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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.
111

A Systematic Approach to Offshore Fields Development Using an Integrated Workflow

Alqahtani, Mari H. 2010 August 1900 (has links)
I present a systematic method to primary develop existing black oil fields. This method uses integrated reservoir development workflow (IRDW) that relies on integrated asset model (IAM). Developing any existing field means providing a plan that generally serves the development goal(s) specified by management. However, serving the development goal(s) by itself does not guarantee an optimal development plan. Plans that do not rely on an IAM are less accurate. Some plans do not include economics in their evaluation. Such plans are technically accepted but usually impractical or unprofitable. Plans that only evaluate the field based on current, or short-term, conditions are potential candidates for bottlenecks, thus costly reevaluations. In addition, plans that do not consider all suitable options are misleading and have no room for optimization. Finally, some plans are based on “rules of thumb,” ease of operations, or operators’ preference, not on technical evaluation. These plans mostly lower long-term profitability and cause further production problems. To overcome these problems, project management must form a multidisciplinary team that uses the IRDW. The IRDW guides the team through its phases, stages, and steps to selecting the optimal development plan. The IAM consists of geological, reservoir, wellbore, facility, and economic models. The IRDW dictates building an IAM for the base (do nothing) case and for each development plan. The team must evaluate each scenario over the lifetime of the field, or over the timeframe the management specifies. Net present value (NPV) and Present value ratio (PVR) for all options are compared to the base case and against each other. The optimum development plan is the one that have the highest NPV and highest PVR. The results of the research showed that forming a multidisciplinary team and using a LDFC saves time and it guarantees selecting the optimal development plan if all applicable development options are considered.
112

Nutrients and chlorophyll dynamics in Fort Cobb Reservoir

Lakish, Benjamin. January 2007 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 31, 2008) Includes bibliographical references.
113

Estudo limnológico na represa Carlos Botelho (Itirapina/Brotas-SP): uma reavaliação comparativa do sistema Lobo-Broa / Limnological study at Carlos Botelho reservoir (Itirapina/Brotas - SP): a comparative reevaluation of the Lobo-Broa system

Daniel Ferguson Motheo 24 June 2005 (has links)
Os reservatórios, por serem corpos de água dinâmicos e pelos seus usos múltiplos, sofrem acelerado processo de eutrofização. Neste estudo avaliou-se a atual condição da represa do Lobo (municípios de Brotas e Itirapina, SP) em relação a algumas características físicas, químicas e biológicas em uma perspectiva temporal. As amostragens foram realizadas em duas épocas representativas das estações seca e chuvosa, compreendidas no período de setembro de 2000 e junho de 2001. Foram estabelecidos seis pontos de coleta, nos quais foram coletadas amostras de água para análises de nutrientes, clorofila, material em suspensão, zooplâncton e foram também realizadas medidas \"in situ\" de variáveis físicas e químicas, com o multisensor Horiba U10. Os resultados obtidos revelaram que ocorreram variações sazonais de moderada amplitude, caracterizando dois períodos: o seco com temperaturas menores, águas mais oxigenadas, menor condutividade elétrica e maiores concentrações de nutrientes. O zooplâncton da represa do Lobo foi numericamente dominado pelos rotíferos, seguidos pelos cladóceros e copépodos em proporções bem menores, similarmente ao reportado pelos estudos anteriores, indicando que em nível de grandes grupos não houve ainda uma mudança na estrutura desta comunidade. As variações na densidade dos principais grupos zooplanctônicos estão relacionadas às características físicas e químicas das diferentes porções da represa (com maiores densidades na porção superior, mais eutrófica) e à sazonalidade, com maior abundância de rotíferos no período chuvoso e maiores densidades de protozoários e microcrustáceos no inverno. Durante o período de estudo a condição trófica do reservatório foi mesotrófica, contudo com níveis de nutrientes e biomassa do fitoplâncton, indicada pela concentração de clorofila, superiores aos níveis reportados para a década de 1970. Concluiu-se portanto que a represa está sofrendo um processo de eutrofização. / Reservoirs, being dynamic bodies of water and for their several uses, undergo an accelerated process of eutrophication. The aim of this research is to analyze the actual condition of the Lobo reservoir (Itirapina and Brotas districts, SP) in relation to some physical, chemical and biological characteristics in a temporal perspective. Sampling was made in two representative periods of both dry and rainy seasons, during the period of September 2000 and June 2001. Six sampling stations where established for the analysis of nutrients, chlorophyll, suspended material, zooplankton, and also some \"in situ\" measurements utilizing a Horiba U10 multisensor where taken at these same locations for the observation of some chemical and physical variables. The results revealed the occurrence of seasonal variations of moderate magnitude, putting in evidence two periods: a dry one with low temperatures, more oxygenated water, lower electrical conductivity and lower nutrient concentrations in opposition with a rainy season, that was identified by higher temperatures, lower dissolved oxygen concentrations, higher electrical conductivity and higher concentrations of nutrients. The zooplankton of Lobo reservoir was numerically dominated by rotifers, followed by cladocerans and copepods in lower abundances, as similarly reported by previous studies, showing that in terms of the major groups there still was no shift in the community structure. Variations in the density of the main zooplankton groups were related to the physical and chemical characteristics of the different parts of this reservoir (with higher densities in the upper portion, that was more eutrophicated) and due to the seasonality, with higher abundance of rotifers in the rainy season and bigger densities of protozoans and microcrustaceans in the winter. Throughout the period of study the trophic condition of the reservoir was mesotrophic, although with levels of nutrients and phytoplankton biomass, indicated by the concentration of chlorophyll, higher than those reported during the 70\'s. It was concluded that the reservoir is undergoing a slow eutrophication process.
114

