Made available in DSpace on 2014-12-17T14:08:30Z (GMT). No. of bitstreams: 1 EdneyRVPG.pdf: 3193441 bytes, checksum: 9108a5643f51fcfe4a8b7479be215c58 (MD5) Previous issue date: 2008-08-18 / Currently a resource more and more used by the petroleum industry to increase the efficiency of steam flood mechanism is the addition of solvents. The process can be understood as a combination of a thermal method (steam injection) with a miscible method (solvent injection), promoting, thus, the reduction of interfacial tensions and oil viscosity. The use of solvent alone tends to be limited because of its high cost. When co-injected with steam, the vaporized solvent condenses in the cooler regions of the reservoir and mixes with the oil, creating a zone of low viscosity between the steam and the heavy oil. The mobility of the displaced fluid is then improved, resulting in an increase of oil recovery. To better understand this improved oil recovery method, a numerical study of the process was done contemplating the effects of some operational parameters (distance between wells, injection steam rate, kind of solvent and injected solvent volume)on the accumulated production of oil, recovery factor and oil-steam rate. Semisynthetic models were used in this study but reservoir data can be extrapolated for practical applications situations on Potiguar Basin. Simulations were performed in STARS (CMG, 2007.11). It was found that injected solvent volumes increased oil recovery and oil rates. Further the majority of the injected solvent was produced and can be recycled / Um recurso cada vez mais utilizado pela ind?stria petrol?fera para aumentar a efici?ncia do mecanismo de inje??o de vapor ? a adi??o de solventes. O processo pode ser compreendido como a combina??o de um m?todo t?rmico (inje??o de vapor) com um m?todo misc?vel (inje??o de solvente), promovendo, dessa forma, a redu??o das tens?es interfaciais e da viscosidade do ?leo. O uso do solvente sozinho tende a ser limitado, em fun??o do seu alto custo. Quando coinjetado com o vapor, o solvente vaporizado condensa nas regi?es menos quentes do reservat?rio e mistura-se ao ?leo, criando uma zona de baixa viscosidade entre o vapor e o ?leo pesado. A mobilidade do fluido deslocado ? ent?o melhorada, implicando num aumento do fator de recupera??o. Para melhor compreender esse mecanismo de recupera??o avan?ada, foi realizado um estudo num?rico, onde se verificou a sensibilidade de alguns par?metros operacionais (dist?ncia entre po?os, vaz?o de inje??o de vapor, tipo de solvente injetado e quantidade de solvente) sobre a produ??o acumulada de ?leo, o fator de recupera??o e a raz?o ?leo-vapor. Neste estudo, foram utilizados modelos semi-sint?ticos, por?m com dados de reservat?rio que podem ser extrapolados para situa??es de aplica??es pr?ticas na Bacia Potiguar. As simula??es foram realizadas no m?dulo STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) do programa da CMG (Computer Modelling Group), vers?o 2007.11. Os resultados mostraram que a presen?a do solvente nas quantidades analisadas melhorou os fatores de recupera??o e as vaz?es de ?leo. Al?m disso, a maior parte do solvente injetado foi produzido, podendo ser reciclado

Made available in DSpace on 2014-12-17T14:08:32Z (GMT). No. of bitstreams: 1 JoseTMAP.pdf: 3429155 bytes, checksum: 9d06d453f156a78546476b9e1a22c995 (MD5) Previous issue date: 2008-12-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Until the early 90s, the simulation of fluid flow in oil reservoir basically used the numerical technique of finite differences. Since then, there was a big development in simulation technology based on streamlines, so that nowadays it is being used in several cases and it can represent the physical mechanisms that influence the fluid flow, such as compressibility, capillarity and gravitational segregation. Streamline-based flow simulation is a tool that can help enough in waterflood project management, because it provides important information not available through traditional simulation of finite differences and shows, in a direct way, the influence between injector well and producer well. This work presents the application of a methodology published in literature for optimizing water injection projects in modeling of a Brazilian Potiguar Basin reservoir that has a large number of wells. This methodology considers changes of injection well rates over time, based on information available through streamline simulation. This methodology reduces injection rates in wells of lower efficiency and increases injection rates in more efficient wells. In the proposed model, the methodology was effective. The optimized alternatives presented higher oil recovery associated with a lower water injection volume. This shows better efficiency and, consequently, reduction in costs. Considering the wide use of the water injection in oil fields, the positive outcome of the modeling is important, because it shows a case study of increasing of oil recovery achieved simply through better distribution of water injection rates / At? o in?cio da d?cada de 90, a simula??o de fluxo em reservat?rio de petr?leo basicamente utilizava a t?cnica num?rica de diferen?as finitas. Desde ent?o, houve um grande