore, special constraints are developed that impose the segments of the pipeline to operate continuously when they do not contain interfaces. These constraints help the proposed formulation to find the optimal solution of the problem. The improvement of logical formulations becomes paramount because the generated models encompass a large number of decisions to be optimized. Logical relations involving the initial inventory at the depots and at the pipeline, as well as the demands for each product are proposed. These relations improve the computational performance of the proposed models in scenarios of high-demand. Then, the special constraints and the demand satisfaction at the depots at the end of the operational horizon are relaxed and added as penalties in the objective function. These penalties increase the solution effort of the proposed models and at the same time have great influence on the operational results of the system. Another factor of extreme importance for the pipeline operation scheduling is its continuous time representation. Additionally, this representation enables the models to incorporate simplified hydraulic constraints. Therefore, a simplified and efficient strategy to determine the pipeline flow rate is to include the yield curves of the pumping stations. This formulation, that is modeled as an MINLP (Mixed Integer Non Linear Programming), is compared to an MILP (Mixed Integer Linear Programming) with discrete time and fixed flow and yield rates proposed by Rejowski Jr. and Pinto (Computers and Chemical Engineering, 2004, v.28/8 p.1511-1528). It is shown that the present formulation provides better quality results. The MILP formulation with discrete time is characterized as a particular case of the proposed formulation. The MINLP is greatly influenced by the number of time intervals that compose it and this factor has always to be considered so that the best solution can be found with feasible computational effort. This formulation is also applied to a case with several pumping station configurations with different unit costs and yield curves. Two formulations that consider the scheduling of pipeline operations with the incorporation of the hydraulic aspects calculated rigorously are presented. The first one results in an MINLP model and considers variations on the time interval durations and in the pipeline flow rate. A second MILP formulation is developed. Computational results for both models are shown as well as the generated solutions discussed. The impact of variations on the topographical profile of the pipeline system is analyzed in the obtained results by the models. Changes in the flow rate of the pipeline, in the decision of the time intervals that the system is activated, in the pumping station yields and in the time interval durations were detected. Then, in another example it is shown that the changes in the topographical profile can alter the sequence of products sent by the refinery to the pipeline. Finally, both formulations have their results compared to models with simplified hydraulic considerations, whose results can lead to suboptimal and even to infeasible solutions.

Les canalisations sont largement employées pour le transport de fluides et de gaz, car c'est le mode d'acheminement le plus économique actuellement. Le souci des exploitants est d'assurer la maintenance des réseaux pour préserver la sécurité des populations, notamment dans le cas de gaz inflammables ou explosifs. Néanmoins, plusieurs accidents ont été constatés, qui sont généralement dus à la rupture de ces canalisations comportant des défauts, tels que : la corrosion, fissures dans les joints soudés et les agressions externes. Cette thèse est relative aux problèmes liés aux agressions externes des structures sous pression. Ces agressions externes sont considérées être réalisées à faible vitesse de déformation et conduisent à des défauts de type : enfoncements ou éraflures, ou aussi la combinaison des deux (enfoncements + éraflures). Ce travail a pour objectif de proposer une étude complète, à la fois expérimentale et numérique, sur le comportement d'une canalisation sous pression contenant les défauts décrits ci-dessus. Il se base sur l'extension de l'analyse limite et la mécanique de rupture d'entaille pour les enfoncements seuls et les défauts dits combinés. La vérification de la validité de quelques règles empiriques sur l'acceptabilité d'un enfoncement sera effectuée simultanément. Deux critères de rupture ont été proposés : le critère de rupture ductile d'Oyane dans le cas d'un enfoncement seul et la mécanique de rupture d'entaille en utilisant la méthode volumétrique associée à la triaxialité des contraintes dans le cas d'un défaut combiné (enfoncement + éraflure) / The pipelines are widely used to transport fluid and gas because they are now, the cheapest mode of