Geochemical drivers of Mn removal in drinking water reservoirs under hypolimnetic oxygenation

Ming, Cissy L. 08 June 2023 (has links)
This study addressed the geochemical drivers of Mn removal, including pH, alkalinity and the presence of mineral particles. We conducted laboratory experiments and field monitoring at two drinking water reservoirs in southwestern Virginia – Falling Creek Reservoir (FCR) and Carvins Cove Reservoir (CCR). In laboratory experiments in pH and alkalinity-adjusted nanopure water solutions, we observed substantial Mn removal within 14 days only under high pH conditions (pH≥10). In experiments with high pH and moderate to high alkalinity (> 80 mg/L CaCO3), near-total Mn removal occurred within 2 hours, at a rate of 0.25 mg/L-1 hr-1. Mn removal occurred alongside precipitation of microscopic (<5 μm diameter) and macroscopic (>100 μm diameter) particles. Elemental analysis of particles with energy-dispersive X-ray spectroscopy (EDS) supports their identification as Mn(IV) oxides (MnOx), which suggests Mn removal driven by oxidation. Elevated alkalinity in high pH solutions promotes Mn oxidation by maintaining high pH through buffering, which sustains conditions favorable for Mn oxidation. Our results also suggest sorption of Mn and mineral-catalyzed Mn oxidation by Mn oxides formed through oxidation by dissolved oxygen. In experiments using filtered and unfiltered water from the two reservoirs, we observed significant Mn removal in experiments with unfiltered water, suggesting that particles may remove Mn by catalyzing oxidation or nucleating Mn oxide precipitation. Mn removal occurred at 0.05 d-1 in unfiltered FCR water and 0.002 d-1 in unfiltered CCR water. We observed no Mn removal in filtered water from either reservoir. Scanning electron microscope (SEM) and EDS of visible particles from reservoir water experiments suggests that quartz and clay minerals present in the water column may nucleate or catalyze Mn oxide formation. Overall, this research shows that Mn removal under HOx operation is influenced by a variety of factors, including pH, alkalinity and suspended particles. / Master of Science / Elevated concentrations of manganese (Mn), a naturally occurring contaminant, can impair drinking water quality in several ways – by introducing poor taste and smell, staining pipes and appliances, and potentially harming the health of young children. Hypolimnetic oxygenation (HOx) is a novel water treatment method deployed in lakes and reservoirs to control water column contamination of metals and nutrients, including Mn. By pumping oxygen into lakes and reservoirs, HOx systems create conditions favorable for Mn removal from the water column. Previous work in two southwestern Virginia drinking water reservoirs documented differences between sites in how effectively HOx systems are able to remove Mn. These reservoirs have significant differences in their chemical profiles – most notably in pH and alkalinity, which suggests a role for background water chemistry in influencing removal rates in lakes and reservoirs with HOx systems. We used laboratory experiments to simulate the effects of pH and alkalinity on Mn removal rates in oxygenated lakes and reservoirs. We observed substantial Mn removal within 14 days under high pH conditions (pH 10-11) and negligible removal in solutions at or under pH 8. In experiments with pH 10-11 and alkalinity over 80 mg/L, near-total Mn removal occurred within 24 hours. During the 24 hour removal window, we observed yellow-brown discoloration of our experimental solutions within 12 hours, followed by formation of loosely aggregated brown to black particles. Microscopy and elemental analyses indicate that initial discoloration occurs due to formation of 1-2 μm wide manganese oxides with needle-like crystals. The visible aggregates are also manganese oxides. Based on mineral characterization and the time series of Mn removal observed in our experiments, we believe that initial formation of Mn oxides creates a positive feedback loop in solutions of pH 10-11 and alkalinity over 80 mg/L. Mn oxides promote further Mn oxide formation by facilitating conversion of Mn in solution into forms that easily settle from water. Observations of particulate formation and solution chemistry in filtered vs. filtered reservoir water from FCR and CCR supports a pivotal role for particles in facilitating Mn removal. Our research addresses the impacts of water chemistry Mn removal in drinking water, and improves understanding of Mn cycling in natural freshwaters.
115

