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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.
61

Estudo do escoamento bifasico em risers em movimento na produção maritima de petroleo em aguas profundas / Study of two-phase flow in moving risers for offshore petroleum production in deep waters

Silva, Elinaldo Santos 04 May 2006 (has links)
Orientador: Sergio Nascimento Bordalo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-13T17:08:45Z (GMT). No. of bitstreams: 1 Silva_ElinaldoSantos_M.pdf: 5134236 bytes, checksum: 2676ce4cb7784fed1bc7b1d622f6cc62 (MD5) Previous issue date: 2006 / Resumo: O escoamento vertical bifásico é de suma importância na produção de petróleo, uma vez que os reservatórios petrolíferos produzem óleo e gás simultaneamente, e estes devem fluir até a superfície submarina através de poços, e destes até a plataforma de produção através de dutos verticais (risers) no mar. Ao longo de seu escoamento, a mistura pode desenvolver vários padrões de fluxo. Os padrões identificados no escoamento vertical são bolhas, golfadas, transição e anular, e essas configurações físicas apresentam características próprias que exigem modelagens distintas, apresentando relações particulares de perda de carga em função da vazão. A caracterização correta do padrão, sob dadas condições operacionais, é fundamental para modelar a dinâmica do escoamento e determinar a relação entre perda de carga e vazão. Na literatura, estudos sobre o estabelecimento dos padrões de fluxo foram realizados com água e ar, e estão restritos ao caso de dutos estáticos, enquanto que os risers de produção estão em constante movimento devido à ação das ondas, das correntezas e da plataforma de produção. Sendo assim, a aplicação destes mapas nas condições de produção em águas profundas são questionáveis. O presente trabalho é importante para a produção de óleo e gás em águas profundas, porque aborda as condições de movimento de dutos verticais longos e esbeltos sob oscilações. Nestes dutos, as forças decorrentes do movimento do mar e da plataforma de produção geram sobre o duto um movimento transversal alternado. Para se estudar esse efeito, um aparato experimental foi construído em escala de laboratório, com um duto flexível de 8,0 m de comprimento e 25,4 mm de diâmetro, provido de um sistema de oscilação e de injeção de água e ar para se estudar os padrões de fluxo vertical ascendente bifásico em dutos em movimento. / Abstract: The two-phase vertical flow is of utmost importance for petroleum production, since petroleum reservoirs produce oil and gas simultaneously, which must flow up to the undersea surface through wells, and from these to the production platform through vertical pipes (risers) in the sea. Throughout the flow, the mixture of oil and gas may develop several flow patterns. The flow patterns identified in the vertical flow are bubbles, slugs, churn and annular, and these physical configurations present specific characteristics that demand distinct modeling and, presenting particular relations of head loss as function of the flow rate. The correct characterization of the flow patterns, under given operational conditions, is fundamental to the modeling of the dynamics of the flow and to determine the relation between head loss and flow rate. In the literature, studies on the establishment of the flow patterns had been carried with water and air, and were restricted to the case of static pipes, while production risers are in constant movement due to the action of waves, sea currents and the displacement of the production platform. Therefore, the application of these static maps for the conditions of production in deep waters is questionable. The present work is important for the production of oil and gas in deep waters, because it takes into account the oscillatory movement of long and slender vertical pipelines. In these pipes, the forces resulting from of the movements of the sea and the production platform generate an alternated transversal movement on the pipeline. An experimental apparatus built in the laboratory scale to study this effect, with a flexible duct of 8,0 m of length and 25,4 mm of diameter, attached to a system of oscillation and connected to an injection nozzle of water and air to study the patterns of two-phase vertical upward flow in moving pipes. / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo
62

A study on well design and integrity for deepwater exploratory drilling in Brazilian Equatorial Margin. / Um estudo sobre o projeto e integridade de poços para perfuração exploratória em águas profundas na Margem Equatorial Brasileira.