transport. The concern of operators is to ensure the maintenance of networks in order to preserve the security of reported, which are usually due to failure of these lines with defects, such as : corrosion, cracks in welds and external interferences. This thesis is related to external interferences for structures under internal pressure. These external interferences are considered to be made at low strain rate and leads to defects of types : dents or gouges or a combinaison of both (dents + gouges). The aim of this work is to propose a comprehensive study, both experimental and numerical of behaviour of a pipeline under pressure containing the defects described above. It is based on extending of the theory of the limit analysis and notch fracture mechanics for dents as defect and combination of dents and gouges. The verification of the validity of some empirical rules on the acceptability of dent depth will be made simultaneously. Two failure criteria were proposed : the Oyanes's ductile fracture criterion in the case of a dent and notch fracture mechanics using volumetric method associated with stress triaxiality in the case of a combined defect (dent+ gouge)

Les travaux effectués dans le cadre de cette thèse portent sur l’analyse de la vulnérabilité sismique des canalisations enterrés d’un réseau d’alimentation en eau potable (AEP). Ceci afin de disposer d’outils fiables permettant le diagnostique et le ciblage des interventions à même de réduire le risque de perte dans ce réseau en cas de tremblement de terre. Un exemple d’application des concepts développés dans cette étude porte sur la ville de Blida qui possède une infrastructure économique importante et dont le réseau constitue un échantillon représentatif des réseaux d’AEP des villes Algériennes. Ce réseau a été mis sous Système d’Information Géographique (SIG) afin de permettre une lecture aisée des différents résultats. Deux approches ont été utilisées pour appréhender ce problème de vulnérabilité, une approche statistique et une approche numérique. L’approche statistique utilise le retour d’expérience sismique comme base et a permis de d’identifier les paramètres ayant une influence sur le comportement sismique d’un tronçon de canalisation. Des coefficients de pondération ont été déterminés à partir d’analyse de données post sismique ce qui a conduit à la définition d’un indice de vulnérabilité. Ce dernier permet une classification des canalisations enterrées en fonction de leur vulnérabilité. Des courbes de vulnérabilité sont également proposées. L’approche numérique utilise le concept de macroéléments pour modéliser le comportement d’une canalisation enterrée sous sollicitation sismique en considérant l’interaction sol-conduite. Les champs proches et lointains sont considérés à travers un macroélément, de même que le comportement du joint entre deux tronçons. Une stratégie de calcul a été élaborée et testée sur un exemple de conduite. Les résultats obtenus décrivent le comportement réel des tuyauteries lors d’un tremblement de terre. Ils permettent d’affiner les coefficients de l’approche statistique et les calculs pourront être utilisés pour construire les courbes de vulnérabilité / Within this work, seismic vulnerability of buried pipelines is investigated. This is to provide reliable tools allowing the diagnosis and the targeting of interventions that can reduce the risk of loss in the water network in case of an earthquake. A case study focused on the city of Blida is analyzed in order to apply the developed concepts herein. Blida has a large economic infrastructure and its water network is a representative sample of the water supply systems of Algerian cities. This network was put under a Geographic Information System (GIS) to allow easy interpretation of the different results. Two approaches were used to study this vulnerability problem, a statistical method and a numerical method. Thestatistical approach uses the seismic feedback experiences as a basis to identify the parameters that have an influence on the seismic behavior of a pipe. Weighting factors are determined too, allowing the definition of a vulnerability index. This one enables the classification of buried pipelines according their vulnerability. Vulnerability curves are also proposed. The numerical approach uses the concept of macro element to model the behavior of a buried pipeline under seismic solicitation taking into account the soil structure interaction. Far field and near field are considered through the use of a maco element, another macoelement is developed for the joint between two pipes. A computational strategy is developed and tested on a sample. The results describe the behavior of pipes during an earthquake. They allow a refinement of the statistical approach coefficients and the methodology can be used to build vulnerability curves.