Fundamental processes of cement hydration were studied at elevated temperatures, between 100 and 200oC at saturated steam pressure, using hydrothermal curing. Initial investigations centred on treatments on Ca3SiO5 and -Ca_2SiO_4, synthesised in the laboratory, having compositions similar to those which occur in cement clinker. Their reaction products, either separately or with blending agents such as quartz or silicic acid, were identified by x-ray diffraction. Further characterisation data were obtained for tobermorite, xonotlite, hillebrandite, gyrolite, truscottite, kilchoanite, calciochondrodite, -dicalcium silicate hydrate and tricalcium silicate hydrate using scanning electron microscopy, infrared spectroscopy and nuclear magnetic resonance spectroscopy. The current postulated structures of hillebrandite and tricalcium silicate hydrate were reassessed. The factors affecting compressive strength development of cement pastes were reviewed. Theoretical volume changes were calculated for the formation of hydrothermal calciumsilicate hydrates. These may be a useful aid in assessing the suitability of a particular phase and estimating the likely consequences of phase changes on strength. The nature of the silica source affects the type of products obtained. A more detailed study of the reaction between Ca3SiO5 and various blending agents was undertaken in order to correlate between formulation, mineralogy after hydrothermal treatment, compressive strength and porosity. Actual cement blends were studied using a typical class G oilwell cement and various blending agents. In short term tests the mineralogy and compressive strength were determined with varying compositions and temperatures. It is hoped that this information will be an aid in predicting optimum compositions by correlating properties with the nature of the materials and their chemistry. Class J cement hydration and class G cement blends were also studied by infrared and nuclear magnetic resonance spectroscopy.

Le travail de thèse a porté essentiellement sur l'effet des conditions de prise en pression et en température dans une gamme (20-60°C/Patm-200 bar) d'un ciment pétrolier (Portland « classe G ») au très jeune âge (jusqu'à un jour) en condition saturée sur (i) la cinétique d'hydratation, (ii) les propriétés hydriques (perméabilité et porosité) et (iii) le développement des propriétés élastiques dynamiques obtenues par propagation d'ultrasons et quasi-statiques. Les propriétés quasi-statiques instantanées et différées ont été obtenues à partir d'essais mécaniques réalisés en compression simple à différents temps/degré d'hydratation.La partie I a permis de montrer que la pression appliquée pendant la prise a un effet négligeable sur la cinétique d'hydratation contrairement à l'effet accélérateur de la température de prise. Un modèle de cinétique d'hydratation tenant compte de l'effet accélérateur de la température a été mis en place afin de déterminer l'évolution des fractions volumiques des différentes phases en présence dans la pâte de ciment au cours de son hydratation. L'évolution de la phase (porosité capillaire + eau) obtenue par le modèle d'évolution des fractions volumiques est en bonne concordance avec l'évolution de la porosité connectée mesuré par porosimétrie dans la deuxième partie de travail de thèse. En partie II, concernant la caractérisation de la perméabilité, les valeurs obtenues ainsi que l'évolution des propriétés élastiques quasi-statiques obtenue expérimentalement ont permis de déterminer le temps de drainage pour chacune des conditions d'hydratation étudiées. Cette information permet de déterminer la nature drainée ou non drainée des essais mécaniques quasi statiques réalisés. En partie III, les essais mécaniques ont permis d'identifier un comportement granulaire faiblement cohésif au niveau du sommet du pic exothermique, puis un comportement solide cohésif avec progression des propriétés mécaniques au cours de l'hydratation à partir de la décroissance du flux thermique. Enfin, deux modèles par homogénéisation multi-échelles ont été proposés, la différence portant sur la schématisation de la pâte de ciment au très jeune âge. Les résultats ont été confrontés avec succès aux propriétés élastiques dynamiques et quasi-statiques drainées et non drainées obtenues expérimentalement / The thesis primarily concerned the effect of the set conditions in pressure and in temperature in a range (20-60°C/Patm-200 bar) of an oilwell cement (Portland cement class G) at very early age(up to one day) in saturated condition on (I) the hydration kinetics, (II) the hydrous properties (permeability and porosity) and (III) the development of the dynamic elastic properties obtained by ultrasonic propagation and quasi-static properties. The "instantaneous" and differed quasi-static properties were obtained by mechanical tests carried out in uniaxial compression with various times/degree of hydration

Made available in DSpace on 2014-12-17T14:57:51Z (GMT). No. of bitstreams: 1 JairJF_TESE.pdf: 2222193 bytes, checksum: b572697498429b717de3a15791bc4a09 (MD5) Previous issue date: 2011-07-21 / Thermal recovery methods, especially steam injection, have been used to produce heavy oils. However, these methods imply that the metallic casing-cement sheath interface is submitted to thermal cycling. As a consequence, cracking may develop due to the thermal expansion mismatch of such materials, which allows the flow of oil and gas through the cement sheath, with environmental and economical consequences. It is therefore important to anticipate interfacial discontinuities that may arise upon Thermal recovery. The present study reports a simple alternative method to measure the shear strength of casing-sheath interfaces using pushthrough geometry, applied to polymer-containing hardened cement slurries. Polyurethane and recycled tire rubber were added to Portland-bases slurries