A carbonate reservoir model for Petersilie field in Ness County, Kansas: effective waterflooding in the Mississippian System

McCaw, Alyson Siobhan January 1900 (has links)
Master of Science / Department of Geology / Matthew Totten / The Petersilie oil field in Ness County, Kansas produces out of the Mississippian System, a reservoir composed mainly of shallow water carbonates, at depths of around 4375 ft (1334 m). The lithology of the field ranges from limestone to dolomite, to interlaminated limestone-dolomite beds. Chert is commonly found throughout. Petersilie field lies to the west of the Central Kansas Uplift, and to the east of the Hugoton Embayment. The field saw much drilling activity in the 1960’s, when it reached a production peak of nearly 378,000 barrels of oil per year. Production declined swiftly after that until the late 1990’s, when waterflooding was successfully employed. In this study, a reservoir model was produced for the Mississippian as it occurs in Petersilie field using the Department of Energy’s EdBOAST reservoir modeling software, with the intent of providing a reference for future drilling activity in the Mississippian and determining reservoir characteristics that may have contributed to the effectiveness of waterflooding in this area. The reservoir model was checked by simulation with a companion reservoir simulator program, BOAST 98. Subsequent comparison of simulated and actual oil production curves demonstrates the reliability of well log and drill stem test data for the field and proves the reservoir model to be a good fit for the Mississippian in Petersilie. Production curve analysis of Petersilie indicates the field was an ideal candidate for waterflooding because it has a solution-gas drive mechanism. As the field approached depletion from primary recovery, oil saturations remained high. Petersilie also exhibits high porosity and good permeability. The BOAST software was found to be an effective and inexpensive means for understanding the Mississippian reservoir in central to south-central Kansas. It was determined that BOAST has potential for practical use by smaller independent oil companies targeting the Mississippian in Kansas.
116

The 1996 population dynamics of microcrustacean zooplankton at Prairie Creek Reservoir in Delaware County, Indiana

Cescon, Cinzia Tatiana January 1997 (has links)
This research was conducted to provide baseline data on the population dynamics of microcrustacean zooplankton at Prairie Creek Reservoir in Delaware County, Indiana from 24 January 1996 to 30 December 1996. This lake is a shallow lake (average depth <8m) used for recreational fishing and water supply for the local community. No published studies of zooplankton have previously been conducted at this location. I intended to test the hypothesis that Prairie Creek Reservoir has the same microcrustacean populations of shallow lakes in this region. The findings were compared to other studies in several North American lakes and reservoirs. Biotic and abiotic factors were considered as related to the population dynamics of zooplankton. Zooplankton serve as a critical forage base for many fish species, including several of economic importance. Increases and changes in species composition of zooplankton organisms associated with eutrophic conditions may also be an indication of deteriorating water quality (Gannon 1972). The data from this research suggest that Prairie Creek Reservoir has the typical zooplankton populations of a shallow, eutrophic North American lake. The presence of relatively high numbers of organisms generally associated with eutrophic environments, such as Bosmina longirostris, Leptodiaptomus siciloides, Acanthocyclops vernalis, and others supports this idea. The data from this study will be helpful to fisheries and environmental managers and will provide a baseline for future studies. / Department of Biology
117

Incorporação quantitativa de dados de sismica 4D no processo de ajuste de historico / Quantitative incorporation of seismic 4D in history matching process