Manuel Sebastian Salazar Ruiz 12 June 2018 (has links)
Drilling operations in deepwater (DW) or ultra-deepwater areas, even more in exploratory frontiers, have been increasingly challenging due to the operational complexities and limited available data about the subsurface conditions. In this sense, enhancing safety and minimizing the likelihood of losing well integrity and damage to the environment is a currently essential objective relating to offshore drilling activities. Hence, deepwater well designs should advance to safely meet the challenges related to the progression of well and water depths. The safe construction of these wells requires the application of suitable well design considerations that include well integrity approaches to reduce the risk of an unintended release of formation fluids (oil, gas or water) to the environment during the deepwater drilling operations, in other words a \"Blowout\" occurrence. In this study it is proposed two deepwater well architectural designs, limited to drilling stage, that safely accomplish the well targets and facing several deepwater well complexities, e.g. narrow operating envelopes. Thus, well logging and geological data of two actual pioneer wells drilled in deep and ultradeep water zones in Ceará Basin are used as a basis to construct and assess the drilling operating envelopes, to define the casing shoe depths and well barrier envelope. Furthermore, it is introduced the application of at least two independent Barrier Integrated Sets (BISs) to ensure the well integrity during the 4th phase drilling of the proposed well architectures, as it has recently been required in Brazil by the National Petroleum Agency (ANP) through \"Well Integrity Management System\" (SGIP for its acronym in Portuguese). / As operações de perfuração em áreas de águas profundas ou ultra profundas, ainda mais nas fronteiras exploratórias, têm sido cada vez mais desafiadoras devido às complexidades operacionais e aos limitados dados disponíveis sobre as condições do subsolo. Nesse sentido, aumentar a segurança e minimizar a probabilidade de perder a integridade do poço e os danos ao meio ambiente são objetivos essenciais atualmente relacionados às atividades de perfuração offshore. Portanto, os projetos de poços em águas profundas devem avançar para enfrentar com segurança os desafios associados à progressão do poço e das profundidades da água. A construção segura desses poços requer a aplicação de considerações de projeto adequadas que incluam abordagens da integridade do poço para reduzir o risco de liberação não intencional de fluidos de formação (óleo, gás ou água) para o ambiente durante as operações de perfuração em águas profundas, em outras palavras a ocorrência de \"Blowout\". Neste estudo, são propostos dois projetos arquiteturais de poços em águas profundas, limitados à etapa de perfuração, que cumprem com segurança os objetivos do poço e enfrentam várias complexidades de poços em águas profundas, por exemplo janelas operacionais estreitas. Assim, dados geológicos e de perfilagem de dois poços pioneiros perfurados nas zonas de águas profundas e ultra profundas da Bacia do Ceará são usados como base para a construção e avaliação da janela operacional, para definir as profundidades da sapata do revestimento e do conjunto das barreiras do poço. Além disso, é introduzida a aplicação de pelo menos dois Conjuntos Solidários de Barreiras (CSBs) independentes para garantir a integridade do poço durante a perfuração da 4ª fase das arquiteturas dos poços propostos, como tem sido recentemente exigido no Brasil pela Agência Nacional do Petróleo (ANP), através do \"Sistema de Gerenciamento de integridade de Poços\" (SGIP).
63

Sequence stratigraphic characterisation of petroleum reservoirs in Block 11b/12b of the Southern Outeniqua Basin