to improve the fracture energy of intrinsically brittle cement. Samples consisting of metallic casing sections surrounded by hardened polymer-cement composites were prepared and mechanically tested. The effect of thermal cycles was investigated to simulate temperature conditions encountered in steam injection recovery. The results showed that the addition of polyurethane significantly improved the shear strength of the casing-sheath interface. The strength values obtained adding 10% BWOC of polyurethane to a Portland-base slurry more than doubled with respect to that of polyurethane-free slurries. Therefore, the use of polyurethane significantly contributes to reduce the damage caused by thermal cycling to cement sheath, improving the safety conditions of oil wells and the recovery of heavy oils / Atualmente, os m?todos com maior ?ndice de sucesso de recupera??o de ?leos pesados s?o os t?rmicos, principalmente a inje??o de vapor. Este m?todo de recupera??o coloca a interface entre o revestimento met?lico e a bainha de cimento em ciclagem t?rmica, que devido ? diferen?a de coeficientes de expans?o entre os dois materiais pode provocar o surgimento de trincas, possibilitando a passagem de fluidos pela bainha de cimento. Isto ocasiona s?rios riscos s?cio-econ?micos e ambientais. Para minimizar este problema, foi realizado um estudo que consiste em mensurar a resist?ncia ao cisalhamento entre um tubo de a?o e uma bainha de cimento. Ao material cimentante foram adicionados pol?meros, como poliuretana e borracha reciclada triturada de pneus. A adi??o de pol?meros visa melhorar a plasticidade do material cimentante e, assim, aumentar a ader?ncia da pasta endurecida sobre o revestimento, bem como a energia de ruptura do conjunto. Diante disso, a meta principal desse estudo foi avaliar a ader?ncia de comp?sitos cimentantes para po?os de petr?leo com revestimentos met?licos ap?s ciclagens t?rmicas, simulando as condi??es de varia??o de temperatura a que po?os de petr?leo s?o submetidos durante a recupera??o de ?leos pesados por m?todos t?rmicos. Observou-se que com a adi??o de poliuretana houve uma melhoria significativa da ader?ncia da interface revestimento met?lica - bainha de cimento com rela??o ? pasta padr?o, sem pol?meros. Os melhores resultados obtidos foram com pastas contendo 10% de poliuretana, que apresentaram aumento de mais de 100% na resist?ncia ao cisalhamento, em rela??o ? pasta padr?o. A adi??o de poliuretana ? pasta de cimento contribui de forma significativa para reduzir o dano causado pela ciclagem t?rmica a bainhas de cimento, melhorando a seguran?a e as condi??es de produ??o de po?os de petr?leo sujeitos ? recupera??o secund?ria por m?todos t?rmicos

[Truncated abstract] The Arabian Gulf oil and gas production reserves have made it one of the world's strategic producers since early 1960s, with many of the existing platforms stretched beyond their original design life. Advances in drilling technology and reservoir assessments have extended the requirement for the service life of those existing platforms even further. Extension of the life span of an existing platform requires satisfactory reassessment of its various structural components, including piled foundations. The American Petroleum Institute Recommended Practice 2A (API RP2A) is commonly used in the Arabian Gulf for reassessment of existing platforms. The API guidelines have been developed for conditions in the Gulf of Mexico, the waters off Alaska and the Pacific and Atlantic seaboards of the USA. However, the Arabian Gulf conditions are fundamentally different to those encountered in US waters. Hence, there is a need to develop guidelines for reassessment of existing offshore structures to account for the specific conditions of the Arabian Gulf. This thesis performs statistical analyses on databases collected during this research from existing platforms to calibrate relevant load and resistance factors for the required guidelines. The developed guidelines are based on established approaches used in developing international codes and standards such as API RP2A-LRFD. The outcome of this research revolves around the following three main issues: 1. Calibration of resistance factors for axial capacity of piles driven in the carbonate soils API RP2A (1993, 2000) does not quantify limiting soil parameters for piles driven in carbonate soils and provides a single factor to predict the capacity of piled foundations. This research identifies a set of limiting engineering parameters and calibrates corresponding capacity reduction factors to predict axial capacity of driven piles in the carbonate soils of the Arabian Gulf. ... This contrasts with Section 'R' of API RP2A (1993, 2000), which focuses on extreme environmental conditions when performing reassessment. The probabilities of failure considered in this research do not include errors and omissions (controlled by quality assurance procedures) or material deterioration (controlled by choice of materials, detailing, protective devices, and inspection and repair procedures) or reliability-based maintenance. Addressing operating overload conditions requires attending to two issues, namely the capacity of piles driven in carbonate soils and OALL, which have been addressed in this research. The operational overload situation is likely to occur during shutdown condition or during drilling or work over activities where significant OALL are usually applied to platform decks. Such operational overload can be managed by placing signs at various open areas on the platform nominating the maximum load limits (kPa), introducing procedures that ensure that maximum load limits are not exceeded during operation and management of human behavior by reinforcing the importance of following the procedures. The outcomes of this research are expected to have a profound influence on reassessment of existing platforms in the Arabian Gulf.