desenvolvimento da tecnologia de simula??o com base em linhas de fluxo, de modo que hoje ela tem sido usada em v?rios casos e se encontra adequada para representar os diversos mecanismos f?sicos que influenciam o fluxo de fluidos no reservat?rio, tais como compressibilidade, capilaridade e segrega??o gravitacional. A simula??o baseada em linhas de fluxo ? uma ferramenta que pode ajudar bastante no gerenciamento de projetos de inje??o de ?gua, pois fornece informa??es importantes n?o disponibilizadas atrav?s da simula??o tradicional de diferen?as finitas e mostra, de forma direta, a influ?ncia entre po?o injetor e po?o produtor. Este trabalho apresenta a aplica??o de uma metodologia existente na literatura para otimizar projeto de inje??o de ?gua em um reservat?rio pertencente a um campo de petr?leo da Bacia Potiguar que possui elevado n?mero de po?os. Esta metodologia considera modifica??es das cotas de inje??o dos po?os ao longo do tempo, com base nas informa??es dispon?veis atrav?s da simula??o por linhas de fluxo. Esta metodologia reduz as vaz?es de inje??o dos po?os de menor efici?ncia e aumenta as vaz?es de inje??o dos po?os mais eficientes. No modelo proposto, a metodologia se mostrou eficaz. As alternativas de otimiza??o apresentaram uma maior recupera??o de ?leo associada a um menor volume de inje??o de ?gua. Isto demonstra uma melhor efici?ncia e, consequentemente, uma redu??o de custos. Considerando a ampla utiliza??o da inje??o de ?gua em campos de petr?leo, o resultado positivo da modelagem ? importante, porque apresenta um estudo de caso de aumento da recupera??o de petr?leo, alcan?ado simplesmente atrav?s de uma melhor distribui??o das vaz?es de inje??o de ?gua

Made available in DSpace on 2014-12-17T14:08:32Z (GMT). No. of bitstreams: 1 TommyAP_capa_ate_cap4.pdf: 809913 bytes, checksum: 0090aa039ef326f260cb40945133e6d1 (MD5) Previous issue date: 2009-04-27 / Petr?leo Brasileiro SA - PETROBRAS / The gas injection has become the most important IOR process in the United States. Furthermore, the year 2006 marks the first time the gas injection IOR production has surpassed that of steam injection. In Brazil, the installation of a petrochemical complex in the Northeast of Brazil (Bahia State) offers opportunities for the injection of gases in the fields located in the Rec?ncavo Basin. Field-scale gas injection applications have almost always been associated with design and operational difficulties. The mobility ratio, which controls the volumetric sweep, between the injected gas and displaced oil bank in gas processes, is typically unfavorable due to the relatively low viscosity of the injected gas. Furthermore, the difference between their densities results in severe gravity segregation of fluids in the reservoirs, consequently leading to poor control in the volumetric sweep. Nowadays, from the above applications of gas injection, the WAG process is most popular. However, in attempting to solve the mobility problems, the WAG process gives rise to other problems associated with increased water saturation in the reservoir including diminished gas injectivity and increased competition to the flow of oil. The low field performance of WAG floods with oil recoveries in the range of 5-10% is a clear indication of these problems. In order to find na effective alternative to WAG, the Gas Assisted Gravity Drainage (GAGD) was developed. This process is designed to take advantage of gravity force to allow vertical segregation between the injected CO2 and reservoir crude oil due to their density difference. This process consists of placing horizontal producers near the bottom of the pay zone and injecting g?s through existing vertical wells in field. Homogeneous models were used in this work which can be extrapolated to commercial application for fields located in the Northeast of Brazil. The simulations were performed in a CMG simulator, the STARS 2007.11, where some parameters and their interactions were analyzed. The results have shown that the CO2 injection in GAGD process increased significantly the rate and the final recovery of oil / A inje??o de g?s tem sido o m?todo de recupera??o mais utilizado nos Estados Unidos e o ano de 2006 marca a primeira vez em que a produ??o proveniente dos processos de inje??o de g?s superou os de inje??o de vapor. No Brasil, a instala??o do complexo petroqu?mico, no estado da Bahia, oferece oportunidades para inje??o de g?s na Bacia do Rec?ncavo. As aplica??es de inje??o de g?s em campo foram quase sempre associadas com dificuldades operacionais e de projetos. A raz?o de mobilidade, que controla a varredura volum?trica, entre o g?s injetado e o banco de ?leo deslocado, ? tipicamente desfavor?vel devido ? baixa viscosidade do g?s. Al?m de que a diferen?a entre as densidades conduz a segrega??o gravitacional severa dos fluidos no reservat?rio e consequentemente, levando a um pobre controle na varredura volum?trica. Atualmente, grande parte dos projetos de inje??o de g?s no mundo ? do tipo WAG. Entretanto, na tentativa de resolver os problemas de mobilidade, o processo WAG causa outros problemas como o aumento na satura??o de ?gua no reservat?rio, incluindo a diminui??o na injetividade do g?s e aumento da competi??o no fluxo do ?leo. O baixo desempenho na recupera??o de ?leo deste processo no campo, na ordem de 5 a 10%, ? uma clara indica??o destes problemas. A fim de encontrar uma alternativa eficaz para o WAG, o processo de drenagem gravitacional assistida por inje??o de g?s (GAGD) foi desenvolvido. O processo GAGD ? projetado para tomar vantagem da for?a gravitacional causando assim, a segrega??o vertical entre o CO2 injetado e a reserva de ?leo devido ? diferen?a de densidades. Este processo consiste na coloca??o de po?os produtores horizontais pr?ximos a parte inferior da zona de ?leo e inje??o de g?s atrav?s de po?os verticais existentes em campo. Modelos homog?neos foram utilizados neste trabalho os quais podem ser extrapolados para aplica??o comercial em campos localizados no nordeste brasileiro. As simula??es foram realizadas no simulador da CMG STARS 2007.11, sendo analisados alguns par?metros e suas intera??es. Os resultados mostraram que a inje??o de CO2 no processo GAGD aumentou significativamente a vaz?o e a recupera??o final de ?leo

Made available in DSpace on 2014-12-17T14:08:36Z (GMT). No. of bitstreams: 1 AmandaGO.pdf: 1269225 bytes, checksum: bb3d37e917eb9a6a37d5196f82512218 (MD5) Previous issue date: 2010-01-27 / The objective of reservoir engineering is to manage fields of oil production in order to maximize the production of hydrocarbons according to economic and physical restrictions. The deciding of a production strategy is a complex activity involving several variables in the process. Thus, a smart system, which assists in the optimization of the options for developing of the field, is very useful in day-to-day of reservoir engineers. This paper proposes the development of an intelligent system to aid decision making, regarding the optimization of strategies of production in oil fields. The intelligence of this system will be implemented through the use of the technique of reinforcement learning, which is presented as a powerful tool in problems of multi-stage decision. The proposed system will allow the specialist to obtain, in time, a great alternative (or near-optimal) for the development of an oil field known / O objetivo da engenharia de reservat?rios ? o de gerenciar campos de produ??o de petr?leo de forma a maximizar a produ??o dos hidrocarbonetos obedecendo a restri??es f?sicas e econ?micas existentes. A defini??o de estrat?gias de produ??o ? uma atividade complexa por envolver diversas vari?veis do processo. Deste modo, um sistema inteligente, que auxilie na otimiza??o das alternativas de desenvolvimento do campo, torna-se bastante ?til no dia-a-dia dos engenheiros de reservat?rios. Este trabalho prop?e o estudo preliminar de um sistema inteligente de aux?lio ? tomadas de decis?es, no que diz respeito ? otimiza??o de estrat?gias de produ??o em campos de petr?leo. A intelig?ncia desse sistema ser? implementada por meio do uso da t?cnica de aprendizado por refor?o, a qual se apresenta como uma poderosa ferramenta em problemas de decis?o multi-est?gios. O sistema estudado visa permitir que o especialista obtenha, em tempo h?bil, a alternativa ?tima (ou quase-?tima) para o desenvolvimento de um campo de petr?leo conhecido

Made available in DSpace on 2014-12-17T14:08:38Z (GMT). No. of bitstreams: 1 Janaina Medeiros Dantas Barbosa_DISSERT_01_35.pdf: 3284535 bytes, checksum: 7cd819680331f233db6c8299e7522b7b (MD5) Previous issue date: 2009-06-12 / Petr?leo Brasileiro SA - PETROBRAS / Continuous steam injection is one of heavy oil thermal recovery methods used in the Brazilian Northeast because of high occurrence of heavy oil reservoir. In this process, the oil into the reservoir is heated while reduces, substantially, its viscosity and improves the production. This work analyzed how the shaly sand layers influenced in the recovery. The studied models were synthetics, but the used reservoir data can be extrapolated to real situations of Potiguar Basin. The modeling was executed using the STARS - Steam Thermal and Advanced Process Reservoir Simulator - whose version was 2007.10. STARS is a tool of CMG Computer Modeling Group. The study was conducted in two stages, the first we analyzed the influence of reservoir parameters in the thermal process, so some of these were studied, including: horizontal permeability of the reservoir and the layer of shaly sand, ratio of horizontal permeability to vertical permeability, the influence of capillary pressure layer of shaly sand and as the location and dimensions of this heterogeneity can affect the productivity of oil. Among the parameters studied the horizontal permeability of the reservoir showed the most significant influence on the process followed by diversity. In the second stage three models were selected and studied some operational parameters such as injection rate, distance between wells, production time and completion intervals. Among the operating parameters studied the low rate and intermediate distances between wells showed the best recoveries / A inje??o cont?nua de vapor ? um dos m?todos t?rmicos de recupera??o de ?leos pesados utilizados no Nordeste Brasileiro, devido ? grande ocorr?ncia de reservat?rios contendo este tipo de ?leo. Este processo consiste em aquecer o ?leo existente no reservat?rio diminuindo