[pt] Esta dissertação tem como objetivo a utilização de modelos de regressão linear para a taxa de penetração de banda larga, baseados nas variáveis desemprego, PIB per capita, grau de competividade do mercado e diversidade tecnológica, utilizando uma análise dos modelos em diferentes países, com ênfase no Brasil, onde, nos últimos anos, tem sido analisadas diferentes alternativas para alcançar os objetivos do Plano Nacional de Banda Larga. A aplicação da metodologia apresentará a relação destas variáveis para os países com índices de adoção de banda larga ainda baixos, onde o Brasil está incluído, mas também apresenta a análise para países mais maduros neste índice. Estas análises poderão auxiliar na tomada de decisão das políticas públicas adequadas para o Brasil, buscando a aproximação dos países desenvolvidos neste setor. / [en] This thesis has as objective the developing of a model to estimate the broadband density penetration based on the unemployment rate, Gross Domestic Product per capita, market share and technological diversity. In addition of a global analysis, the thesis is focused in the Brazilian scenario, which is in a process of decision in which government policies to achieve the results expected by the National Broadband Plan. The methodoly will present the relation between these variables for the countries with lower broadband indexes, where Brazil is included, and the analysis for the countries with better indexes. These analyses can help Brazilian government in which policies should help Brazil to achieve results closer than the more mature countries in this sector.

A drilling operation leads to thermal disturbances in the near-wellbore stress, which is an important cause of many undesired incidents in well drilling. A major cause of this thermal disturbance is the temperature difference between the drilling fluid and the downhole formation. It is critical for drilling engineers to understand this thermal impact to optimize their drilling plans. This thesis develops a numerical model using partially coupled thermoporoelasticity to study the effects of the temperature difference between the drilling fluid and formation in a drilling operation. This study focuses on the thermal impacts at the bit/formation interface. The model applies the finite-difference method for the pore pressure and temperature solutions, and the finite-element method for the deformation and stress solutions. However, the model also provides the thermoporoelastic effects at the wellbore wall, which involves wellbore fractures and wellbore instability. The simulation results show pronounced effects of the drilling fluid temperature on near-wellbore stresses. At the bottomhole area, a cool drilling fluid reduces the radial and tangential effective stresses in formation, whereas the vertical effective stress increases. The outcome is a possible enhancement in the drilling rate of the drill bit. At the wellbore wall, the cool drilling fluid reduces the vertical and tangential effective stresses but raises the radial effective stress. The result is a lower wellbore fracture gradient; however, it benefits formation stability and prevents wellbore collapse. Conversely, the simulation gives opposite induced stress results to the cooling cases when the drilling fluid is hotter than the formation.

No / Optimisation of the drilling operations is becoming increasingly important as it can significantly reduce the oil well development cost. One of the major objectives in oil well drilling is to increase the penetration rate by selecting the optimum drilling bit based on offset wells data, and adjust the drilling factors to keep the bit in good condition during the operation. At the same time, it is important to predict the bit wear and the time to pull out the bit out of hole to prevent fishing jobs. Numerous models have been suggested in the literature for predicting the time to pull the bit out to surface rather than predict or estimate the bit wear rate. Majority of the available models are largely empirical and can be applied for limited conditions, and do not include all the drilling parameters such as the formation abrasiveness and bit hydraulic. In this paper, a new approach is presented to improve the drill bit wear estimation that consists of a combination of both Bourgoyne and Young (BY) drilling rate model and theory of empirical relation for the effects of rotary speed (RPM), and weight on bit (WOB) on drilling arte (ROP) and rate of tooth wear. In addition to the drilling parameters, the formation abrasiveness and the effect of the jet impact force of the mud have also been accounted to estimate the bit wear. The proposed model enables estimation of the rock abrasiveness, and that lead to calculate the dynamic dulling rate of the bit while drilling that used in more accurate to assess the bit tooth wear compared with the mechanical specific energy (MSE). Then the estimated dulling rate at the depth of pulling out is used to determine the dull grade of the bit. The technique is validated in five wells located in two different oil fields in Libya. All studied wells in this showed a good agreement between the actual bit tooth wear and the estimated bit tooth wear.

Directional and horizontal drilling operations are increasingly conducted in all over the world, especially parallel to the growth of the technological developments in the industry. Common application fields for directional and horizontal drilling are in offshore and onshore when there is no way of drilling vertical wells. During directional and horizontal well drilling, many additional challenges occur when compared with vertical well drilling, such as limited weight on bit, harder hole cleaning, trajectory control, etc. This makes even harder to select the proper drilling parameters for increasing the rate of penetration. This study aims to propose a rate of penetration model considering many drilling parameters and conditions. The proposed model is a modified Bourgoyne &amp / Young&rsquo / s model which considers formation compaction, formation pressure, equivalent circulating density, and effective weight on bit, rotation of the bit, bit wear, hole cleaning, inclination, fluid loss properties and bit hydraulics. Also, a bit wear model is developed for roller cones and PDCs. The model performance is tested using field data obtained from several directional and horizontal offshore wells drilled at Persian Gulf. It is observed that the model can estimate rate of penetration with an error of &plusmn / 25 % when compared with the field data.

