Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 126-128).

Thesis (M.S. in environmental science)--Washington State University, August 2007. / Includes bibliographical references (p. 19).

Today, drilling can be considered the most common of all metal cutting operations. Drilling can be accomplished on nearly all machines that can produce a relative rotation of the spindle, and/or the workpiece. These machines can include drill presses, lathes, milling machines and machining centers. Of the more than 1.70 million machine tools in the United States, that are located in plants employing more than twenty workers, more than half of these machines can, and probably are performing drilling functions. Drilling has been studied in numerous investigations with the objective of increasing drill performance. Severely lacking in this research has been the use of statistically designed experiments. Traditional experimental techniques in tooling have been conducted under a one variable at a time methodology. The twist drill, however, is one of the most complex metal cutting tools in existence today. Changing one variable at a time can lead to unwanted changes in other variables. With today's statistical techniques and computers, variables and variable interactions should be able to be adjusted and controlled. Because drilling is one of the leading metal cutting operations, an ever so slight increase in the level of drill performance could yield important benefits to manufacturing. Investigation into drill geometry and variable interaction may also lead to significant increases in drill performance. A quantitative analysis was performed to determine the effect of different independent variables on tool life for Titanium Nitride Coated tools. This was accomplished in two stages. In Stage 1, the variables lip height, helix angle, and margin width were tested one at a time for their effect on tool life. In Stage 2, the variable lip height from Stage 1 and the independent variables, speed and feed, were tested for their effect on tool life in a three variable, two level factorial treatment design. Secondary measurements were also taken in Stage 2 on acceleration, torque and face wear. Stage 1 showed that tighter tolerances on lip height could improve tool life. The 39 degree helix angle was more of a detriment than an aid, to increase tool life. The lowest level of margin width had lower tool life than either of the other two levels. In stage 2 feed and lip height had a significant effect on tool life at the 90% confidence level. Speed did not have an effect on tool life. No variable in Stage 2 had an significant effect on acceleration at either the 95% or 90% confidence level. At the low level of the feed, acceleration readings seemed applicable in determining pending tool failure. The largest values of crater width on the face were associated with the low values of feed. No true distinction can be made with torque, between any of the combinations of levels tested. This research has attempted to further quantify some of the variables and variable interactions associated with drilling for Titanium Nitride Coated tools. / M.S.

This thesis presents a detailed analysis of the plane rake faced drill design, its grinding method and grinding wheel geometry. A fundamental geometrical analysis has then been carried out on the major cutting edges of the modified drills according to the national and international standards. It has been shown that this new drill design results in a significant increase in the normal rake angle at lips as well as point relieving at the chisel edge region. Geometrical models for the various drill point features have been established which uniquely define the drill point features of the modified drill design. A comprehensive experimental investigation has been carried out to study the drilling performance of the modified drills, when drilling a high tensile steel, ASSAB 4340, with TiN coated high speed steel drills over a wide range of drilling conditions. Comparing to the drilling performance with conventional twist drills under the corresponding conditions, it has been found that the modified drills can reduce the thrust force by as much as 46.9% with the average of 23.8%; the reduction of drilling torque is also significant at an average of 13.2% and the maximum of 24.9%. Similarly, the new drill design shows great superiorities over the conventional drills in terms of drill-life. In the drill-life tests, a few conventional drills were broken, but all plane rake faced drills performed very well. In order to estimate the cutting performance in process planning on a mathematical and quantitative basis when drilling with the modified drills, predictive cutting force models have been developed based on the unified-generalized mechanics of cutting approach. The models have been assessed qualitatively and quantitatively and showed good agreements with the experimental thrust, torque and power. Empirical-type force equations have also been developed to provide simple alternatives for practical applications.

