Avaliação da adição de Nanosílica e silicato de sódio em pastas de cimento para poços de petróleo com baixo gradiente de fratura

The oil wells cementing is a critical step during the phase of well drilling, because problems during the operation of slurry pumping and an incomplete filling of the annular space between the metal casing and the formation can cause the slurry loss. Therefore, the slurry adopted in primary cementing an oil well must be properly dosed so that these problems are avoided during its pumping. When you drill a well in a weak rock formation requires even more careful, because should be a limit of hydrostatic pressure exerted during cementation, that does not occur rock collapse. With the objective of performing the cementing of a well whose formation is weak or unconsolidated are employed lighter slurries. Thus, this study used slurries with sodium silicate and nano silica in concentrations of 0,1; 0,4; 0,7 e 1,0 gpc, in which the slurries with nano silica showed the rheological parameters higher concentrations of up to 0.7 gpc and for concentration of 1.0 the slurry with sodium silicate obtained the highest values, remaining above the limits for application in fields, mainly wells with low fracture gradient, because a significant increase in viscosity may result in an increase in pressure pumping in operations of secondary cementations. Furthermore, there was no decrease in strength with increasing concentration of additive. Then, it is possible use of these additives to formulate Lighter slurry

Plásticos reforçados a base de tecidos híbridos: efeitos da anisotropia e geometria normativa na caracterização mecânica e da fratura

As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy

Novo método para estimativa do gradiente de fratura para poços de petróleo

The development of oil wells drilling requires additional cares mainly if the drilling is in offshore ultra deep water with low overburden pressure gradients which cause low fracture gradients and, consequently, difficult the well drilling by the reduction of the operational window. To minimize, in the well planning phases, the difficulties faced by the drilling in those sceneries, indirect models are used to estimate fracture gradient that foresees approximate values for leakoff tests. These models generate curves of geopressures that allow detailed analysis of the pressure behavior for the whole well. Most of these models are based on the Terzaghi equation, just differentiating in the determination of the values of rock tension coefficient. This work proposes an alternative method for prediction of fracture pressure gradient based on a geometric correlation that relates the pressure gradients proportionally for a given depth and extrapolates it for the whole well depth, meaning that theses parameters vary in a fixed proportion. The model is based on the application of analytical proportion segments corresponding to the differential pressure related to the rock tension. The study shows that the proposed analytical proportion segments reaches values of fracture gradient with good agreement with those available for leakoff tests in the field area. The obtained results were compared with twelve different indirect models for fracture pressure gradient prediction based on the compacting effect. For this, a software was developed using Matlab language. The comparison was also made varying the water depth from zero (onshore wellbores) to 1500 meters. The leakoff tests are also used to compare the different methods including the one proposed in this work. The presented work gives good results for error analysis compared to other methods and, due to its simplicity, justify its possible application

Efeitos da radiação uv, temperatura e vapor aquecido nos compósitos poliméricos: monitoramento, instabilidade estrutural e fratura