Nfor, Nformi Emmanuel January 2011 (has links)
Magister Scientiae - MSc / The main purpose of this study was to identify and characterize the various sand prone depositional facies in the deepwater Southern Outeniqua Basin which generally tend to form during lowstand (marine regression) conditions producing progradational facies. It made use of sequence stratigraphy and turbidite facies models to predict the probable location of deepwater reservoirs in the undrilled Southern Outeniqua Basin using data from basin margin Pletmos Basin and the deepwater Southern Outeniqua Basin. Basin margin depositional packages were correlated in time and space with deepwater packages. It was an attempt at bridging the gap between process-related studies of sedimentary rocks and the more traditional economic geology f commercial deposits of petroleum using prevailing state-of-the-art in basin analysis. It enabled the most realistic reconstructions of genetic stratigraphy and offered the greatest application in exploration. Sequence stratigraphic analysis and interpretation of seismics, well logs, cores and biostratigraphic data was carried out providing a chronostratigraphic framework of the study area within which seismic facies analysis done. Nine (9) seismic lines that span the shallow/basin margin Pletmos basin into the undrilled deepwater Southern Outeniqua basin were analysed and interpreted and the relevant seismic geometries were captured. Four (4) turbidite depositional elements were identified from the seismic lines: channel, overbank deposits, haotic deposits and basin plain (basin floor fan) deposits. These were identified from the relevant seismic geometries (geometric attributes) observed on the 2D seismic lines. Thinning attributes, unconformity attributes and seismic facies attributes were observed from the seismic lines. This was preceded by basic structural analyses and interpretation of the seismic lines. according to the structural analysis and interpretation, deposition trended NW-SE and NNW-SSE as we go deepwater into the Southern Outeniqua basin. Well logs from six (6) of the interpreted wells indicated depositional channel fill as well as basin floor fans. This was identified in well Ga-V1 and Ga-S1 respectively. A bell and crescent shape gamma ray log signature was observed in well Ga-V1 indicating a fining up sequence as the channel was abandoned while an isolated massive mound-shape gamma ray log signature was observed in Ga-S1 indicating basin plain well-sorted sands. Core analyses and interpretation from two southern-most wells revealed three (3) facies which were derived based on Walker‘s 1978, turbidite facies. The observed facies were: sandstone, sand/shale and shale facies. Sequence stratigraphic characterisation of petroleum reservoirs in block 11b/12b of the Southern Outeniqua Basin. Cores of well Ga-V1 displayed fine-grained alternations of thin sandstone beds and shales belonging to the thin-bedded turbidite facies. This is typical of levees of the upper fan channel but could easily be confused with similar facies on the basin plain. According to Walker, 1978 such facies form under conditions of active fan progradation. Ga-S1 cores displayed not only classic turbidite facies where there was alternating sand and shale sections but showed thick uninterrupted sections of clean sands. This is typical of basin plain deposits. Only one well had biostratigraphic data though being very limited in content. This data revealed particular depth sections and stratigraphic sections as having medium to fast depositional rates. Such rates are characteristic of turbidite deposition from turbidity currents. This study as well as a complementary study by Carvajal et al., 2009 revealed that the Southern Outeniqua basin is a sand-prone basin with many progradational sequences in which tectonics and sediment supply rate have been significant factors (amongst others such as sea level change) in the formation of these deepwater sequences. In conclusion, the Southern Outeniqua basin was hereby seen as having a viable and unexplored petroleum system existing in this sand prone untested world class. / South Africa
64

Crisis strategies in BP's Deepwater Horizon response : An image repair and situational crisis communication study

Johansson, Mikael January 2017 (has links)
The BP Deepwater Horizon crisis in 2010 was one the largest catastrophes in the history of the oil industry. BP was sued over the disaster, and lost several billion dollars. This study examines the crisis response strategies and/or image repair strategies, which can be found in BP's press releases following the Deepwater Horizon crisis. In particular, the study looks closer at what established crisis communication strategies could be discerned in the material, and how they are used discursively. The theories used were the Image Repair Theory (IRT) and the Situational Crisis Communication Theory (SCCT). The results show that BP utilized a number of different established crisis response strategies and/or image repair strategies in their crisis communication work in the press releases. These strategies were concern, corrective action, ingratiation, transcendence, differentiation, denial, shifting the blame/scapegoating, defeasibility, compassion and attacking the accuser. They were used discursively by the CEO by expressing sympathy, promising that a similar event will never happen again, by stating appreciation for and praising the leadership of the U.S. President and public sector. What is more, it is used by describing in detail how the solution process progresses, by stating what the causes of the crisis were, by describing other involved actors' lack of taking responsibility and by establishing a fraud hotline. The main conclusions of the study are that BP used several crisis strategies in their press release s, though rather inconsistently. Additionally, BP used the strategies in an ambiguous manner, and changed strategies over time. Lastly, one main conclusion is also that a company is prepared to utilize crisis communication strategies in their practical communications work, though not entirely in the way prescribed by the theories.
65

