Fractures are the main flow channels in naturally fractured reservoirs. Therefore the fracture permeability is a critical parameter to production optimization and reservoir management. Fluid pressure reduction caused by production induces an increase in effective stress in naturally fractured reservoirs. The change of effective stress induces fracture deformation and changes fracture aperture and permeability, which in turn influences the production. Coupled interactions exist in the fractured reservoir: (i) fluid pressure change induces matrix deformation and stress change; (ii) matrix deformation induces fluid volume change and fluid pressure change; (iii) fracture deformation induces the change of pore pressure and stress in the whole field (the influence disappears at infinity); (iv) the change of pore pressure and stress at any point has an influence on the fracture and induces fracture deformation. To model accurately the influence of pressure reduction on the fracture permeability change in naturally fractured reservoirs, all of these coupled processes need to be considered. Therefore, in this dissertation a fully coupled approach is developed to model the influence of production on fracture aperture and permeability by combining a finite difference method to solve the fluid flow in fractures, a fully coupled displacement discontinuity method to build the global relation of fracture deformation, and the Barton-Bandis model of fracture deformation to build the local relation of fracture deformation. The fully coupled approach is applied to simulate the fracture permeability change in naturally fracture reservoir under isotropic in situ stress conditions and high anisotropic in situ stress conditions, respectively. Under isotropic stress conditions, the fracture aperture and permeability decrease with pressure reduction caused by production, and the magnitude of the decrease is dependent on the initial effective in situ stress. Under highly anisotropic stress, the fracture permeability can be enhanced by production because of shear dilation. The enhancement of fracture permeability will benefit to the production of oil and gas.

A naturally fractured reservoir (NFR) is a reservoir with a connected network of fractures created by natural processes such as diastrophism and volume shrinkage (Ordonez et al. 2001). There are two models to simulate this kind of reservoirs: the discrete fracture model and the dual porosity model. In the dual porosity model, the matrix blocks occupy the same physical space as the fracture network and are identical rectangular parallelepipeds with no direct communication between isotropic and homogeneous matrix blocks. However, each fracture and matrix property is defined separately in the discrete fracture model. Another feature of this thesis is tracer testing. In this process, a chemical or radioactive element is injected to the reservoirs, and then it can be traced using the devices, which are designed to detect the tracers. Tracer tests have several advantages such as determining residual oil saturation, identifying barriers or high permeability zones in reservoirs, and providing the information on flow patterns. Limited number of research studies has been done on performing tracer tests in naturally fractured reservoirs. Also because there is not enough information about the advantages and disadvantages of the discrete fracture and the dual porosity models, researchers and engineers lack the expertise to confidently select either the discrete fracture or the dual porosity models to simulate the different types of NFRs. In this thesis, we compared the oil and water productions, and tracer concentration curves in various reservoir conditions, using both the discrete fracture and the dual porosity models. We used the ECLIPSE, which is a commercial software package in the area of petroleum industry, to model a naturally fractured reservoir. We performed a simple waterflooding with two conservative tracers on the reservoirs. The results presented in each section include the graphs of the oil production rate, water production rate, and tracer concentration. In addition, we presented the oil saturation profiles of a cross-section, which includes the production and injection wells. The results illustrated that both the discrete fracture and the dual porosity models are in good agreement, except for a few special cases. Generally, the oil production using the dual porosity model is more than in the discrete fracture model. The major disadvantage of the dual porosity model is that the fluid distribution in the matrix blocks is changing homogenously during the waterflooding period. In other words, ECLIPSE shows a constant value of the oil and water saturations in each time step for the matrix blocks. However, the dual porosity model is 3 to 4 times faster than the discrete fracture model. In the discrete fracture model, the users have complete control in defining the reservoirs. For example, the fracture aperture, fracture spacing, and fracture porosities can be set by the user. The disadvantage of this model is that millions of grid blocks are needed to model a large reservoir with small fracture spacing. / text