Ida, Mauro 14 August 2018 (has links)
Orientadores: Denis Jose Schiozer, Celio Maschio / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica, Instituto de Geociencias / Made available in DSpace on 2018-08-14T07:27:37Z (GMT). No. of bitstreams: 1 Ida_Mauro_M.pdf: 14939670 bytes, checksum: 3bac33f4177c36ec35c53933f345273b (MD5) Previous issue date: 2009 / Resumo: Boas decisões no gerenciamento de um campo de petróleo em produção dependem fortemente da confiabilidade da previsão de produção que demanda um modelo de escoamento que reproduza com boa precisão o histórico de produção. Devido à complexidade do processo de ajuste de histórico de produção, vários modelos podem resultar em ajustes aceitáveis, porém ainda com incertezas na previsão de produção, principalmente pelo fato de existirem algumas heterogeneidades de grande impacto não observadas na fase de caracterização do modelo. Para reduzir as incertezas, surgiu a tecnologia de sísmica 4D que a partir de análises qualitativas permite identificar frentes de saturação de água, resultando em grandes avanços na caracterização do reservatório e, conseqüentemente, no ajuste de histórico. Apesar de muito útil, em alguns casos podem levar a interpretações equivocadas, sendo necessário um procedimento adicional para o uso da informação dessa tecnologia. O objetivo principal deste trabalho é propor uma metodologia que utiliza simultaneamente os dados de produção e quantitativamente a impedância acústica da sísmica 4D para identificar as heterogeneidades do reservatório visando melhorar a qualidade do ajuste de histórico. A metodologia proposta consiste de duas etapas principais: parametrização e otimização com algoritmo genético. A validação da metodologia proposta foi realizada num modelo bidimensional five-spot com duas falhas geológicas e um canal de alta permeabilidade e a aplicação foi realizada num modelo modificado do Campo de Namorado com as seguintes características: total de 44 poços, uma falha geológica e um canal de alta permeabilidade. Em todos os modelos, foram constatados ganhos de qualidade no ajuste de histórico proporcionado pela incorporação quantitativa da sísmica 4D. / Abstract: Good decision making related to oilfield management depends on reliability of production forecast which demands calibrated reservoir simulation models. Due to the complexity of the production history matching process, there are many models with reasonable match but, many times, with different forecasts, mainly due to important heterogeneities that are not observed during the reservoir characterization phase. In order to reduce this uncertainty, a new technology named 4D seismic became available which uses quantitative analysis to identify water saturation front resulting in huge advance in reservoir characterization and consequently in history matching. Although this technology is very useful, in some cases, it can result in mistaken interpretation and it needs additional work to use this technology. The main objective of this work is to propose a methodology to use production data and quantitatively acoustic impedance from 4D seismic to identify reservoir heterogeneities to increase the quality of the history matching. The methodology proposed is divided in two main steps: parametrization and optimization with genetic algorithm. The validation of methodology proposed was done in a simple synthetic model and the application was done in the Namorado Field, modified with one geological fault and one channel with high permeability. / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo
118

Distribution of petroleum products with respect to boating activity in a reservoir

Mastran, Trina Ann 22 August 2009 (has links)
Motorboat activity can adversely effect the water quality of a reservoir. The potential impacts of motorboat activity on the Occoquan Reservoir's water and sediments were evaluated. Thirty-one sites, both marina and nonmarina, along the reservoir were selected. Sediment and water samples were collected in 1990, during peak boating activity, and in October, during low boating activity. The objectives of this research were to determine the concentrations of polyaromatic hydrocarbons (PAHs) in water and sediment samples and to determine if their presence was related to boating activity. The presence of other non-PAH organics was also determined. Contours of total PAH concentrations, boxplots and ANOVA analyses between marina and nonmarina sites were generated from gathered data in order to meet these objectives. PAHs were present in the water during peak boating activity and not detected during low boating activity, while PAHS were detected in the sediments during both sampling periods. The aqueous and sediment PAH concentrations were at or below the method detection limits. The PAH ratios of unalkylated PAHs confirmed PAH contamination to be of a combustion source. Boating was shown to be a PAH source to the water column, during peak boating activity, throughout the entire Occoquan Reservoir. An ANOVA between marina and nonmarina sites for the aqueous total PAH concentrations did not show a significant difference in June. This implied that boating did not cause any localized impacts to the water column and that there was another PAH source. There was a significant difference for total PAH concentrations between the marina and nonmarina sites for the sediment samples in June, showing localized impacts at marina areas due to boating activity. PAH profiles showed urban runoff as another major contributor to the PAH concentration in the water and sediments. The urbanization of Hooes Run and the hydrology of the reservoir caused urban runoff to impact localized areas. Finally, atmospheric deposition was also a source of PAHs to the sediments throughout the entire reservoir. Non-PAH organics found in a few of the water and sediment samples were the pesticides atrazine and p,p'-DDD, alkyl phosphates, alcohols and C₈ to C₁₂ hydrocarbons. / Master of Science
119