substancialmente a sua viscosidade melhorando assim, a sua produ??o. Neste trabalho foi estudada qual a influ?ncia da presen?a de camadas de areia argilosas no reservat?rio para este tipo de recupera??o. Os modelos s?o sint?ticos, por?m com dados de reservat?rios que podem ser extrapolados para situa??es de aplica??es pr?ticas na Bacia Potiguar que apresenta reservat?rios com essa heterogeneidade. A modelagem foi implementada no simulador de recupera??o t?rmica STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) vers?o 2007.10 da CMG (Computer Modelling Group). O estudo foi realizado em duas etapas, na primeira foi analisada a influ?ncia dos par?metros de reservat?rio neste processo t?rmico, sendo assim, alguns desses foram estudados, dentre eles: permeabilidade horizontal do reservat?rio e da camada de areia argilosa, rela??o da permeabilidade horizontal com a permeabilidade vertical, influ?ncia da press?o capilar da camada de areia argilosa e como a localiza??o e as dimens?es dessa heterogeneidade podem afetar a produtividade de ?leo. Dentre os par?metros estudados a permeabilidade horizontal do reservat?rio foi o que apresentou maior influ?ncia significativa ao processo seguido da heterogeneidade. Na segunda etapa foram selecionados tr?s modelos e estudado alguns par?metros operacionais, tais como: vaz?o de inje??o, dist?ncia entre po?os, tempo de produ??o e intervalos de completa??o. Dentre os par?metros operacionais estudados as baixas vaz?es e as dist?ncias entre po?os intermedi?rias foram as que apresentaram as melhores recupera??es

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-16T22:25:59Z No. of bitstreams: 1 GilmarAlexandreGuedesJunior_DISSERT.pdf: 5929995 bytes, checksum: a36bb4fc00b8498bf0fbb8727e65d0ec (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-23T21:46:54Z (GMT) No. of bitstreams: 1 GilmarAlexandreGuedesJunior_DISSERT.pdf: 5929995 bytes, checksum: a36bb4fc00b8498bf0fbb8727e65d0ec (MD5) / Made available in DSpace on 2016-08-23T21:46:54Z (GMT). No. of bitstreams: 1 GilmarAlexandreGuedesJunior_DISSERT.pdf: 5929995 bytes, checksum: a36bb4fc00b8498bf0fbb8727e65d0ec (MD5) Previous issue date: 2016-04-29 / A prov?ncia pr?-sal ? composta por grandes acumula??es de ?leo leve, de excelente qualidade e com alto valor comercial, uma realidade que coloca o Brasil em uma posi??o estrat?gica frente ? grande demanda de energia mundial. Nessa prov?ncia encontram-se as maiores descobertas realizadas no mundo nos ?ltimos dez anos; as ?reas de Libra, de Franco e o Campo de Lula, todas com volumes superiores a 8 bilh?es de barris de ?leo recuper?veis. Para desenvolver e otimizar a produ??o desses campos, foi feito um estudo para escolha dos m?todos de recupera??o avan?ada, tendo como principais motiva??es a presen?a do di?xido de carbono (CO2) como contaminante e a decis?o estrat?gica de n?o o descartar, combinada ? alta RGO (raz?o g?s-?leo) do fluido do reservat?rio. O m?todo deveria tirar vantagem dos ?nicos recursos abundantes: a ?gua do mar e o g?s produzido. Dessa maneira, o processo de combinar esses recursos na inje??o alternada de ?gua e g?s (WAG) passou a ser visto como uma boa op??o. Nessa disserta??o, foi desenvolvido um modelo de reservat?rio com caracter?sticas do pr?-sal brasileiro, sendo aplicado o m?todo de recupera??o avan?ada de inje??o alternada de ?gua e g?s. O potencial de produ??o desse reservat?rio foi analisado por meio de par?metros como: fluido que inicia o processo de inje??o, posi??o das completa??es dos po?os injetores, bem como vaz?es de inje??o de ?gua e de g?s e o tempo de ciclo de cada fluido injetado. Os resultados mostraram um bom desempenho do m?todo WAG-CO2 misc?vel, com ganhos de at? 26% no FR com rela??o a recupera??o prim?ria, j? a aplica??o da inje??o de ?gua e de g?s, de maneira individual, n?o foi capaz de superar o patamar de 10% de ganho. O par?metro de maior influ?ncia nos resultados foi o tempo de ciclo, com maiores valores de FR obtidos com a utiliza??o dos menores tempos. / The pre-salt province is composed by large amounts of light oil and with good quality, a reality that puts Brazil in a strategic position facing the great demand for energy worldwide. In this province are the largest discoveries in the world in the last ten years; areas as Libra, Franco and Lula field, everyone containing volumes greater than 8 billion recoverable oil barrels. To develop and optimize the production of these fields, a study was done for choosing the improved oil recovery methods. The main motivations were the presence of carbon dioxide (CO2) as a contaminant and the strategic decision of do not discard it, combined with high GOR (gas-oil ratio) of the reservoir fluid. The method should take advantage of the unique abundant resources: seawater and produced gas. This way, the process of matching these resources in the water alterning gas injection (WAG) became a good option. In this master?s dissertation, it was developed a reservoir model with average characteristics of the Brazilian pre-salt, where was applied the improved oil recovery method of water alternating gas. The production of this reservoir was analyzed by parameters as: the first fluid injected in the injection process, position of the injection wells completion, injection water and gas rate and cycle time. The results showed a good performance of the method, with up to 26% of gains in the recovery factor regarding the primary recovery, since the application of water injection and gas, individually, was not able to overcome 10 % of gain. The most influential parameter found in the results was the cycle time, with higher recovery factor values obtained with the use of shorter times.