Naturally fractured reservoirs (NFRs) hold a significant amount of the world's hydrocarbon reserves. Compared to conventional reservoirs, NFRs exhibit a higher degree of heterogeneity and complexity created by fractures. The importance of fractures in production of oil and gas is not limited to naturally fractured reservoirs. The economic exploitation of unconventional reservoirs, which is increasingly a major source of short- and long-term energy in the United States, hinges in part on effective stimulation of low-permeability rock through multi-stage hydraulic fracturing of horizontal wells. Accurate modeling and simulation of fractured media is still challenging owing to permeability anisotropies and contrasts. Non-physical abstractions inherent in conventional dual porosity and dual permeability models make these methods inadequate for solving different fluid-flow problems in fractured reservoirs. Also, recent approaches for discrete fracture modeling may require large computational times and hence the oil industry has not widely used such approaches, even though they give more accurate representations of fractured reservoirs than dual continuum models. We developed an embedded discrete fracture model (EDFM) for an in-house fully-implicit compositional reservoir simulator. EDFM borrows the dual-medium concept from conventional dual continuum models and also incorporates the effect of each fracture explicitly. In contrast to dual continuum models, fractures have arbitrary orientations and can be oblique or vertical, honoring the complexity and heterogeneity of a typical fractured reservoir. EDFM employs a structured grid to remediate challenges associated with unstructured gridding required for other discrete fracture models. Also, the EDFM approach can be easily incorporated in existing finite difference reservoir simulators. The accuracy of the EDFM approach was confirmed by comparing the results with analytical solutions and fine-grid, explicit-fracture simulations. Comparison of our results using the EDFM approach with fine-grid simulations showed that accurate results can be achieved using moderate grid refinements. This was further verified in a mesh sensitivity study that the EDFM approach with moderate grid refinement can obtain a converged solution. Hence, EDFM offers a computationally-efficient approach for simulating fluid flow in NFRs. Furthermore, several case studies presented in this study demonstrate the applicability, robustness, and efficiency of the EDFM approach for modeling fluid flow in fractured porous media. Another advantage of EDFM is its extensibility for various applications by incorporating different physics in the model. In order to examine the effect of pressure-dependent fracture properties on production, we incorporated the dynamic behavior of fractures into EDFM by employing empirical fracture deformation models. Our simulations showed that fracture deformation, caused by effective stress changes, substantially affects pressure depletion and hydrocarbon recovery. Based on the examples presented in this study, implementation of fracture geomechanical effects in EDFM did not degrade the computational performance of EDFM. Many unconventional reservoirs comprise well-developed natural fracture networks with multiple orientations and complex hydraulic fracture patterns suggested by microseismic data. We developed a coupled dual continuum and discrete fracture model to efficiently simulate production from these reservoirs. Large-scale hydraulic fractures were modeled explicitly using the EDFM approach and numerous small-scale natural fractures were modeled using a dual continuum approach. The transport parameters for dual continuum modeling of numerous natural fractures were derived by upscaling the EDFM equations. Comparison of the results using the coupled model with that of using the EDFM approach to represent all natural and hydraulic fractures explicitly showed that reasonably accurate results can be obtained at much lower computational cost by using the coupled approach with moderate grid refinements. / text

This thesis takes Discursive Psychology as its main theoretical influence. Drawing on the resources of Discursive Psychology and utilising analytic tools provided by Conversation Analysis, these principles are applied to the study of addiction, and specifically alcohol problems. The data explored are telephone calls to an alcohol helpline. Four analytic chapters are presented. The first focuses on the concept of loss of control over drinking, identifying features of how this concept is constructed in talk and suggests possible functions of control talk for both callers and Advice Workers. The second analytic chapter examines how Advice Workers respond to callers' professed impaired control over their drinking and I demonstrate that embedded in discursive sequences of problem formulation and advice giving are issues of agency, accountability and responsibility. The thesis moves on to explore the role of knowledge in calls to an alcohol helpline and the analysis reveals that both the expert status of the Advice Worker and the speciality of the topic are co-constructed between the speakers on the helpline. The final analytic chapter features just one telephone call and demonstrates the application of such an analysis for alcohol service providers. The thesis ends with a discussion of the main overall findings and the implications of the research for clinical practice. I close by arguing that initial agency contact is a very important site of study and recommend that this should be explored utilising naturally-occurring talk.