The application of composite materials and in particular the fiber-reinforced plastics (FRP) has gradually conquered space from the so called conventional materials. However, challenges have arisen when their application occurs in equipment and mechanical structures which will be exposed to harsh environmental conditions, especially when there is the influence of environmental degradation due to temperature, UV radiation and moisture in the mechanical performance of these structures, causing irreversible structural damage such as loss of dimensional stability, interfacial degradation, loss of mass, loss of structural properties and changes in the damage mechanism. In this context, the objective of this thesis is the development of a process for monitoring and modeling structural degradation, and the study of the physical and mechanical properties in FRP when in the presence of adverse environmental conditions (ageing). The mechanism of ageing is characterized by controlled environmental conditions of heated steam and ultraviolet radiation. For the research, it was necessary to develop three polymer composites. The first was a lamina of polyester resin reinforced with a short glass-E fiber mat (representing the layer exposed to ageing), and the other two were laminates, both of seven layers of reinforcement, one being made up only of short fibers of glass-E, and the other a hybrid type reinforced with fibers of glass-E/ fibers of curaua. It should be noted that the two laminates have the lamina of short glass-E fibers as a layer of the ageing process incidence. The specimens were removed from the composites mentioned and submitted to environmental ageing accelerated by an ageing chamber. To study the monitoring and modeling of degradation, the ageing cycles to which the lamina was exposed were: alternating cycles of UV radiation and heated steam, a cycle only of UV radiation and a cycle only of heated steam, for a period defined by norm. The laminates have already undergone only the alternating cycle of UV and heated steam. At the end of the exposure period the specimens were subjected to a structural stability assessment by means of the developed measurement of thickness variation technique (MTVT) and the measurement of mass variation technique (MMVT). Then they were subjected to the mechanical tests of uniaxial tension for the lamina and all the laminates, besides the bending test on three points for the laminates. This study was followed by characterization of the fracture and the surface degradation. Finally, a model was developed for the composites called Ageing Zone Diagram (AZD) for monitoring and predicting the tensile strength after the ageing processes. From the results it was observed that the process of degradation occurs Abstract Raimundo Nonato Barbosa Felipe xiv differently for each composite studied, although all were affected in certain way and that the most aggressive ageing process was that of UV radiation, and that the hybrid laminated fibers of glass-E/curaua composite was most affected in its mechanical properties

Metodologia de análise e diagnóstico de fratura em um componente automotivo sujeito a cargas cíclicas alternadas

The competitiveness of the trade generated by the higher availability of products with lower quality and cost promoted a new reality of industrial production with small clearances. Track deviations at the production are not discarded, uncertainties can statistically occur. The world consumer and the Brazilian one are supported by the consumer protection code, in lawsuits against the products poor quality. An automobile is composed of various systems and thousands of constituent parts, increasing the likelihood of failure. The dynamic and security systems are critical in relation to the consequences of possible failures. The investigation of the failure gives us the possibility of learning and contributing to various improvements. Our main purpose in this work is to develop a systematic, specific methodology by investigating the root cause of the flaw occurred on an axle end of the front suspension of an automobile, and to perform comparative data analyses between the fractured part and the project information. Our research was based on a flaw generated in an automotive suspension system involved in a mechanical judicial cause, resulting in property and personal damages. In the investigations concerning the analysis of mechanical flaws, knowledge on materials engineering plays a crucial role in the process, since it enables applying techniques for characterizing materials, relating the technical attributes required from a respective part with its structure of manufacturing material, thus providing a greater scientific contribution to the work. The specific methodology developed follows its own flowchart. In the early phase, the data in the records and information on the involved ones were collected. The following laboratory analyses were performed: macrography of the fracture, micrography with SEM (Scanning Electron Microscope) of the initial and final fracture, phase analysis with optical microscopy, Brinell hardness and Vickers microhardness analyses, quantitative and qualitative chemical analysis, by using X-ray fluorescence and optical spectroscopy for carbon analysis, qualitative study on the state of tension was done. Field data were also collected. In the analyses data of the values resulting from the fractured stock parts and the design values were compared. After the investigation, one concluded that: the developed methodology systematized the investigation and enabled crossing data, thus minimizing diagnostic error probability, the morphology of the fracture indicates failure by the fatigue mechanism in a geometrically propitious location, a tension hub, the part was subjected to low tensions by the sectional area of the final fracture, the manufacturing material of the fractured part has low ductility, the component fractured in an earlier moment than the one recommended by the manufacturer, the percentages of C, Si, Mn and Cr of the fractured part present values which differ from the design ones, the hardness value of the superior limit of the fractured part is higher than that of the design, and there is no manufacturing uniformity between stock and fractured part. The work will contribute to optimizing the guidance of the actions in a mechanical engineering judicial expertise

Desenvolvimento de sistemas de pastas leves para aplicação em cimentação de poços petrolíferos com baixo gradiente de fratura