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-27T00:31:10Z No. of bitstreams: 1 AntonioItaloAlvesDeOliveira_DISSERT.pdf: 4463689 bytes, checksum: 551e6cfc6b5b3ee103a6159082da29de (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-09-02T20:35:09Z (GMT) No. of bitstreams: 1 AntonioItaloAlvesDeOliveira_DISSERT.pdf: 4463689 bytes, checksum: 551e6cfc6b5b3ee103a6159082da29de (MD5) / Made available in DSpace on 2016-09-02T20:35:09Z (GMT). No. of bitstreams: 1 AntonioItaloAlvesDeOliveira_DISSERT.pdf: 4463689 bytes, checksum: 551e6cfc6b5b3ee103a6159082da29de (MD5) Previous issue date: 2016-04-19 / A descoberta do pr?-sal em 2006 trouxe novas expectativas para o futuro do setor petrol?fero no Brasil. Por?m, muitos desafios est?o relacionados ? atividade de explora??o e produ??o daquela regi?o, como por exemplo a perfura??o de uma extensa camada de sal, quest?es de log?stica e a alta concentra??o de CO2 (entre 8% e 12%). Esse g?s associado ao g?s natural n?o pode apenas ser lan?ado para atmosfera por quest?es ambientais e, portanto, a reinje??o desse g?s pode ser uma alternativa vi?vel. O CO2 causa inchamento do ?leo, reduzindo sua viscosidade e, portanto, facilita o fluxo de ?leo para o po?o produtor. Foi modelado um reservat?rio com caracter?sticas do pr?-sal no simulador comercial da CMG (Computer Modelling Group). Foram analisados par?metros como vaz?o de inje??o, dist?ncia vertical entre os po?os produtor e injetor, comprimento dos po?os e dist?ncia do po?o produtor ? base do reservat?rio e como esses par?metros influenciam no processo. O tempo total de projeto foi de 35 anos e as an?lise ocorreram para o primeiro ano de projeto, 2 anos 5, 15. 20 e 35 anos. O melhor caso conferiu um fator de recupera??o de 60% e em todos os anos, a vaz?o de inje??o foi o par?metro que mais influenciou no projeto. Em seguida procedeu-se uma an?lise econ?mica para dois cen?rios: comprando CO2 e transportando atrav?s de um carboduto e reinjetando o mesmo no po?o a partir da separa??o do g?s da corrente de g?s natural. A partir da viabilidade econ?mica dos dois projetos, foi analisado os impactos no VPL de oscicla??es dos componentes do fluxo de caixa . / The Discovery of Pr?-Sal (huge oil field located in a pre-salt layer undersea) in 2006 increased the persperctive of petroleum production to Brazil. Characterized as an light oil (28? - 30? API) comparing to the national average, many challenges were overcome to make the exploration economically viable. One of the problems found to produce oil from that region was the high percentage of carbon dioxide (between 8% and 12%), reaching 75% molar in some regions like J?piter field. The alternative found was to reinject the carbon dioxide from the separation of the natural g?s made on own production platform (an FPSO). The reinjection study was realized from the modeling of an light oil, with 8% of carbon dioxide, and an homogeneous oil reservoir, semi-synthetic, with similar characteristics to that region. It was implemented a Project with a time of 35 years and studied the following paramethers: Carbon dioxide flow rate, vertical distance between horizontal rigs used, distance from the rig to the base of the reservoir and the length of the producer rig to the injector rig. After choosing the best scenario, it was realized an analysis of the sensibility related to the injection flow rate reaching a fraction of recovered oil of 64%. In sequence, was realized an economic analysis from two cases: for the first one was admitted the purchase of carbon dioxide from an anthropogenic source and its transport to the platform made by a carboduct. The second case was considered the reinjection of produced gas by the rig from the process of membrane permeation with posterior reinjection. The first one obtained a maximum NPV (Net Present Value) of US$129.885.806,68 and the second one a maximum NPV of US$325.329.657,00. At last, was realized an uncertainty analysis towards the components values of the cash flow for both cases, verifying wich components is more sensitive to the NPV.

