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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Valor da flexibilização e informação em desenvolvimento de campo por modulos / Value of information in development of oil filed by modules

Hayashi, Suzana Hisako Deguchi 15 August 2018 (has links)
Orientador: Denis Jose Schiozer / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias / Made available in DSpace on 2018-08-15T12:53:43Z (GMT). No. of bitstreams: 1 Hayashi_SuzanaHisakoDeguchi_M.pdf: 16467779 bytes, checksum: 4345ae4f5ff27ff7cee4722d4b305f55 (MD5) Previous issue date: 2006 / Resumo: O risco é inerente às várias fases da vida de um campo de petróleo, devido às incertezas, geológicas, econômicas e tecnológicas que influenciam o valor de um projeto. A aquisição de informações e a adição de flexibilidade na implantação de um projeto são os principais processos que permitem a mitigação dos riscos associados. O conceito de Valor da Informação (VDI) permite medir quantitativamente os benefícios resultantes da aquisição adicional de dados, que permite definir o projeto de desenvolvimento com mais precisão, podendo trazer modificações significativas em relação à concepção inicial (projeto conceitual). O conceito de Valor de Flexibilização (VDF) permite medir os benefícios de adicionar flexibilidade, por exemplo, no cronograma de implantação de um projeto, com o objetivo de possibilitar um melhor gerenciamento de reservatórios frente aos possíveis cenários. Os conceitos de VDI e VDF são usados neste trabalho para determinar o valor de adquirir novas informações para o projeto, considerando um atraso no cronograma causado pela flexibilização do momento de definição e aprovação do projeto básico. Uma técnica baseada nos Modelos Geológicos Representativos (MOR} e nas árvores de decisão é aplicada no processo de análise de decisão. Os resultados deste trabalho mostram que a metodologia proposta neste trabalho é aplicável em modelos de grande porte. Outras conclusões são que a relevância da aquisição de informações aumenta em cenários de preço de óleo mais baixo e que é importante analisar a redução de risco como variável adicional ao retomo financeiro no processo de decisão como o analisado neste trabalho / Abstract: The risk is inherent to several phases of a petroleum field development due to geological, economic and technological uncertainties, which influence the value of a project. The acquisition, of additional information and flexibility in the implementation, of a project are the main processes, which permit risk mitigation. The concept of Value of Information (VoI) permits to measure quantitatively the benefits of the new information that yield more accuracy in the definition of the development project and it can bring important modifications in comparison with the initial conception of the project. The concept of Value of Flexibility (VoF) allows measuring the benefits of flexibility in the implementation of a project yielding better reservoir management. The concepts of VoI and VoF are used in this work to determine the value of new information in a project, considering a delay in the schedule caused by the flexibility in the moment of definition and approval of the final project. A decision tree technique, associated to Geological Representative Models (GRM), is applied in the process of the quantification of the value of information and flexibility. Based on the results of this work, it is possible to conclude that: the methodology is useful for large fields; the relevance of information acquisition increases in low prices scenarios and; if is important to analyze risk mitigation in addition to financial gain in decision making processes like the one studied in this work / Mestrado / Engenharia de Petroleo / Mestre em Ciências e Engenharia de Petróleo
42