Made available in DSpace on 2014-12-17T14:06:55Z (GMT). No. of bitstreams: 1 CarinaGMM_DISSERT.pdf: 2881294 bytes, checksum: 3b5fb2cb077e76e3477ec04b95724ee5 (MD5) Previous issue date: 2009-12-15 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / One of the major current challenges for oilwell companies is the extraction of oil from evaporitic zones, also known as pre-salt basins. Deep reservoirs are found under thick salt layers formed from the evaporation of sea water. Salt layers seal the flow of oil from underneath rock formations, which store hydrocarbons and increase the probability of success in oil and gas exploration. Oilwells are cemented using Portland-based slurries to promote mechanical stability and zonal isolation. For pre-salt oilwells, NaCl must be added to saturate the cement slurries, however, the presence of salt in the composition of slurries affects their overall behavior. Therefore, the objective of the present study was to evaluate the effect of the addition of 5 to 25% NaCl on selected properties of Portland-based slurries. A series of tests were carried out to assess the rheological behavior, thickening time, free water and ultrassonic compressive strength. In addition, the slurries were also characterized by thermal analysis, X ray diffraction and scanning electron microscopy. The results showed that the addition of NaCl affected the thickening time of the slurries. NaCl contents up to 10% shortened the thickening time of the slurries. On the other hand, concentrations in excess of 20% not only extended the thickening time, but also reduced the strength of hardened slurries. The addition of NaCl resulted in the formation of a different crystalline phase called Friedel?s salt, where free chlorine is bonded to tricalcium aluminate / Atualmente, um dos grandes desafios para as empresas petrol?feras ? a explora??o de petr?leo em bacias dominadas por estruturas salinas, mais conhecidas por zonas evapor?ticas. A camada de sal ? formada pela evapora??o da ?gua do mar, cuja composi??o qu?mica inclui altas concentra??es de cloreto de s?dio (NaCl). Reservat?rios profundos s?o encontrados abaixo de espessas camadas de sal que vedam o fluxo de ?leo para fora da rocha, aprisionando hidrocarbonetos e aumentando, assim, a probabilidade de sucesso na prospec??o de ?leo e g?s. Atendendo ?s condi??es de po?o, s?o utilizadas pastas de cimento do tipo Portland para isolar, promover resist?ncia mec?nica ao po?o e impedir a intercomunica??o zonal das forma??es rochosas produtoras. Deste modo, as pastas de cimento devem atender ?s necessidades do sal, pois este se encontra na natureza com distintas caracter?sticas. Assim, este trabalho teve como objetivo avaliar o comportamento de sistemas de pastas saturadas com NaCl, em concentra??es de 5% a 25%, frente as propriedades f?sicas e qu?micas das mesmas. Tais propriedades foram analisadas atrav?s de ensaios laboratoriais de reologia, tempo de espessamento, ?gua livre e resist?ncia ? compress?o (UCA), bem como com o uso de t?cnicas de caracteriza??o t?rmica, difra??o de raios X e microscopia eletr?nica de varredura. Os resultados mostraram que a presen?a do NaCl, quando em pequenas concentra??es (at? 10%) atua como acelerador de pega. J? quando em altas concentra??es (a partir de 20%), n?o s? apresenta efeito oposto em rela??o ? pega, retardando-a, bem como atua deleteriamente na resist?ncia ? compress?o. Foi observada, tamb?m, a forma??o de uma nova fase denominada sal de Friedel, resultado da liga??o dos cloretos livres ao aluminato tric?lcico, incorporado ?s fases s?lidas do cimento hidratado

[pt] Uma prospecção bem sucedida de petróleo e gás requer muitos esforços para se sobrepor os desafios encontrados, tais como vibrações axiais, laterais e torcionais. Estes fenômenos podem causar a falha prematura de componentes do sistema de perfuração, disfunção nos equipamentos de medição e aumento no tempo e custo no processo de perfuração. Em particular, vibrações torcionais estão presentes em grande parte dos processos de perfuração e podem alcançar um estado crítico: stick-slip. Um melhor entendimento sobre este fenômeno proporciona ferramentas para evitar o aumento do tempo e do custo da prospecção, assegurando o investimento e sucesso do processo de perfuração. Neste trabalho, é descrito um procedimento experimental com um atrito não linear objetivando induzir stick-slip e é feito uma modelagem analítica simples do problema. O modelo de atrito é baseado em um atrito seco imposto por um dispositivo de freio desenvolvido. O comportamento não linear da bancada experimental é analisada e o modelo numérico é validado comparando