This thesis presents a detailed analysis of the plane rake faced drill design, its grinding method and grinding wheel geometry. A fundamental geometrical analysis has then been carried out on the major cutting edges of the modified drills according to the national and international standards. It has been shown that this new drill design results in a significant increase in the normal rake angle at lips as well as point relieving at the chisel edge region. Geometrical models for the various drill point features have been established which uniquely define the drill point features of the modified drill design. A comprehensive experimental investigation has been carried out to study the drilling performance of the modified drills, when drilling a high tensile steel, ASSAB 4340, with TiN coated high speed steel drills over a wide range of drilling conditions. Comparing to the drilling performance with conventional twist drills under the corresponding conditions, it has been found that the modified drills can reduce the thrust force by as much as 46.9% with the average of 23.8%; the reduction of drilling torque is also significant at an average of 13.2% and the maximum of 24.9%. Similarly, the new drill design shows great superiorities over the conventional drills in terms of drill-life. In the drill-life tests, a few conventional drills were broken, but all plane rake faced drills performed very well. In order to estimate the cutting performance in process planning on a mathematical and quantitative basis when drilling with the modified drills, predictive cutting force models have been developed based on the unified-generalized mechanics of cutting approach. The models have been assessed qualitatively and quantitatively and showed good agreements with the experimental thrust, torque and power. Empirical-type force equations have also been developed to provide simple alternatives for practical applications.

Thesis. 1977. Mech.E.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by K. Subramanian. / Mech.E.

published_or_final_version / Applied Geosciences / Master / Master of Science

Orientador: João Andrade de Carvalho Junior / Coorientador: Andreas Nascimento / Banca: Mauro Hugo Mathias / Banca: José Luiz Gonçalves / Abstract: To meet the increasing primary energy demand, more challenging petroleum reserves started being explored, such as the reservoirs from pre-salt formation close to the Brazilian and Angolan coasts. Historically, low penetration rates in drilling the pre-salt carbonates were reported in the literature, resulting in large capital expenditure on well's construction. Since the major part of exploration cost is associated with drilling, optimizing this activity is of major importance. In this context, the main objective of the present thesis is to investigate methods for real-time drilling optimization of oil and natural gas wells. A common way to optimize drilling activities is to determine the optimum operational variables (e.g. weight-on-bit and rotational speed) that maximizes the ROP. However, this may yield a decrease in drilling efficiency. An alternative to reduce problems related to drilling inefficiency, such as excessive bit wear and vibrations, is through the selection of operational variables able to minimize the specific energy (SE) spent to excavate a volumetric unit of rock. For that, it is necessary to employ accurate predictive models able to capture how the operational variables (weight-on-bit, rotational speed, mud flow and so on) influence not only on ROP but also on SE. Therefore, the present thesis employed a well-known machine learning method, called random forest, instead of analytical equations found in drilling engineering books. Thus, it was possible to o... (Complete abstract click electronic access below) / Resumo: Para atender à crescente demanda de energia primária, começaram a ser exploradas reservas de petróleo em áreas mais desafiadoras, tais como os reservatórios da formação do pré-sal próximos às costas brasileira e angolana. Historicamente, observa-se baixa taxa de penetração na perfuração dos carbonatos do pré-sal, resultando em altos custos na construção de poços. Como a maior parte dos custos de exploração está associado com perfuração, a otimização desta atividade é de grande importância. Neste contexto, o principal objetivo desta dissertação é investigar métodos de otimização em tempo-real de poços de petróleo e gás natural. Uma forma comum de se otimizar a perfuração é através da determinação dos parâmetros operacionais (peso na broca e rotação) que maximizem a taxa de penetração (rate of penetration, ROP). Contudo, isto pode acarretar na diminuição da eficiência do processo de perfuração. Assim, uma forma de diminuir problemas relacionadas a ineficiências da perfuração, tais como gasto excessivo da broca ou vibrações, é através da seleção dos parâmetros operacionais, minimizando a energia específica (specific energy, SE) gasta para escavar uma unidade volumétrica de rocha. Para tanto, é necessário o emprego de modelos precisos que relacionem como as variáveis operacionais (peso da broca, rotação, vazão do fluido de perfuração entre outros) influenciam, não somente o ROP, mas também a SE. Desde modo, a presente dissertação empregou um método conhecido de aprendizagem de má... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