All around the world, naturally occurring hydrocarbon deposits, consisting of oil and gas contained within rocks called reservoir rocks , generally sandstone or carbonate exists. These deposits are in varying conditions of pressure and depth from a few hundred to several thousand meters. In general, shallow reservoirs have greater tendency to fracture, since they have low fracture gradient, ie fractures are formed even with relatively low hydrostatic columns of fluid. These low fracture gradient areas are particularly common in onshore areas, like the Rio Grande do Norte basin. During a well drilling, one of the most favorable phases for the occurrence of fractures is during cementing, since the cement slurry used can have greater densities than the maximum allowed by the rock structure. Furthermore, in areas which are already naturally fractured, the use of regular cement slurries causes fluid loss into the formation, which may give rise to failures cementations and formation damages. Commercially, there are alternatives to the development of lightweight cement slurries, but these fail either because of their enormous cost, or because the cement properties were not good enough for most general applications, being restricted to each transaction for which the cement paste was made, or both reasons. In this work a statistical design was made to determine the influence of three variables, defined as the calcium chloride concentration, vermiculite concentration and nanosilica concentration in the various properties of the cement. The use of vermiculite, a low density ore present in large amounts in northeastern Brazil, as extensor for cementing slurries, enabled the production of stable cements, with high water/cement ratio, excellent rheological properties and low densities, which were set at 12.5 lb / gal, despite the fact that lower densities could be achieved. It is also seen that the calcium chloride is very useful as gelling and thickening agent, and their use in combination with nanosilica has a great effect on gel strength of the cement. Hydrothermal Stability studies showed that the pastes were stable in these conditions, and mechanical resistance tests showed values of the order of up to 10 MPa

Segregação socioespacial e turismo: estudo da representação fílmica criada pelos turistas e residentes sobre Natal Rio Grande do Norte

This study emerges and develops, from a note by Italo Calvino, who in his novel Invisible Cities advised to avoid saying "that sometimes different cities follow on the same site and with the same name, born and die without knowing, without communication among itself ". The research with a transdisciplinary work ( using elements of sociology, anthropology, geography and communication) made a reflection about segregation and tourism: poverty-richness, center-periphery, tradition- spectaclezation , the visitor-visited maping the touristic circuit and discussing about the phenomenon on the real city and touristic place: Natal and the "Sun City" - Rio Grande do Norte, studying videos produced by residents (documentary) and tourists ( posted on the Internet). Doing a comparative analysis between the realities of these two subjects (resident and tourist), the research found few similarities, many differences on the urban experience, with the existence of two distinct realities (tourist region X the periphery region). Based on theory of phenomenology, social representation, and using content analysis of film, it was noted that promotes to the visitor a trip segmented and disintegrated to daily life, culture and contact with the resident. Resident that, in largely part, lives in a unattended area, with no prospect of life (represented by Novo Horizonte Community). The confinement and segregation occurs even in his moments of leisure and cultural expressions (represented by Redinha‟s Beach), because the private an public leisure areas of tourism indirectly prevent access by people who can not contribute to the consumption on this places. This papper concluded that the tourism in Natal is an activity-phenomenon that directs and focuses on public investments for infrastructure tourist region (Ponta Negra Beach), in detriment of the poorest and periphery areas of the city

Feira livre de Macaíba/RN : um estudo das modificações na dinâmica socioespacial (1960/2006)

The objective of the current piece of research is to reflect upon the diverse changes that have occurred in the social and spatial dynamics of the Macaíba fair in the period between 1960 and 2006. During the second half of the 19th century, Macaíba had in the commerce one of this principle economic base a contribution for which the city became one of the main commercial warehouses of the East coast of the Rio Grande do Norte region. This helped lead to the growth of Macaíba s fair, which proved to be one of the most important existing in the state until the 1970 s. In the last two decades of the 20th century, certain elements represented challenges to the fair at Macaíba. These challenges stimulated substantial changes in the fair s dynamics which include the growth and expansion of the commercial and service sector, primarily though supermarkets; consolidation among the commercial and distribution networks, represented by the Central Office of Supply of the Rio Grande do Norte S/A (Ceasa/RN), by the wholesale and refrigeration companies; and the modernization of transportation methods, which permitted an expanded reach for these networks. Even with all these changes, the fair continues to be one of the strongest aspects of the city being the center of resistance against the surge of new forms of commerce and consumption in the city (notable the supermarkets) and the diffusion of other aspects of globalization. The fair has economic importance, as it offers a popular marketplace for the commercialization of very different products and a means for supplying goods to the residents of the city and the rural communities of Macaíba and the surrounding municipalities; and socio-cultural importance in that the fair is a place where popular tradition is expressed, a place where a great number of parallel activities occur, a place for meeting again and again, of conversations, of manifestations of culture and art, and of socialization in all of its dimensions