Made available in DSpace on 2014-12-17T14:01:57Z (GMT). No. of bitstreams: 1 AnaCatarinaLR.pdf: 1581949 bytes, checksum: d36f953346d69da5932504873625ff62 (MD5) Previous issue date: 2008-07-03 / ?The aims of this study were: i) assessing the trophic state of the Mendubim reservoir (semi-arid, Rio Grande do Norte, Brazil; 05? 38 99,0 S 36?55 98,0 W) based on chlorophyll-a, total phosphorus and nitrogen concentrations and water transparency; ii) relating the patterns of temporal variation of zooplankton and phytoplankton to the trophic state of the reservoir and iii) investigating the carrying capacity of the reservoir for cage fish farming. The samplingwas done monthly from July 2006 to July 2007 in three stations at the reservoir: next to the dam (barrage), in the central region and in the mouth of the main tributary. The abiotic and biotic variables analyzed were: Secchi depth, volatiles and fixed suspended solids, chlorophyll-a, total phosphorus and nitrogen, TN:TP ratio and mesozooplankton and phytoplankton composition and biomass. The results showed that the reservoir can be considered as mesotrophic with mean concentrations of total nitrogen, phosphorus and chlorophyll-a equal to 1711, 1 ?g.L-1, 30,8 ?g.L-1 and 5,62 ?g.L-1 respectively. The Cyanophyceae class was the most representative in terms of density, with the presence of potentially toxic species such as Microcystis aeruginosa, Planktothrix planctonica, Cylindrospermopsis raciborskii, Aphanizomenon sp. ,Aphanocapsa delicatissima and Pseudanabaena acicularis. Among the zooplankton, the genus Notodiaptomus presented the largest biomass values. Overall, our results show that the light limitation should explain the weak relationship between chlorophyll-a and total phosphorus and nitrogen concentrations. We concluded that the water of Mendubim reservoir is suitable for intensive fish cage aquaculture. Based on the carrying capacity calculations for this reservoir, we found that the maximum sustainable yield of tilapias in cages in the reservoir is 126 ton per year assuming a factor of food conversion of 1.5: 1.0 and a phosphorus content in the fish food of 1% / ?Os objetivos do presente estudo foram: i) avaliar o estado tr?fico do reservat?rio Mendubim (semi-?rido, Rio Grande do Norte, Brasil; 05? 38 99,0 S 36?55 98,0 W ) com base nas concentra??es de clorofila-a, f?sforo e nitrog?nio total, e na transpar?ncia da ?gua; ii) relacionar os padr?es de varia??o temporal da composi??o e biomassa do fitopl?ncton e zoopl?ncton ?s varia??es do estado tr?fico do reservat?rio e iii) investigar a capacidade de suporte do reservat?rio para o desenvolvimento de atividades de piscicultura em tanques-redes. Para tanto, foram realizadas amostragem mensais no per?odo de julho/2006 a julho/2007 em tr?s pontos de coleta, sendo um pr?ximo ? barragem, outro na regi?o central do reservat?rio e o terceiro na desembocadura do principal tribut?rio. As vari?veis bi?ticas e abi?ticas analisadas foram: profundidade e transpar?ncia da coluna d??gua, concentra??es de s?lidos fixos e vol?teis em suspens?o, clorofila-a, nitrog?nio e f?sforo total, raz?o NT:PT, composi??o e biovolume do fitopl?ncton, composi??o e biomassa do mesozoopl?ncton. Os resultados obtidos mostraram que o reservat?rio em estudo pode ser considerado mesotr?fico com concentra??es m?dias de nitrog?nio total, f?sforo total e clorofila-a igual a 1711,1?g l-1 , 30,8 ?g l-1 e 5,62 ?g l-1 respectivamente. A classe Cyanophyceae foi a de maior representatividade em termos quantitativos, com a presen?a de esp?cies potencialmente t?xicas, tais como Microcystis aeruginosa, Planktothrix planctonica, Cylindrospermopsis raciborskii, Aphanizomenon sp., Aphanocapsa delicatissima e Pseudanabaena acicularis. Quanto ? comunidade zooplanct?nica, o g?nero Notodiaptomus, foi o que apresentou maiores valores de biomassa. De um modo geral, os resultados encontrados mostram que a limita??o do crescimento algal por luz, ? uma poss?vel explica??o para as fracas rela??es entre as concentra??es de clorofila-a e de f?sforo e nitrog?nio total no ambiente. Com isso, conclu?mos que as ?guas do reservat?rio Mendubim se encontram apropriadas para a produ??o de pescado num regime intensivo de cultivo em tanques-rede. Com base nos c?lculos da capacidade de suporte do ambiente, verificamos que a produ??o m?xima sustent?vel de til?pias em tanques-rede no reservat?rio ? da ordem de 126 toneladas por ano assumindo um fator de convers?o alimentar de 1,5:1,0 e um conte?do de f?sforo na ra??o de (1,0%)

Made available in DSpace on 2014-12-17T14:01:58Z (GMT). No. of bitstreams: 1 ThiagoPNM.pdf: 364395 bytes, checksum: d196df37d1feef6ed3e5d5cd9f931834 (MD5) Previous issue date: 2009-02-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The eutrofization is a natural process of accumulation of nutrients in aquatic?s body that it has been accelerated for the human?s actives, mainly the related with the activities of camp, industrial and the inadequate disposition of the domestic sewage. The enrichment of the aquatic?s body with nutrients, mainly the nitrogen and the phosphorus, and the consequent proliferation of algae and Cyanobacteria can commit the quality of the water for the public provisioning, for the fish farming and for other ends. The problem becomes more critical when there is a shortage of water naturally as in the semi-arid area of the Brazilian northeast. Before that problem this work had as objective evaluates the trophic state of six reservoirs of the basin of River Serid? of Rio Grande of Norte and also estimate the capacity of load of match of the reservoir and risk probabilities based on the established limits by the resolution Conama 357/05. The results demonstrate that the six reservoirs are eutrofization, with concentration of total phosphorus and cloro a in the water upster to 50 e 12 μg l-1. The results show that space homogeneity exists in the state trophic of the reservoirs, but a significant variation interanual