A study of the Strategic Sewage Disposal Scheme (SSDS) Stage 1 Tunnel F in Hong Kong was carried out as it is a great example of deep sub-sea hard rock TBM tunnelling through unfavourable, fault-affected ground conditions with heavy water inflows. The main objective of this study was to document events that took place during Tunnel F excavation and collate geological and geotechnical data related to the excavation, to aid future tunnel designers and contractors to assess the risk involved with such tunnelling projects. Data relevant to Tunnel F was collected from many personnel involved with the excavation, and from the Hong Kong Geological Survey (HKGS) of the Geotechnical Engineering Office. Geological maps, ground investigation data, tunnel mapping records, ground water inflow records and grouting records were reviewed and used to summarise the ground conditions and to analyse various potential relationships. Knowledge of ground conditions is the most important requirement for any tunnelling project. This dissertation addresses the differences between actual and predicted ground conditions and the consequences of lack of ground investigation data. The major difference between predicted and observed ground conditions during Tunnel F excavation was the amount of water ingress into the tunnel. Hundreds of liters per minute of water at up to 13bar pressure was encountered from a few probe and grout holes. In the Tolo Channel Fault area, low Q values and very high ground water inflows were experienced, and heavy temporary support and large grout volumes were required to complete the tunnel. / published_or_final_version / Applied Geosciences / Master / Master of Science

Mechanical vibrations are inevitable in drilling operations. Torsional stick-slip vibrations are vibrations that occur in drilling columns, which are produced by periodic variations of torque and characterized by large fluctuations in the speed of the drill bit. These vibrations are dangerous, primarily by the cyclical characteristic of the phenomenon that by the amplitude of the same, which can cause fatigue of the pipe, failures in the components of the drill string, deformations in the walls of the well, excessive wear of the drill, low rate of penetration, and collapse of the drilling process. The frequency of these unwanted oscillations can be reduced by the application of automatic control techniques. The objective of this study is to evaluate through numerical simulations, the application of conventional control techniques, such as proportional-integral control (PI), and nonlinear, as the sliding mode control (SMC) and the input-output linearization control (IOLC), to eliminate the presence of stick-slip oscillation in drilling columns. The controllers are designed primarily to maintain a constant speed of rotation system, by manipulating engine torque, thereby inferentially control the speed of the drill, thus providing optimum operation conditions, beyond preserving system stability. Results of simulations using drill string torsional models of two degrees of freedom (2-DOF) and four degrees of freedom (4-DOF) show the performance of the proposed control systems, which are analyzed and qualitatively compared. / Vibrações mecânicas são inevitáveis nas operações de perfuração. Vibrações torcionais stick-slip são vibrações que ocorrem em colunas de perfuração, as quais são produzidas pelas variações periódicas de torque e caracterizadas por grandes oscilações da velocidade da broca. Estas vibrações são prejudiciais, mais pela característica cíclica do fenômeno que pela amplitude da mesma, podendo originar fadiga da tubulação, falhas nos componentes da coluna de perfuração, deformações nas paredes do poço, desgaste excessivo da broca, baixa taxa de penetração e, inclusive, colapso do processo de perfuração. A frequência destas oscilações indesejadas pode ser reduzida pela aplicação de técnicas de controle automático. O objetivo deste trabalho é avaliar, mediante simulações numéricas, a aplicação de técnicas de controle convencional, como o controle proporcional-integral (PI), e não linear, como o controle por modos deslizantes (SMC) e o controle por linearização entrada-saída (IOLC) para eliminar a presença de oscilações stick-slip em colunas de perfuração. Os controladores são desenvolvidos principalmente para manter constante a velocidade do sistema de rotação, mediante a manipulação do torque do motor, para assim controlar inferencialmente a velocidade da broca, fornecendo desta maneira condições ótimas de operação, além de preservar a estabilidade do sistema. Resultados das simulações, usando modelos torcionais de uma coluna de perfuração de dois graus de liberdade (2-DOF) e de quatro graus de liberdade (4-DOF), mostram o desempenho dos sistemas de controle propostos, os quais são analisados e comparados qualitativamente.