Management of Civil Infrastructure based on Structural Health Monitoring

Tonelli, Daniel 30 July 2020 (has links)
The interest in structural health monitoring (SHM) has grown considerably in the past half century, due to an explosive growth in the availability of new sensors, the development of powerful data analysis techniques, and the increasing number of civil infrastructure that are approaching or exceeding their initial design life. In SHM, we acquire observation on the behavior of a structure to understand its condition state, based on which we decide how to manage it properly. However, this optimistic view of SHM is in contrast with what happen in real life: infrastructure operators are typically skeptical about the capacity of monitoring to support decisions, and instead of following the suggestions provided by SHM, they often act based on their experience or common sense. The reason is that at present it is not fully clear how in practice to make decisions based on monitoring observation. To fill this gap between theory and practice, I propose to consider SHM as a logical process of making decision based on observation consisting of two steps: judgment, in which the condition state of structures is inferred based on SHM data, and decision, in which the optimal action is identified based on a rational and economic principle. From this perspective, a monitoring system should provide information that can improe he managers knoledge on he srcral condiion sae enough to allow them to make better decision on the structure management. Therefore, in designing a monitoring system, the design target must be the accuracy in the knowledge of structural state achieved analyzing the observations provided by it. However, when an engineer designs a monitoring system, the approach is often heuristic, with performance evaluation based on experience or common sense rather than on quantitative analysis. For this reason, I propose a performance-based monitoring system design, which is a quantitative method for the calculation of the expected performance of a monitoring solution a pre-posteriori and for checking it effectiveness in the design phase. It is based on the calculation of the monitoring capacity and the monitoring demand the counterparts of structural capacity and demand in the semi-probabilistic structural design, and like in structural design, the solution is satisfactory if the capacity is equal or better than the demand. The choice in whether to invest a limited budget on a monitoring system or in a retrofit is another critical choice for infrastructure managers: a retrofit work can increase the capacity and the safety of a structure, while sensors do not change the capacity, nor reduce the loads. Recently, the SHM-community has acknowledged that the benefit of installing a monitoring system can be properly quantified using the concept of Value of Information (VoI). A typical assumption in the VoI estimation is that a single decision-maker is in charge for decisions on both the investment in SHM for a structure, and its management based on SHM data. However, this process is usually more complex in the real world, with more individuals involved in the decision chain. Therefore, I formalize a rational method for quantifying the conditional value of information when two different actors are involved in the decision chain: the manager, who operate the structure based on monitoring data; and the owner, who chooses whether to install the monitoring system or not, before having access to these data. The results are particularly interested, showing that under appropriate conditions, the owner may be willing to pay to prevent the manager to use the monitoring system. Application to case studies are presented for all the research contribution presented in this doctoral thesis.
43

Optimization of production allocation under price uncertainty : relating price model assumptions to decisions

Bukhari, Abdulwahab Abdullatif 05 October 2011 (has links)
Allocating production volumes across a portfolio of producing assets is a complex optimization problem. Each producing asset possesses different technical attributes (e.g. crude type), facility constraints, and costs. In addition, there are corporate objectives and constraints (e.g. contract delivery requirements). While complex, such a problem can be specified and solved using conventional deterministic optimization methods. However, there is often uncertainty in many of the inputs, and in these cases the appropriate approach is neither obvious nor straightforward. One of the major uncertainties in the oil and gas industry is the commodity price assumption(s). This paper investigates this problem in three major sections: (1) We specify an integrated stochastic optimization model that solves for the optimal production allocation for a portfolio of producing assets when there is uncertainty in commodity prices, (2) We then compare the solutions that result when different price models are used, and (3) We perform a value of information analysis to estimate the value of more accurate price models. The results show that the optimum production allocation is a function of the price model assumptions. However, the differences between models are minor, and thus the value of choosing the “correct” price model, or similarly of estimating a more accurate model, is small. This work falls in the emerging research area of decision-oriented assessments of information value. / text
44

Analyse de connectivité et techniques de partitionnement de données appliquées à la caractérisation et la modélisation d'écoulement au sein des réservoirs très hétérogènes / Connectivity analysis and clustering techniques applied for the characterisation and modelling of flow in highly heterogeneous reservoirs