in function of the increase of the concentrations of nutrients and decrease of the transparency of the water with the reduction of the body of water accumulated in the reservoirs.The results of the simulation risk estocastic show that the reservoirs could receive annually from 72 to 216 Kg of P, assuming a risk of 10% of increasing in more than 30 μg l-1 the annual medium concentrations of total match in the water of these reservoirs. This load could be high in until 360 kg of P a year in case the managers assume a risk of 10% of increasing in more than 50 μg l-1 the annual medium concentrations of total phosphorus in the waters of these reservoirs / A eutrofiza??o ? um processo de ac?mulo de nutrientes em ambientes aqu?ticos que tem sido acelerado pelas atividades antr?picas, principalmente as relacionadas com as atividades agropastoris, industriais e a disposi??o inadequada dos efluentes dom?sticos. O enriquecimento do ambiente aqu?tico com nutrientes, principalmente o nitrog?nio e o f?sforo, e a conseq?ente prolifera??o de algas e cianobact?rias podem comprometer a qualidade da ?gua para o abastecimento p?blico, para a piscicultura e para outros fins. O problema se torna mais cr?tico quando h? naturalmente uma escassez de ?gua como na regi?o semi-?rida do nordeste brasileiro. Diante dessa problem?tica este trabalho teve como objetivo avaliar o estado tr?fico de seis reservat?rios da bacia do Rio Serid? no Rio Grande do Norte e tamb?m mensurar a capacidade de carga de f?sforo dos reservat?rios visando o seu enquadramento segundo a resolu??o CONAMA 357/05. Os resultados demonstram que os seis reservat?rios encontram-se eutrofizados, com concentra??es de f?sforo total e clorofila a na ?gua superiores a 50 e 12 ?g l-1 respectivamente. Os resultados mostram que existe uma homogeneidade espacial, mas uma significativa varia??o interanual no estado tr?fico dos reservat?rios em fun??o das varia??es do volume de ?gua acumulado nos reservat?rios. Os resultados da simula??o estoc?stica de risco mostram que os reservat?rios com maior capacidade de carga poderiam receber anualmente at? 216 Kg de P, assumindo um risco de 10% de aumentar em mais de 30 ?g l-1 as concentra??es m?dias anuais de f?sforo total na ?gua destes reservat?rios. Esta carga poderia ser elevada em at? 360 kg de P por ano caso os gestores assumam um risco de 10% de aumentar em mais de 50 ?g l-1 as concentra??es m?dias anuais de f?sforo total nas ?guas destes reservat?rios

Made available in DSpace on 2014-12-17T14:02:02Z (GMT). No. of bitstreams: 1 JuskaMSM.pdf: 940466 bytes, checksum: 95c63af4ea67b2fb9341e2034e0242a4 (MD5) Previous issue date: 2006-07-30 / The incidence of toxic cyanobacterial blooms is one of the important consequences of eutrophication in aquatic ecosystems. It is a very common phenomenon in reservoirs and shrimp ponds in the State of Rio Grande do Norte (RN), Brazil. Cyanobacterias produce toxins which can affect aquatic organisms and men trough the food chain. Aiming to contribute to the studies of cyanobacterias in RN, we propose: a) to evaluate the toxicity of isolated cyanobacterias in important fresh-water environments; and b) to verify the effects of both natural and cultured blooms occurred in reservoirs for human supply and in the cladoceran Ceriodaphnia silvestrii. This study was carried out using samples of natural blooms occurred between March and October of 2004 in Gargalheiras Dam (08? L e 39? W), in July of 2004 in Armando Ribeiro Gon?alves Dam (06o S e 37o W) and in commercial shrimp ponds (Litopenaeus vannamei) located in fresh-water environments. The samples were collected with plankton net (20?m.) for identification, isolation and obtaining of phytoplanktonic biomass for liophilization and later toxicity bioassays. The toxicity of cultured samples and natural blooms was investigated through bioassays in Swiss mice. Quantification of cyanobacteria in samples was conducted following the ?termol method, with 300mL samples fixed with lugol. The toxicity test with Ceriodaphnia silvestrii followed ABNT, 2001 recommendations, and were accomplished with natural hepatotoxic bloom s samples and cultured samples of both non-toxic and neurotoxic C. raciborskii. In this test, five newborns, aged between 6 and 24 hours, were exposed to different concentrations (0 a 800 mg.L-1) of crude cyanobacterial extracts during 24 and 48 hours. Three replicates were used per treatment. The pH, temperature and dissolved oxygen at the beginning and after 24 and 48hours from the test were measured. We estimated the CL50 through the Trimmed Spearman-Karber method. The blooms were constituted by Microcystis panniformis, M. aeruginosa, Anabaena circinalis, Cylindrospermopsis raciborskii and Planktothrix agardhii, producers of mycrocistin-LR confirmed with HPLC analysis. Samples of hepatotoxic blooms registered toxinogenic potential for C. silvestrii, with CL50-24h value of 47.48 mg.L-1 and CL5048h of 38.15 mg.L-1 for GARG samples in march/2005; CL50-24h of 113,13 mg.L-1 and CL5048h of 88,24 mg.L-1 for ARG July/2004; CL50-24h of 300.39 mg.L-1 and CL50-48h of 149.89 mg.L-1 for GARG October/2005. For cultured samples, values of CL50-24h and CL50-48h for C. raciborskii toxic strains were 228.05 and 