Distribuição socioespacial dos fatores dinâmicos da população na Região Metropolitana de Natal

The Metropolitan Region of Natal, like other metropolitan regions in Brazil, was marked by intense and rapid urbanization of the country occurred only in the second half of the twentieth century, coinciding with the process of consolidation of the industry in the country, resulting in serious urban social problems, such as the increase in slums, lack of infrastructure and this increase in violence in urban centers. When enters the reality of the metropolitan region, assessing the impacts of restructuring productive in the context of globalization, analyzing how the socio-economic factors influencing the dynamic of the population, whose configuration was shown to be contradictory according to social class busy. Accordingly, we studied the demographic configuration of the Metropolitan Region of Natal, analyzing their spatial distribution and their socio-demographic differences in light of building a type socio-space, which cuts the metropolitan space in homogeneous areas

A televisão e a (re)construção do imaginário : as telenovelas e sua ifluência socioespacial em Caicó-RN

Under the perspective of the Cultural Geografhy, this dissetation thoretically discusses about the socio-spatial interference that the Rede Globo's soapoperas have in the construction of the collective imagination of the people who lines in the city of Caicó - RN. Here the social and spatial impacts produced by Rede Globo's main fiction program, the soapoperas, on the collective imagination of the inhabitants of Caicó are the main interest. The main argument here is that this TV program has an anormons influence on the evereday life of the people who live in Caicó and this influence ends up modifying their social, spatial and cultural pratices. This influence has been also working as the main force producing a real spatial impact. In this sense "new spaces of dialogue" are constructed through the influence of television. The main understandig is then that the soapoperas, at least within the context of Caicó, are a great force constructing social and spatial collective imagination of this city's inhabitants.

Avaliação da adição de Nanosílica e silicato de sódio em pastas de cimento para poços de petróleo com baixo gradiente de fratura

The oil wells cementing is a critical step during the phase of well drilling, because problems during the operation of slurry pumping and an incomplete filling of the annular space between the metal casing and the formation can cause the slurry loss. Therefore, the slurry adopted in primary cementing an oil well must be properly dosed so that these problems are avoided during its pumping. When you drill a well in a weak rock formation requires even more careful, because should be a limit of hydrostatic pressure exerted during cementation, that does not occur rock collapse. With the objective of performing the cementing of a well whose formation is weak or unconsolidated are employed lighter slurries. Thus, this study used slurries with sodium silicate and nano silica in concentrations of 0,1; 0,4; 0,7 e 1,0 gpc, in which the slurries with nano silica showed the rheological parameters higher concentrations of up to 0.7 gpc and for concentration of 1.0 the slurry with sodium silicate obtained the highest values, remaining above the limits for application in fields, mainly wells with low fracture gradient, because a significant increase in viscosity may result in an increase in pressure pumping in operations of secondary cementations. Furthermore, there was no decrease in strength with increasing concentration of additive. Then, it is possible use of these additives to formulate Lighter slurry

Plásticos reforçados a base de tecidos híbridos: efeitos da anisotropia e geometria normativa na caracterização mecânica e da fratura