diagramas de bifurcações numérica e experimentais. / [en] A successful oil and gas prospecting requires many efforts to overcome the encountered challenges, some of these challenges include drill string axial, lateral and torsional vibrations. These phenomena may cause premature component failures of the drilling system, dysfunction of measurement equipments, and increase time and costs of the prospecting process. Torsional vibrations are present in most drilling processes and may reach a severe state: stick-slip. An improved understanding about the stick-slip phenomenon provides tools to avoid the increase of prospecting time and costs, assuring the investment and success of the drilling process. Firstly, a numerical analysis of the drill string is performed with different friction models. These models are proposed in order to get familiar with the drill string dynamics. Also, it is described the experimental procedure with a nonlinear friction aiming to induce stick-slip and is performed a simple analytical modeling of the problem. The friction model is based on dry friction imposed by a break device. The nonlinear behavior of the experimental apparatus is analyzed and the numerical model is validated comparing experimental and numerical bifurcation diagrams.

[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] Parte do processo de exploração e desenvolvimento de um campo de petróleo consiste nas operações de perfuração de poços de petróleo e gás. Particularmente para poços de águas profundas e ultra-profundas, a operação requer o controle de uma estrutura muito flexível que é sujeita a condições de contorno complexas, tais como as interações não-lineares entre broca e formação rochosa ou entre a broca e a parede de poço. Quanto a esta complexidade, o fenômeno stick-slip é um componente primordial relacionado à vibração torsional. Este pode excitar vibrações tanto axiais quanto laterais. Isso pode causar falha prematura de componentes de corda de perfuração. Assim, a redução e eliminação de oscilações do tipo stick-phase são itens muito valiosos em termos de economia financeira e de tempo de exploração. Com este propósito, este estudo tem como principal objetivo confrontar o problema de vibração torsional simulando uma estratégia de controle robusto em tempo real. A abordagem é obtida seguindo alguns passos, tais como: análise em malha aberta do sistema de perfuração considerando um atuador top drive e o sistema de coluna de perfuração; concepção de um novo controlador que utiliza diferentes velocidades angulares de referência num sistema de controle de malha fechada; controle da vibração torsional considerando a não-linearidade devida à interação de atrito na parede do poço e no fundo do poço; avaliar por meio de simulações sistemas de controle ininterruptos durante a perfuração; validação dos modelos por meio de simulações numéricas. Esta dissertação apresenta a base teórica por trás do sistema de perfuração, bem como exemplos de resultados numéricos que proporcionam uma operação de perfuração controlada estável e satisfatória. / [en] Part of the process of exploration and development of an oil field consists of the drilling operations for oil and gas wells. Particularly for deep water and ultra deep water wells, the operation requires the control of a very exible structure which is subjected to complex boundary conditions such as the nonlinear interactions between drill bit and rock formation and between the drill-string and borehole wall. Concerning this complexity the stick-slip phenomenon is a major component, related to the torsional vibration and it can excite both axial and lateral vibrations. That may cause premature failure of drill-string components. So, the reduction and avoidance of stickslip oscillations are very valuable items in terms of savings and exploration time. With these intentions, this study has the main goal of confronting the torsional vibration problem using a real-time robust control strategy. The approach is obtained following some steps such as: Open-loop analysis of the drilling system considering a top-drive actuator and the drill-string system; Design of a novel controller using different angular velocity setpoints in a closed-loop system; Control of the torsional vibration considering the nonlinearity due to friction interaction in the wall and in the donwhole system; valuate a non-stop control system while drilling; Verification by numerical simulations. In this presentation the theoretical basis behind the drilling system will be given, as well examples of numerical results providing a stable and satisfactory controlled drilling operation.