The aim of this study was to provide information about the effects of construction materials on thermal comfort in residential buildings using Ecotect 5.0. Three residential buildings, each of different construction in the province of Yozgat, Turkey were used as study material to this end. At the end of this study, the effects of materials on thermal comfort have been explained by graphical and statistical analysis. Pertinent literature reports that the thermal responses of occupants depend to some extent on the outdoor climate in naturally ventilated buildings with operable windows. Furthermore, an adaptation occurs in these buildings regarding the occupants&amp / #8217 / previous thermal experiences, the availability of control, and shifts in expectations. The study therefore focused on collecting data on both indoor and outdoor air temperature and humidity to show the comfort level in such buildings. By collecting data on 3 houses constructed of different materials the author aimed to show the effects of materials on thermal comfort. The analyses were further extended with computer simulations, which enabled restriction of the parameters on construction materials. The study has shown that in naturally ventilated residential buildings, construction materials affect both thermal comfort and thermal performance of the buildings. Buildings with traditional construction material showed a better performance in achieving the preferred thermal comfort while decreasing energy costs.

This thesis is aimed to calculate the effective permeability tensor and to simulate the fluid flow in naturally fractured reservoirs. This requires an understanding of the mechanisms of fluid flow in naturally fractured reservoirs and the detailed properties of individual fractures and matrix porous media. This study has been carried out to address the issues and difficulties faced by previous methods; to establish possible answers to minimise the difficulties; and hence, to improve the efficiency of reservoir simulation through the use of properties of individual fractures. The methodology used in this study combines several mathematical and numerical techniques like the boundary element method, periodic boundary conditions, and the control volume mixed finite element method. This study has contributed to knowledge in the calculation of the effective permeability and simulation of fluid flow in naturally fractured reservoirs through the development of two algorithms. The first algorithm calculates the effective permeability tensor by use of properties of arbitrary oriented fractures (location, size and orientation). It includes all multi-scaled fractures and considers the appropriate method of analysis for each type of fracture (short, medium and long). In this study a characterisation module which provides the detail information for individual fractures is incorporated. The effective permeability algorithm accounts for fluid flows in the matrix, between the matrix and the fracture and disconnected fractures on effective permeability. It also accounts for the properties of individual fractures in calculation of the effective permeability tensor. The second algorithm simulates flow of single-phase fluid in naturally fractured reservoirs by use of the effective permeability tensor. This algorithm takes full advantage of the control volume discretisation technique and the mixed finite element method in calculation of pressure and fluid flow velocity in each grid block. It accounts for the continuity of flux between the neighbouring blocks and has the advantage of calculation of fluid velocity and pressure, directly from a system of first order equations (Darcy???s law and conservation of mass???s law). The application of the effective permeability tensor in the second algorithm allows us the simulation of fluid flow in naturally fractured reservoirs with large number of multi-scale fractures. The fluid pressure and velocity distributions obtained from this study are important and can considered for further studies in hydraulic fracturing and production optimization of NFRs.