As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy

Novo método para estimativa do gradiente de fratura para poços de petróleo

The development of oil wells drilling requires additional cares mainly if the drilling is in offshore ultra deep water with low overburden pressure gradients which cause low fracture gradients and, consequently, difficult the well drilling by the reduction of the operational window. To minimize, in the well planning phases, the difficulties faced by the drilling in those sceneries, indirect models are used to estimate fracture gradient that foresees approximate values for leakoff tests. These models generate curves of geopressures that allow detailed analysis of the pressure behavior for the whole well. Most of these models are based on the Terzaghi equation, just differentiating in the determination of the values of rock tension coefficient. This work proposes an alternative method for prediction of fracture pressure gradient based on a geometric correlation that relates the pressure gradients proportionally for a given depth and extrapolates it for the whole well depth, meaning that theses parameters vary in a fixed proportion. The model is based on the application of analytical proportion segments corresponding to the differential pressure related to the rock tension. The study shows that the proposed analytical proportion segments reaches values of fracture gradient with good agreement with those available for leakoff tests in the field area. The obtained results were compared with twelve different indirect models for fracture pressure gradient prediction based on the compacting effect. For this, a software was developed using Matlab language. The comparison was also made varying the water depth from zero (onshore wellbores) to 1500 meters. The leakoff tests are also used to compare the different methods including the one proposed in this work. The presented work gives good results for error analysis compared to other methods and, due to its simplicity, justify its possible application

O Litoral e a metrópole dinâmica imobiliária, turismo e expansão urbana na região metropolitana de Natal-RN

The metropolitan regions of Northeast Brazil are being gradually included in a scenario of international investments, which are motivated by the restructuring of both touristic and real-estate sectors. The new capital, real-estate developers and space configurations that result from this process indicate the need for the creation and implementation of public tools which should, at least, allow the mitigation of the urban impacts and environmental losses resulting from this situation. The effects on landscape and on the socio-spatial configuration result from the intensification caused by the dynamism of the "real estate-tourism" sector. There is a regional integration as an expression of the urban expansion of the metropolitan area of Natal. This study investigates the uniqueness of the restructuring and territorial integration of coastal areas and the strategies of the circuit of capital accumulation formed by linking the real estate to tourism. It is intended to increase the understanding about the strategies of tourism, real estate and public policy agents involved in this territorial reconfiguration and in the fund-raising needed for the investments, to understand the existing social and environmental effects and their future trends and also to understand the forms of spatial production as results from the practices of approaching the land transformation and the tourism valorization of the landscape, in a synchronous manner, first in the Northeast region and, as a focal study, in the Metropolitan Area of Natal. Likewise, it is intended to apprehend the current processes of metropolization of the eastern coast of Rio Grande do Norte, in addition to indicate its physical-territorial transformation and the types of projects/developments promoted by the market in the recent period. Based upon analysis undertaken for the Metropolitan Region of Natal RN, this piece of work presents some considerations on possible legal instruments that can be adjusted to the municipalities which are experiencing the impact of this peculiar and recent phenomenon in the region, caused by the arrival of the real estate-touristic capital. It is also intended to point out basic proposals to the forms of public intervention, in a speculative way, starting from a Metropolitan Planning project within a medium and long term

Uma viagem insólita: de um território pesqueiro a um paraíso turístico

O presente trabalho intitulado Uma viagem insólita: de um território pesqueiro a um paraíso turístico tem como objetivo buscar compreender e interpretar as mudanças socioespaciais que ocorreram na Praia da Pipa/RN, decorrentes da expansão da atividade turística e seus reflexos no território, no período compreendido entre os anos de 1970 e os dias atuais, recorrendo-se a fontes bibliográficas, entrevistas e observações in loco, além de levantamento de dados secundários, cartográficos e fotográficos. Reporta à nova territorialidade que emergiu com a expansão da atividade turística para o litoral norte-rio-grandense, atraída pela praia e pelo sol, que fez convergir para essa área, produtores e consumidores não apenas locais, mas também regionais, nacionais e internacionais. Do ponto de vista social, a população nativa vem sendo expropriada de seus espaços, da sua cultura, das suas tradições e, até mesmo, do mercado de trabalho, o que vem provocando um processo de desterritorialização e o surgimento de novas territorialidades marcadas pela atividade turística. A expansão da atividade turística em Pipa/RN, a partir de 1970, tem provocado um processo de construção de um novo território o território turístico que se reflete dialeticamente através do surgimento de um novo cenário socioespacial constituído de formas e imagens expressas materialmente no lugar