Darishchev, Alexander 10 December 2015 (has links)
Les techniques informatiques ont gagné un rôle primordial dans le développement et l'exploitation des ressources d'hydrocarbures naturelles ainsi que dans d'autres opérations liées à des réservoirs souterrains. L'un des problèmes cruciaux de la modélisation de réservoir et les prévisions de production réside dans la présélection des modèles de réservoir appropriés à la quantification d'incertitude et au le calage robuste des résultats de simulation d'écoulement aux réelles mesures et observations acquises du gisement. La présente thèse s'adresse à ces problématiques et à certains autres sujets connexes.Nous avons élaboré une stratégie pour faciliter et accélérer l'ajustement de tels modèles numériques aux données de production de champ disponibles. En premier lieu, la recherche s'était concentrée sur la conceptualisation et l'implémentation des modèles de proxy reposant sur l'analyse de la connectivité, comme une propriété physique intégrante et significative du réservoir, et des techniques avancées du partitionnement de données et de l'analyse de clusters. La méthodologie développée comprend aussi plusieurs approches originales de type probabiliste orientées vers les problèmes d'échantillonnage d'incertitude et de détermination du nombre de réalisations et de l'espérance de la valeur d'information d'échantillon. Afin de cibler et donner la priorité aux modèles pertinents, nous avons agrégé les réalisations géostatistiques en formant des classes distinctes avec une mesure de distance généralisée. Ensuite, afin d'améliorer la classification, nous avons élargi la technique graphique de silhouettes, désormais appelée la "séquence entière des silhouettes multiples" dans le partitionnement de données et l'analyse de clusters. Cette approche a permis de recueillir une information claire et compréhensive à propos des dissimilarités intra- et intre-cluster, particulièrement utile dans le cas des structures faibles, voire artificielles. Finalement, la séparation spatiale et la différence de forme ont été visualisées graphiquement et quantifiées grâce à la mesure de distance probabiliste.Il apparaît que les relations obtenues justifient et valident l'applicabilité des approches proposées pour améliorer la caractérisation et la modélisation d'écoulement. Des corrélations fiables ont été obtenues entre les chemins de connectivité les plus courts "injecteur-producteur" et les temps de percée d'eau pour des configurations différentes de placement de puits, niveaux d'hétérogénéité et rapports de mobilité de fluides variés. Les modèles de connectivité proposés ont produit des résultats suffisamment précis et une performance compétitive au méta-niveau. Leur usage comme des précurseurs et prédicateurs ad hoc est bénéfique en étape du traitement préalable de la méthodologie. Avant le calage d'historique, un nombre approprié et gérable des modèles pertinents peut être identifié grâce à la comparaison des données de production disponibles avec les résultats de... / Computer-based workflows have gained a paramount role in development and exploitation of natural hydrocarbon resources and other subsurface operations. One of the crucial problems of reservoir modelling and production forecasting is in pre-selecting appropriate models for quantifying uncertainty and robustly matching results of flow simulation to real field measurements and observations. This thesis addresses these and other related issues. We have explored a strategy to facilitate and speed up the adjustment of such numerical models to available field production data. Originally, the focus of this research was on conceptualising, developing and implementing fast proxy models related to the analysis of connectivity, as a physically meaningful property of the reservoir, with advanced cluster analysis techniques. The developed methodology includes also several original probability-oriented approaches towards the problems of sampling uncertainty and determining the sample size and the expected value of sample information. For targeting and prioritising relevant reservoir models, we aggregated geostatistical realisations into distinct classes with a generalised distance measure. Then, to improve the classification, we extended the silhouette-based graphical technique, called hereafter the "entire sequence of multiple silhouettes" in cluster analysis. This approach provided clear and comprehensive information about the intra- and inter-cluster dissimilarities, especially helpful in the case of weak, or even artificial, structures. Finally, the spatial separation and form-difference of clusters were graphically visualised and quantified with a scale-invariant probabilistic distance measure. The obtained relationships appeared to justify and validate the applicability of the proposed approaches to enhance the characterisation and modelling of flow. Reliable correlations were found between the shortest "injector-producer" pathways and water breakthrough times for different configurations of well placement, various heterogeneity levels and mobility ratios of fluids. The proposed graph-based connectivity proxies provided sufficiently accurate results and competitive performance at the meta-level. The use of them like precursors and ad hoc predictors is beneficial at the pre-processing stage of the workflow. Prior to history matching, a suitable and manageable number of appropriate reservoir models can be identified from the comparison of the available production data with the selected centrotype-models regarded as the class representatives, only for which the full fluid flow simulation is pre-requisite. The findings of this research work can easily be generalised and considered in a wider scope. Possible extensions, further improvements and implementation of them may also be expected in other fields of science and technology.
45

Web Sputnik Česká republika v kontextu alternativní mediální scény / Sputnik Czech Republic Website in the Context of Alternative Media Environment

Jaroš, Petr January 2021 (has links)
(English) The purpose of this diploma thesis was to analyze a role of Sputnik Česká republika (Sputnik Czech Republic) website as an information source in the ecosystem of the so-called alternative media. The main research method was quantitative content analysis. In the practical part of the work - using available metadata sraped with Outwit Hub -, this thesis described content of articles published on Sputnik Česká republika and other selected alternative media. Next, with the use of online marketing tools and other sources, it compared similarities of content and user behaviour. Next, it compared similarities of content and user behaviour on a sample of selected websites. The result of this was evaluation of possible importance of Sputnik Česká republika in the ecosystem of alternative media and pointing out some new elements and connections within this system. Possible usage of this thesis comprises follow-up research and education in fields of information and media literacy, especially in the issue evaluation of information sources.

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