Orientador: Pedro Luís da Costa Aguiar Alves / Banca: Dagoberto Martins / Banca: Roberto Estêvão Bragion de Toledo / Banca: Maria Aparecida Pessoa da Cruz Centurion / Banca: Silvano Bianco / Resumo: Este trabalho teve como objetivo identificar os períodos de interferência das plantas daninhas no algodoeiro de fibra naturalmente colorida (BRS Safira e BRS Verde), e avaliar o efeito da competição das plantas daninhas na produtividade desta cultura. Dois experimentos foram instalados na área experimental da Embrapa Algodão em Missão Velha, CE, (7º42'07'' de latitude e 39º24'18'' de longitude, altitude de 360 m) na safra 2007/2008, utilizando-se o espaçamento de 1,00 x 0,20 m. Utilizou-se o delineamento experimental em blocos ao acaso, com quatro repetições, os tratamentos constaram de duas: modalidades de competição (convivência e controle de plantas daninhas) e períodos de interferência das plantas daninhas. Os períodos iniciais de controle ou de convivência após a emergência da cultura foram 0-20, 0-40, 0-60, 0-80 dias após a emergência (DAE) e 0-colheita (120 dias). Para determinação dos períodos de interferência, considerando-se perdas na produtividade de 2, 5 e 10%; foi realizada análise de regressão do modelo sigmoidal de Boltzmann, utilizando-se os dados de produtividade separadamente dentro de cada modalidade de competição. A comunidade infestante para ambas cultivares, foi composta por 21 espécies, destacando-se: Richardia grandiflora, Amaranthus deflexus, Eleusine indica, Merremia aegyptia, Eragrotis pilosa, Cenchrus echinatus e Waltheria indica. Observou-se para cultivar BRS Safira, que os períodos anteriores a interferência (PAI) foram, respectivamente, 8, 14 e 20 DAE, para perdas na produtividade de 2, 5 e 10%; e os períodos críticos de prevenção a interferências (PCPI), para esses mesmo níveis de perdas, foram respectivamente, 100, 82 e 60 dias. Para cultivar BRS Verde, os PAIs foram, respectivamente, 25, 31 e 35 DAE, para perdas de 2, 5 e 10%; e os PCPIs, para esses mesmo níveis de perdas, foram respectivamente ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to determine the late-season presence of weeds in reddish brown cotton and green cotton (cultivars BRS Safira and BRS Verde) and the critical times for removing weeds. And assess the effect of weeds competition in the crop productivity. Two experiments were carried out in the area of Embrapa in Missão Mission-CE, Brazil, the region Cariri, located at 7º42'07'' S latitude and 39º24'18'' WGr. longitude, altitude of 360 m, in the 2007/2008 season. The treatments consisted of two control groups: weed-free crop during the initial period after crop emergency, and crop kept with weeds during initial period after plant emergency. Both consisted, 0, 20, 40, 60, 80 e 120 days after crop emergency (DAE). Regression analysis was performed of the model of sigmoidal Boltzmann, using data from productivity separately within each type of competition, to identify the critical periods of competition considering 2, 5 and 10% reduction in yield. The community of weeds, for both cultivars, was composed by 21 predominant species, standing out among them: Richardia grandiflora, Amaranthus deflexus, Eleusine indica, Merremia aegyptia, Eragrotis pilosa, Cenchrus echinatus and Waltheria indica. For cultivar BRS Safira, considering 2, 5 and 10% reduction in yield fiber as acceptable, the period preceding the interference was, respectively, 8, 14 and 20 (DAE). And the critical periods of prevention to interferences, for those same levels of losses, they were respectively, 100, 82 and 60 (DAE). For cultivar BRS Verde, considering 2, 5 and 10% reduction in yield fiber as acceptable, the period preceding the interference was, respectively, 25, 31 and 35 (DAE). And the critical periods of prevention to interferences, for those same levels of losses, they were respectively, 67, 43 and 22 (DAE). The BRS Safira cultivar was more susceptible to interference of the weed community that BRS Verde. / Doutor

For processing the theme of dissertation were prepared two walks and one field trip. 1-he first walk is focused naturally and the second walk is focused geographically. The aim of dissertation is to provide to schoolchildren a contact with a direct surroundings of the school and a place of residence. Chosen activities lead to recognition of \tilevsko and his outskirt.