Effects of the Deepwater Horizon Oil Spill on Deep Sea Fishes

Leary, Arianne Ella 01 January 2015 (has links)
The Deepwater Horizon Oil Spill (DWH) released about 4.4 million barrels of crude oil into the Gulf of Mexico (GOM), making it one of the largest oil spills in U.S. history. Additionally, the depth of the spill (i.e., 1500 meters) created a unique research opportunity because most oil spills occur at the surface and affect coastal rather than deepwater habitats. Polycyclic aromatic hydrocarbons (PAHs) are the most toxic components of oil, and are often the focus of oil exposure studies. PAHs are quickly metabolized by vertebrates; therefore, indicators of biological responses to PAH exposure (PAH “biomarkers”) such as the levels of PAH detoxification enzymes and the resulting metabolites are commonly used to examine oil exposure. This study measured multiple PAH biomarkers including hepatic activity of the PAH detoxification enzymes cytochrome P4501a1 (CYP1A) and glutathione-S-transferase (GST), as well as biliary PAH metabolites in deep sea sharks and bony fishes from areas affected by the Deepwater Horizon Oil Spill. Samples were collected from 2011-2013 from seven species of sharks, with special focus on the four most abundant deep sea species: Centrophorus niakang, Centrophorus cf granulosus, Squalus cubensis and Squalus cf mitsikurii. Overall enzyme activity was low in these sharks, yet it was higher in oiled sites compared to reference locations. Additionally some species showed declining CYP1A activity since the time of the oil spill, suggesting exposure to CYP-inducing compounds during the beginning of the survey period. Last, PAHs of a petrogenic nature were more abundant in oiled sites compared to reference locations. Overall, this project provides the much need biomarker data for sharks as well as insight on exposure and metabolism of PAHs in deep sea sharks after the DWH.
66

Deepwater Channel Systems in the Orca and Choctaw Basins, Northern Gulf of Mexico

Treiber, Katie M. 28 June 2017 (has links)
No description available.
67

The impact of social media on crisis communication

Gannon, Patrick J. 01 January 2011 (has links)
The purpose of this study was to examine the impact of social media on crisis communication. To evaluate this impact, a case study method was utilized examining the crisis communication response of the Deepwater Horizon Oil Spill on April 20, 2010. This study focused on the response of the responsible party, British Petroleum, and the general public over three social media: Facebook, Twitter, and blogs. Through extensive analysis of both the company's and public response to the Gulf spill, nine implications were identified regarding social media's influence on crisis communication. These implications highlighted the potential for organizations to build interpersonal relationships with its publics. These relationships were found to be crucial in times of crises. The implications of this study also pointed to interactivity, using a "human voice," trust, and credibility as crucial factors in building these relationships and leading an effective crisis response across social media. This study also noted the new stress for organization's to respond quickly to crises as a result of instant news brought by social media. Implications of this study also highlighted social media's influence on individuals becoming contributing members of a crisis response. While social media has influenced the practice of crisis communication in many ways, this study found that the principles and ethics of the field have remained the same. In conclusion, analysis suggests that BP neglected using social media in its crisis response, a channel which has entered the mainstream of crisis communication. As a result, this study recommends the use of social media before, during, and after a crisis to ensure the welfare of a company and its relationship with its publics.
68

A Mixed-Methods Content Analysis Case Study of Frames and Ideologies in Mainstream Environmental News

Kelvin, William 02 December 2019 (has links)
No description available.
69

Influence of Petroleum Deposit Geometry on Local Gradient of Electron Acceptors and Microbial Catabolic Potential

Singh, Gargi 17 April 2012 (has links)
A field survey was conducted following the Deepwater Horizon blowout and it was noted that resulting coastal petroleum deposits possessed distinct geometries, ranging from small tar balls to expansive horizontal oil sheets. A laboratory study evaluated the effect of oil deposit geometry on localized gradients of electron acceptors and microbial community composition, factors that are critical to accurately estimating biodegradation rates. One-dimensional top-flow sand columns with 12-hour simulated tidal cycles compared two contrasting geometries (isolated tar "balls" versus horizontal "sheets") relative to an oil-free control. Significant differences in the effluent dissolved oxygen and sulfate concentrations were noted among the columns, indicating presence of anaerobic zones in the oiled columns, particularly in the sheet condition. Furthermore, quantification of genetic markers of electron acceptor and catabolic conditions via quantitative polymerase chain reaction of dsrA (sulfate-reduction), mcrA (methanogenesis), and cat23 (oxygenation of aromatics) genes in column cores suggested more extensive anaerobic conditions induced by the sheet relative to the ball geometry. Denaturing gradient gel electrophoresis similarly revealed that distinct gradients of bacterial communities established in response to the different geometries. Thus, petroleum deposit geometry impacts local redox and microbial characteristics and may be a key factor for advancing attenuation models and prioritizing cleanup. / Master of Science
70