Chemical Analysis of the Bottom Deposits of Artificial Lakes with Special Emphasis on Lake Dallas

Patrick, Paul V. 06 1900 (has links)
This study is for the purpose of determining the chemical content of typical artificial reservoir bottom deposits.
120

Operational Modifications for Transitioning from Single Purpose to Multi-Purpose Reservoirs

Mingda Lu (19164271) 17 July 2024 (has links)
<p dir="ltr">Reservoirs play a vital role in water resource management, serving essential functions such as flood mitigation, water supply, power generation, and environmental conservation. In the U.S., many of these structures were constructed in the 1900s, and were primarily designed as single purpose facilities for flood risk reduction. Facing increasing threats of water shortages and groundwater depletion, the transition of these reservoirs to multi-purpose operations has never been more imperative. Operational modifications and optimizations emerge as a promising solution, offering cost-effectiveness, swift implementation, and minimal ecological disruption.</p><p dir="ltr">This dissertation advances the theory and framework of modification and optimization of reservoir operations to facilitate their transition from single to multi-purpose use. This dissertation begins with targeted optimization of static operations and progressively advances to dynamic strategies across complex multi-reservoir-river systems. This dissertation sets three primary objectives: (1) To develop a comprehensive framework for assessing the conversion potential of single-purpose reservoirs and optimizing static operation strategies for enhanced multi-purpose functionality. (2) To devise dynamic control strategies that bolster reservoir performance during extreme events through the implementation of inflow-based pre-release operations. (3) To employ a Multi-Objective Simulation-Optimization (MOSO) framework that integrates large-scale datasets and advanced optimization algorithms, optimizing multi-purpose, multi-reservoir operations in complex systems and enhancing decision-making through Multi-Criteria Decision-Making (MCDM) methods.</p><p dir="ltr">In the first objective, a robust framework is developed to evaluate and facilitate the conversion of single-purpose reservoirs into multi-purpose systems. Leveraging historical data, the proposed framework establishes Maximum Safe Water Levels (MSWLs) to optimize flood control while enhancing water supply capabilities. The methodology incorporates numerical reservoir simulation models alongside historical inflow data analysis of 15 reservoirs operated by the U.S. Army Corps of Engineers, Louisville District, all originally designed exclusively for single-purpose flood control. The findings reveal opportunities for some reservoirs to significantly increase their water supply without compromising flood management efficiency.</p><p dir="ltr">The second objective delves into dynamic control strategies for reservoir operation, with a focus on pre-release mechanisms. This objective utilizes inflow-based forecasting models to assess the impacts of different pre-release timings on flood mitigation. This study focuses on 11 of the reservoirs identified in the first objective as having potential for transition to multi-purpose use, exploring dynamic operational adjustments necessary for enhanced performance. The results show that a 72-hour pre-release lead time markedly enhanced flood control effectiveness, whereas a 24-hour lead time provides a practical compromise, achieving substantial flood mitigation with minimal adverse impacts.</p><p dir="ltr">The third objective involves developing an advanced framework utilizing the Multi-Objective Simulation-Optimization (MOSO) model and extensive datasets to optimize pre-release operations in multi-purpose reservoirs. Implementing the Non-dominated Sorting Genetic Algorithm II (NSGA-II) and Multi-Criteria Decision-Making (MCDM) methods, the framework integrates reservoir simulation models and flow routing to refine operations based on projected flood forecasts. Applied to the Green River watershed in Kentucky, this method produces Pareto-optimal solutions, elucidating the trade-offs between flood control, water supply reliability, and downstream channel performance. The results underscore the framework’s potential to significantly refine operational strategies, bolstered by sensitivity analyses that explore the effects of varying storage levels and inflow conditions, thus fostering adaptive, data-driven management for sustainable water resource optimization.</p><p dir="ltr">This dissertation contributes to the field of water resource management by demonstrating and developing innovative strategies and frameworks for the transition of single purpose reservoirs to multi-purpose systems, modifying flood control and enhancing water supply capabilities. This dissertation provides practical solutions with available data, simulation models, and optimization tools, which enable effective decision-making and operational adjustments under varying conditions. Overall, this dissertation presents a foundation for more resilient, reliable, and adaptive water management practices for reservoirs, that can meet diverse demands in a changing environmental landscape.</p>

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