[pt] Esta dissertação estuda o comportamento dinâmico não linear de colunas de perfuração de poços de petróleo. A coluna de perfuração é uma estrutura longa, flexível e esbelta, responsável pela perfuração propriamente dita. Seus elementos e funções são apresentados e uma análise numérica é realizada posteriormente. Foi desenvolvido um programa utilizando o software MATLAB (marca registrada) para simulação numérica do comportamento dinâmico das colunas pelo método dos elementos finitos que utiliza a formulação corotacional para implementação da não linearidade geométrica. A discretização da estrutura utiliza um elemento de viga com seis graus de liberdade por nó aplicando a formulação de viga de Euler-Bernoulli. Para solução do sistema de equações não lineares resultante utiliza-se o método de Newton-Raphson. Além disso, o método de Newmark é utilizado para integração no tempo das equações de movimento do problema. Um modelo com molas lineares é proposto para representar o contato entre a parede do poço e a coluna. A metodologia proposta e as funcionalidades do programa desenvolvido são avaliadas e seus resultados são comparados com algumas soluções analíticas ou numéricas de exemplos disponíveis na literatura. Esses resultados conferem confiabilidade na análise de problemas de coluna de perfuração, que apresentam as séries temporais de deslocamentos e esforços em toda a coluna e os modos de flambagem gerados. Os resultados obtidos demonstram que a coluna é muito sensível a qualquer mudança de condição de contorno, o que corrobora com a complexidade do problema. Assim, o trabalho fornece uma base razoável para desenvolvimentos posteriores, que permitam a análise de toda a coluna de perfuração acoplada. / [en] This work studies the nonlinear dynamic behavior of oil well drillstring, which is a long slender flexible structure responsible for the drilling. Its elements and functions are presented, and numerical analyses are performed later. The work develops a computational code using the software MATLAB (trademark) for the numerical simulation of the column s dynamic behavior using the finite element method. The corotational formulation is used for the implementation of geometric nonlinearity. The structure s discretization uses a beam element with six degrees of freedom per node and employs the Euler-Bernoulli s beam formulation. The Newton-Raphson method is responsible for solving the nonlinear system of equations. In addition, the solution procedure uses the Newmark s method for the time integration of the problem s movement equations. A linear setup spring model is proposed to represent the contact between the borehole wall and the column. The proposed methodology and computational code capabilities are evaluated by comparing some results to analytical or numerical results of examples available in the literature. These results give reliability to analyze drillstring problems, which present the displacements and forces time series of the whole column and the buckling modes generated. The results show that the column is very sensitive to any boundary condition changing, which corroborates the complexity of the problem. Hence, the work proposes a reasonable basis for further developments, allowing the entire coupled drillstring analysis.