A pesquisa desvelou o circuito espacial de produção do algodão naturalmente colorido na Paraíba. Procuramos destacar o papel da pesquisa pública, através do sistema de ações da Embrapa Algodão, localizada em Campina Grande-PB na transformação das condições tecnológicas desse tipo de algodão e sua viabilização para exploração comercial; a organização espacial da produção; os atores envolvidos e as novas relações que se estabelecem com o sistema de produção do algodão naturalmente colorido orgânico. Nossa tese é de que a Embrapa Algodão foi central no processo de recuperação da cotonicultura brasileira, que enfrentou grave crise na década de 1980 e levou ao declínio dessa cultura até o início década de 1990. De modo geral o presente trabalho, inserido nos recentes debates da geografia, procurou destacar o papel da ciência, da pesquisa, da inovação na constituição de um circuito espacial de produção, tendo como estudo de caso a Embrapa e o Algodão Naturalmente Colorido. No contexto da crise nacional do algodão essa empresa foi responsável pela pesquisa, melhoramento e desenvolvimento de cultivares de algodão branco adaptado para as condições ambientais do bioma Cerrado e o algodão naturalmente colorido, uma planta silvestre nativa para as condições do Semiárido e viável para o processamento industrial. Na pesquisa constatou-se que a reorganização da produção algodoeira na Paraíba (colorido), a partir dos anos 2000, foi resultado da combinação de diferentes variáveis, dentre as quais destacam-se a pesquisa (Embrapa) e o marketing e propaganda (empresários), além de variáveis regionais/locais representadas pela agricultura familiar e produção orgânica. Tal reorganização apresenta atualmente duas regiões de produção distintas: região do Cerrado e a região Semiárido, regiões que se caracterizam por diferentes modos de produção concretos, no sentido proposto por Santos ([1996] 2008). Além do algodão naturalmente colorido atualmente ser desenvolvido em sistema de produção orgânica, nas outras fases de produção, os pequenos empresários que fazem uso do algodão colorido em suas produções tem buscado se adequar as exigências das normas estabelecidas pelos mercados consumidores, formado principalmente por turistas, pessoas preocupadas com a sustentabilidade ambiental e social, com destaque para os consumidores dos países europeus. A pesquisa demostrou ainda que a confiança que há em torno dos trabalhos de pesquisa da Embrapa Algodão extrapolam os limites das pesquisas agronômicas, a ponto da instituição ser utilizada no marketing comercial de empresas. / The research unveiled the space circuit of naturally coloured cotton production in Paraíba. We try to highlight the role of public research, through the actions of Embrapa Algodão system, located in Campina Grande (Paraíba) in the transformation of technological conditions aforementioned sort of cotton and their development for commercial exploitation; the spatial organization of production; the actors involved and the new relations established with the naturally coloured organic cotton production system. Our thesis is that the Embrapa Algodão was very important in the process of recovery of the Brazilian cotton industry, which suffer crisis in the 1980s and led to the decline of this farming until the early 1990s. Overall this paper, inserted in recent debates geography, sought to highlight the role of science, research, innovation in the creation of a spatial circuit production, taking as a case study the Embrapa Algodão and Naturally Coloured Cotton. In the context of national cotton crisis such company was responsible for research, improvement and development of white cotton cultivars tailored to the environmental conditions of the Cerrado biome and naturally coloured cotton, which is a native wild plant to the conditions of semi-arid and feasible for processing industrial. This research found out that the reorganization of cotton production in Paraíba (coloured), from the 2000s, was a result from the combination of different variables, among which stand out the research (Embrapa) and the marketing and advertising (business) as well as regional/local variables represented by family farming and organic production. Such reorganization currently has two distinct production areas: the Cerrado region and the semi-arid region, which are regions characterized by different specific modes of production, in the sense proposed by Santos ([1996] 2008). Besides naturally coloured cotton currently being developed in organic production system, at other stages of production, small business owners who uses coloured cotton in their productions have been trying to adapt yourselves to the requirements of the standards set by consumer markets, mainly consisting of tourists, people concerned about the environmental and social sustainability, especially for consumers in European countries. The survey also demonstrated that confidence that there is about research works of Embrapa Algodão transcend the limits of agronomic research, to the point of the institution to be used in commercial marketing companies.

Arsenic (As) and nitrate (NO3) are common contaminants in groundwater that are introduced through a variety of natural and anthropogenic sources. In this study we investigated the sources and distribution of As and NO3 in Goshen Valley, Utah, USA. Goshen Valley is a semi-arid alluvial basin that is impacted by geothermal waters, agriculture, urban development, and legacy mining. In this study we sampled surface water, springs, and wells to analyze concentrations of major ions, trace elements (As, B, Ba, Ca, Fe, K, Li, Mg, Mn, Mo, Pb, Si, Sr, Zn), and stable isotopes in water (δ18O and δD). A subset of samples were also analyzed for 87Sr/86Sr, δ34S, and tritium (3H). Major ion concentrations showed high spatial variability ranging from freshwater to brines, with the highest concentrations found in springs discharging from playa sediments. Likewise, the highest trace element concentrations, including As, were found in the playa-impacted springs. Elevated NO3 concentrations were found in springs and wells in agricultural areas of the valley. δ18O and δD values range from -0.90238 to -17.6 and -37.0891 to -134.5 respectively and represent that the valley contains old groundwater, evaporative surface water, and mixed water signatures in multiple wells. Tritium values range from 0.5 to 7.8 and further show the diversity of water in the valley by indicating old, young, and mixtures of old and young waters. Variations in 87Sr/86Sr were used to evaluate flowpaths of waters with elevated As. 87Sr/86Sr ratios suggest that the groundwater has interacted with a mixture of lithologic units including Tertiary volcanics, Paleozoic carbonates, and Quaternary alluvial/lacustrine fill. Correlations with As and playa affected springs indicate playa sediments as a major As source. The As found in wells has no apparent elemental correlations or spatial patterns and is likely due to the naturally occurring As in the valley alluvium and carbonate units. NO3 in the valley is concentrated in agricultural areas and is likely due to fertilizers, livestock, and alfalfa crops. Of all the potential contaminant sources, the data suggests that the major source of As is the saline playa soils and the major source of NO3 is agricultural activities in the valley.