Étude des procédés discursifs de légitimation mobilisés par l'état et une entreprise privée dans un contexte de gestion de crise-À partir du cas Deepwater Horizon au large de la Louisiane - approche sociopolitique

Heni, Amira 20 April 2018 (has links)
Notre étude relève d’une analyse exploratoire fondée sur une étude de cas. En partant d’un exemple de débat articulé autour d’un enjeu public, en l’occurrence la responsabilité sociale d’entreprise (RSE), nous appréhendons le discours comme un instrument de pouvoir déployé par des acteurs en position conflictuelle. Nous prenons comme un cas d’étude la crise écologique provoquée par British Petroleum (BP) au large du Golfe de Mexique le 20 avril 2010. Pour sélectionner notre corpus, nous avons désigné deux populations cibles de discours, en l’occurrence le discours tenu par le gouvernement américain (discours d’Obama) et le discours représentant l’avis officiel de BP (communiqués de presse de BP). Nous avons analysé les discours publics d’Obama et de BP datant du 20 avril 2010 jusqu’au 19 septembre 2010. Nous avons considéré tout discours produit dans un contexte conflictuel travaillé par une crise comme un instrument porteur symboliquement des signes de pouvoir et mobilisant des rapports de force entre les acteurs impliqués. Nous partons de l’hypothèse suivante : les discours organisationnel et gouvernemental étudiés et produits dans un contexte de crise, sont forcément des discours conflictuels au sens de Windisch (1987). Et nous avons utilisé la grille d’analyse élaborée par Windisch (1987) pour mettre en exergue le fonctionnement interne d’un discours conflictuel envisagé comme un vecteur du pouvoir et de légitimation. Nous avons précédé l’analyse de discours, méthode principale dans notre étude, par une analyse de contenu qualitative. Le recours à l’analyse de contenu se justifie par notre souci de déterminer les divers thèmes développés dans le discours, d’examiner comment les acteurs imprègnent de sens le thème de la RSE et de poser le corpus dans sa réalité propre, en ayant recours au logiciel d’analyse de contenu qualitative HYPERRESEARCH. En outre, en mobilisant les présupposés théoriques et les outils méthodologiques issus de l’analyse de discours, nous avons ausculté le potentiel performatif légitimateur des discours construits et élaborés dans un contexte de communication conflictuelle. Pour ce faire, nous avons utilisé le logiciel d’analyse textuelle TROPES reconnu comme un outil d’analyse textuelle capable de générer des modèles représentatifs de la structure du corpus et de son organisation thématique. NOTIONS-CLÉS Discours conflictuel, stratégies discursives, RSE, légitimité, pouvoir, tandem État/firme. / Our study is intended to be an exploratory analysis based on a case study. Starting from a sample debate articulated around a public issue, namely the corporate social responsibility (CSR), we apprehend the discourse as an instrument of power deployed by actors in a conflict position. We take the ecological crisis caused by British Petroleum (BP) in the Gulf of Mexico since April 20, 2010 as a case study, and the reaction of the U.S. administration to intervene and reassure the public opinion alarmed by this crisis. In order to select our corpus, we have identified two target populations of discourse, in this case the speech given by the U.S. government (Obama's speech) and discourses representing the official opinion of BP (BP's press releases) dated April 20, 2010 until September 19, 2010. We considered any discourse occurring in a context of conflict symbolically as a power signs carrier and a mobilizing instrument of power relations between the involved actors. We start from the hypothesis stating that organizational and governmental discourses, studied and produced in a crisis context, are necessarily conflictual discourses within the meaning of Windisch (1987). And we used the analytical framework developed by Windisch (1987) to highlight the internal functioning of a confrontational speech seen as a vector of power and legitimacy. In our research, we preceded the discourse analysis, the main method in our study, by a qualitative content analysis. The use of content analysis aims to determine the various themes developed in the discourse, examine how actors define the CSR topic and put the corpus in its own reality, by using the HYPERRESEARCH qualitative content analysis software. In addition, by implementing the theoretical assumptions and methodological tools from discourse analysis, we auscultated the performative legitimating potential of discourses constructed and developed in a conflict communication context. We used the TROPES text analysis software recognized as a textual analysis tool able to generate representative models of the corpus structure and its thematic organization. KEY CONCEPTS Confrontational discourse, discursive strategies, CSR, legitimacy, power, tandem of government and enterprise.

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