[pt] A perfuração de rochas duras ainda é um grande desafio para as empresas de perfuração e exploração de petróleo. Uma das linhas de pesquisas atuais consiste em combinar satisfatoriamente duas técnicas de aumento da taxa de penetração. Esta nova técnica vem sendo chamada de perfuração percussiva-rotativa auto-excitada. Esta dissertação se propõe a desenvolver o primeiro protótipo de um dispositivo que irá operar em ressonância e que será capaz de gerar forças dinâmicas expressivas. De forma resumida, este dispositivo será chamado de RIMD (Resonant Impact Device). Em princípio a idéia é construir um dispositivo em forma de uma caixa preta, na qual será montada na estrutura que vibra, tendo esta caixa dois ajustes, um calibrando a freqüência de ressonância do RIMD e outro agindo sobre os impactos (folga). É conhecido de trabalhos anteriores que o tamanho da folga também possui influência sobre a freqüência natural do sistema. Desta forma, existe uma interdependência entre ambos os ajustes. Um dos primeiros passos no projeto e desenvolvimento do protótipo do RIMD é o dimensionamento do mesmo, de forma que seja pequeno o suficiente para facilitar sua construção e instrumentação no laboratório de vibrações da PUC-Rio, bem como seja representativo do sistema em tamanho real (a ser implantado na coluna de perfuração). Os componentes do RIMD envolvem um sistema massa-mola com baixo amortecimento e algum dispositivo de impacto e de variação da folga. Após a concepção e construção do protótipo, os passos seguintes do estudo são a obtenção das características do RIMD, como a faixa de freqüências o qual atua e a medição das forças impulsivas geradas. Por último, o protótipo também servirá para validar um modelo analítico que permitirá investigações posteriores neste tema, podendo gerar outras possibilidades de construção do RIMD. / [en] Hard rock drilling is still a great challenge for oil companies. One current line of research involves combining the two existing drilling techniques in order to enhance the rate of penetration. This new technique is called Resonance Hammer Drilling. This dissertation proposes the design and development of the first prototype that will operate in resonance, and will be capable of generating considerable dynamic forces. This device will be known as the Resonant Impact Device, or RIMD. In principle the idea is to build some sort of black box, which will be mounted on a vibrating structure with two switches - one calibrating the RIMD resonance frequency and the other acting on the impacts - changing the size of the gap. It is known from previous work that gap size also has influence on the system natural frequency. Therefore there is a relationship between switches. One of the first steps of RIMD design and development is device dimensioning, necessary in order to construct a scale model at the Dynamic and Vibration laboratory at PUC-Rio representative of the real size system. The real size system will be mounted on the drillstring. RIMD components involve a mass-spring system with low damping and some impact and gap variation devices. The analysis of this prototype includes obtaining key characteristics such as the range of possible frequencies and the measurement of the generated impulsive forces. Finally, the built prototype will be used to validate an analytical model that will allow further investigations on this subject providing the way to other possible constructions.

[pt] Uma linha de pesquisa de grande interesse no estudo de colunas de perfuração de poços de petróleo aponta para a necessidade de se aumentar a taxa de penetração (ROP) na perfuração em rochas duras. Procurando suprir tal necessidade, este trabalho tem como objetivo estudar mecanismos e propor um novo dispositivo, utilizando as próprias vibrações geradas na coluna durante a perfuração. As várias formas de vibrar da coluna são, geralmente, indesejadas durante a perfuração. Porém, é possível utilizar algumas destas formas de vibrar para melhorar a eficiência do processo de perfuração. Inicialmente, avalia-se a influência das vibrações torcional e axial na ROP. Posteriormente, estuda-se a perfuração na ressonância e alguns aspectos e cuidados no uso desta nova técnica de perfuração, que vem sendo desenvolvida por empresas do setor. Por fim, é desenvolvido um novo dispositivo de perfuração, chamado de perfuração com martelo em ressonância ou perfuração percussiva- rotativa auto-excitada. Este dispositivo tem como premissa usar a vibração axial gerada no processo de corte, para criar uma carga harmônica na broca e excitar uma massa de aço (martelo). Desenvolve-se um modelo com vibro-impacto e atrito seco, representando o martelo e a resistência da rocha, respectivamente. Faz-se aqui, um estudo numérico e uma validação experimental do movimento percussivo de um modelo que representa a broca com este novo dispositivo. Os resultados mostram que a melhor forma do dispositivo operar é impactando a cabeça da broca, em condição de período-1, com um impacto por ciclo de forçamento. Adicionalmente, os parâmetros do experimento são identificados e os resultados numérico-experimental são comparados, mostrando que são similares. / [en] An area of interest in the study of drillstrings is due to the device of increasing the rate of penetration (ROP) in hard rocks. Trying to supply such necessity, this work aims to study mechanisms and to propose a new device, using vibrations generated in the drillstring itself. The various forms of drillstring vibrations are generally regarded as detrimental in the question. However, it is possible to use some of these vibrations forms in such a way as to enhance drilling performance. Initially, the influence of the torsional and axial vibrations in ROP is analyzed. Next, the resonance drilling, that is being developed by companies in this area, and some aspects and cares in the use of this new drilling technique are studied. At the end, a new drilling device, called resonance hammer drilling or self excited percussive rotary drilling, is developed. This device has as premise to use the axial vibration due to the cutting process, to generate a harmonic load at the bit and to excite a steel mass (hammer). A model with vibro-impact and dry friction is developed, representing the hammer and the resistance of the medium, respectively. It is presented a numeric study and an experimental validation of the percussive motion of the model, that represent the bit. The results show that the best way of the hammer to operate is impacting the bit head, in period-1 condition, ie, with one impact per cycle. Moreover, the experimental parameters are identified and since the numerical-experimental results are similar, the model used is validated.