120.28 mg.L-1, respectively. There was no mortality of C. silvestrii during the tests with non-toxic C. raciborskii strain. The toxicity test with C. silvestrii presented good sensitivity degree to cyanotoxins. The toxicity of natural hepatotoxic blooms samples (microcystins) and cultured neurotoxic saxitoxins producer samples analyzed in this study give us strong indications of that toxin s influence on the zooplanktonic community structure in tropical aquatic environments. Eleven cyanobacteria strains were isolated, representing 6 species: Anabaenopsis sp., Cylindrospermopsis raciborskii, Chroococcus sp., Microcystis panniformis, Geitlerinema unigranulatum e Planktothrix agardhii. None presented toxicity in Swiss mice. The strains were catalogued and deposited in the Laborat?rio de Ecologia e Toxicologia de Organismos Aqu?ticos (LETMA), in UFRN, and will be utilized in ecotoxicol?gical and ecophysiological studies, aiming to clarify the causes and control of cyanobacterial blooms in aquatic environments in RN. This state s reservoirs must receive broader attention from the authorities, considering the constant blooms occurring in waters used for human consumption / Incid?ncia de flora??es t?xicas de cianobact?rias ? uma das conseq??ncias da eutrofiza??o nos ecossistemas aqu?ticos, sendo comum a sua ocorr?ncia em reservat?rios e viveiros de cultivo de camar?o no Estado Rio Grande do Norte. Cianobact?rias podem produzir toxinas que podem afetar organismos aqu?ticos e o homem atrav?s da cadeia alimentar. Visando contribuir com o desenvolvimento de estudos ecotoxicol?gicos de cianobact?rias no RN, nos propomos avaliar a toxicidade de cianobact?rias isoladas de ambientes de ?guas doces e verificar o efeito de cultura e flora??es naturais ocorridas em reservat?rios para abastecimento humano, no crust?ceo clad?cero Ceriodaphnia silvestrii. O estudo foi conduzido com amostras de flora??es naturais ocorridas em mar?o e outubro de 2004 na Barragem Gargalheiras (08? L e 39? W), em julho de 2004 na Barragem Armando Ribeiro Gon?alves (06o S e 37o W) e em fazendas comerciais de cultivo de camar?o (Litopenaeus vannamei), localizadas em ambientes de ?gua doce do RN (6o 58 S e 38o 36 W). As amostras de flora??es foram coletadas com rede de pl?ncton (20?m) para identifica??o, isolamento e obten??o de biomassa fitoplanct?nica para liofiliza??o e posterior determina??o da toxicidade por bioensaios. A toxicidade das amostras de culturas e flora??es naturais foi investigada atrav?s de bioensaios em camundongos Swiss. A quantifica??o das cianobact?rias foi realizada pelo m?todo de ?termol, utlizando-se amostras (300mL) fixadas com lugol. O teste de toxicidade com Ceriodaphnia silvestrii seguiu as recomenda??es da ABNT (2001) e foram realizadas com amostras de flora??es naturais hepatot?xicas e culturas de C. raciborskii neurot?xica e n?o t?xica. No teste, cinco neonatos com idade entre 6 e 24 horas foram expostos a diferentes concentra??es (0 a 800 mg.L-1) de extrato bruto de cianobact?rias durante 24 e 48 horas. Tr?s replicatas por tratamentos foram usadas. Foram medidos o pH, a temperatura e o oxig?nio dissolvido no in?cio, com 24 e com 48 horas do teste. Atrav?s do m?todo Trimmed Spearman-Karber foi estimado a CL50. As flora??es eram mistas e compostas por Microcystis panniformis, M. aeruginosa, Anabaena circinalis, Cylindrospermopsis raciborskii e Planktothrix agardhii, produtoras de microcistina- LR, confirmada atrav?s de an?lise por HPLC. Amostras de flora??es hepatot?xicas registraram potencial toxinog?nico para o C. silvestrii, com valores de CL50-24h de 47.48 mg.L-1 e CL50-48h de 38.15 mg.L-1 para a amostra de GARG mar/05; CL50-24h de 113,13 mg.L-1 e CL50-48h de 88,24 mg.L-1 para ARG jul/04; CL50-24h de 300.39 mg.L-1 e CL50-48h de 149.89 mg.L-1 para GARG 10/05. Para as amostras de cultura valores de CL50-24h e CL50-48h para a cepa t?xica de C. raciborskii foram de 228.05 e 120.28 mg.L-1, respectivamente. N?o houve mortalidade dos C. silvestrii nos testes com a cepa de C. raciborskii n?o-t?xica. O teste de toxicidade com C. silvestrii apresentou um bom grau de sensibilidade ?s cianotoxinas. A toxicidade das amostras de flora??es naturais hepatot?xicas (microcistinas) e culturas neurot?xicas produtoras de saxitoxinas verificadas neste estudo fornece forte indicativos da influ?ncia dessas toxinas sobre a estrutura da comunidade zooplanct?nica em ambientes aqu?ticos tropicais. Foram isoladas 11 cepas de cianobact?rias de reservat?rios e viveiros do Estado, representadas por 6 esp?cies: Anabaenopsis sp., Cylindrospermopsis raciborskii, Chroococcus sp., Microcystis panniformis, Geitlerinema unigranulatum e Planktothrix agardhii. Nenhuma cepa apresentou toxicidade em camundongos Swiss. As cepas foram catalogadas e depositadas no Laborat?rio de Ecologia e Toxicologia de Organismos Aqu?ticos (LETMA) da UFRN e ser?o utilizadas em estudos ecotoxicol?gicos e ecofisiol?gicos visando esclarecer as causas e controle de flora??es de cianobact?rias nos ambientes aqu?ticos do Estado. Os reservat?rios do Rio Grande do Norte devem merecer maior aten??o perante os ?rg?os respons?veis, tendo em vista os constantes florescimentos t?xicos de cianobact?rias em ?guas utilizadas para consumo humano