Made available in DSpace on 2014-12-17T14:06:44Z (GMT). No. of bitstreams: 1 TulioWBJ.pdf: 572575 bytes, checksum: 5effde52c942d11015aa333c7bd07b5f (MD5) Previous issue date: 2008-02-29 / Oil well cementing materials consist of slurries of Special class Portland cement dispersed in water. Admixtures can be used to provide the necessary fluidity, so the material can be efficiently pumped down as well as penetrate porous rocks with controlled filter loss. Construction admixtures can be used to modify the properties of oil well cements provided they can withstand and hold their properties at the higher than ambient temperatures usually encountered in oil fields. In civil construction, superplasticizer play the role of dispersants that reduce the facto r of water cement improve mechanical properties and fluidity of the cement, whereas anti-segregation agents improve the workability of the slurry. In the present study, oil well cement slurries were produced adding both a dispersant and an anti-segregation agent conventionally used in Portland CPII-Z-32 RS cement aiming at materials for primary cementing and squeeze operations. Three basic aspects were evaluated: fluidity, filter loss and the synergetic effect of the admixtures at two temperatures, i.e., 27?C and 56?C, following API RP 10B practical recommendations. The slurries were prepared using admixture concentrations varying from 2.60 Kgf/m3 (0.02 gallft3) to 5.82 Kgf/m3 (0.045 galJft3) BWOC. The density of the slurries was set to 1.89 g/cm3 (15.8 Ib/gal). 0.30 to 0.60% BWOC of a CMC-based anti-segregation agent was added to the cement to control the filter loss. The results showed that the addition of anti-segregation at concentrations above 0.55% by weight of cement resulted in the increased viscosity of the folders in temperatures evaluated. The increasing the temperature of the tests led to a reduction in the performance of anti-segregation. At concentrations of 5.20 kgf/m3 (0,040 gallft3) and 5.82 Kgf/m3 (0,045 gal/ft 3) observed a better performance of the properties evaluated in the proposed system. At low temperature was observed instability in the readings of rheology for all concentrations of anti-segregation. Contents that increasing the concentration of anti?-segregation is limited concentrations greater than 0.55 % BWOC of the CMC in temperature analyzed. The use of the system with CMC promoted a good performance against the properties evaluated. The principal function of anti?-segregation was optimized with increasing concentration of superplasticizer, at temperatures above the 2rC. The study of the behaviour of systemic additives, resulting in slurries of cement, which can be optimized face studies of other intrinsic properties in oil fields / A pasta de cimento Portland ? uma mistura de part?culas s?lidas de cimento dispersas em ?gua. Tal sistema deve possuir fluidez suficiente para penetrar de forma eficiente em meio poroso, al?m de proporcionar controle na ?gua perdida por filtrado na forma??o, garantindo o sucesso da opera??o de bombeio. Em determinados campos as condi??es geol?gicas das forma??es, bem como a profundidade das faces explorat?rias do po?o podem favorecer ao acr?scimo de temperatura. Na constru??o civil os superplastificantes reduzem o fator ?gua cimento das argamassas proporcionando aumento de propriedades como resist?ncia mec?nica e fluidez, j? o anti-segregante proporciona uma melhor trabalhabilidade das argamassas. Sistemas com a adi??o de dispersantes e anti?segregante utilizados convencionalmente em cimento Portland CPII-Z-32 RS foram analisados em pastas de cimento Portland Especial, utilizadas para opera??es de squeeze e cimenta??o em po?os petrol?feros, com ?nfase em tr?s aspectos: fluidez, perda do volume de filtrado e efeito sinerg?tico. Os par?metros analisados foram estudados por meio de ensaios de desempenho nas temperaturas de 2rC e 56?C, seguindo as recomenda??es pr?ticas da norma API RP 108. Para o estudo foram selecionados materiais com car?ter dispersante como superplastificantes. e preparadas pastas com concentra??es variando de 2,60 Kgf/m3 (0,02 gal/p?3) a 5,82 Kgf/m3 (0,045 gal/p?3) em peso de cimento, com densidade constante de 1,89 g/cm3 (15,8 Ib/gal). Para o controle da ?gua perdida por filtra??o foi utilizado um agente anti-segregante a base de CMC com concentra??es variando de 0,30 % a 0,60 % em peso de cimento. Os resultados mostraram que a adi??o do anti-segregante em concentra??es acima de 0,55 % em peso de cimento resultou no aumento da viscosidade das pastas nas temperaturas avaliadas. Foi verificado que o aumento da temperatura dos testes provocou uma redu??o no desempenho do anti-segregante. Nas concentra??es de 5,20 kgf/m3 (0,040 gal/p?3) e 5,82 Kgf/m3 (0,045 gal/p?3) observou-se um melhor desempenho das propriedades avaliadas no sistema proposto. Na temperatura ambiente foi verificado instabilidade nas leituras de reologia para todas as concentra??es do anti-segregante. Foi verificado que o aumento da concentra??o de anti-segregante ? limitada as concentra??es superior a 0,55 % em peso de cimento nas temperaturas analisadas. O uso do sistema contendo superplastificante, aliado ao anti-segregante promoveu um bom desempenho face ?s propriedades reol?gicas e de controle de filtrado das pastas. A fun??o principal do anti-segregante foi otimizada com o aumento da concentra??o do superplastificante, a temperaturas acima da ambiente. Por?m o aumento da concentra??o do agente dispersante nas pastas de cimento pode provocar o retardamento das pastas em temperaturas pr?ximas da ambiente. O estudo do comportamento sist?mico dos aditivos resultou na obten??o de pastas de cimento, que podem ser otimizadas face estudos de outras propriedades intr?nsecas a sua utiliza??o nas opera??es em campos petrol?feros