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.

No description available.

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1949. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed July 8, 2010) Includes bibliographical references (p. 47) and index (p. 48-52).

The incompatibility of cement and shale and the subsequent failure of primary cementing jobs is a very significant concern in the oil & gas industry. On wells ranging from hydraulically fractured shale land wells to deepwater wells, this incompatibility leads to an increased risk in failing to isolate zones, which could possibly present a well control hazard and can lead to sustained casing pressure. The cement-shale interface presents a weak link that often becomes compromised by the loads incurred either during drilling, completion/stimulation or production phases. To formulate cements for effective zonal isolation, it is crucial to evaluate the bond strength of the cement-shale interface. Although several studies have focused on the interactions between cement and sandstone, very few studies have addressed the bonding behavior of cement with shale. The conventional push-out test protocol used to measure cement-to-sandstone shear bond strength has proven to be difficult to apply on shale due to its laminated or brittle nature that complicates sample preparation and can lead to shale or cement matrix failure instead of failure at the interface. In this paper, we present a novel, simple and versatile laboratory test procedure to measure the shear bond strength between cement and shale. The new procedure was used to develop cement formulations to improve the cement-to-shale bond. Two different design approaches were investigated. One involves introducing Gilsonite into cement to maintain shale integrity. The second design involves using surfactant to improve cement interfacial sealing property. Our results indicate that bond strength of cement with shale can be enhanced significantly incorporating surfactant in cement slurries. / text

Objetivo: Avaliar a influência de diferentes tratamentos de superfície da zircônia na rugosidade superficial e na resistência de união utilizando diferentes agentes de cimentação, pré e pós-ciclagem térmica, bem como analisar a superfície de fratura. Metodologia: Foram elaborados três artigos científicos. No Capítulo 1, apresentou-se um estudo de revisão da literatura a respeito dos métodos de tratamento de superfície e os diferentes tipos de cimentos indicados para proporcionar união adesiva entre a zircônia e materiais resinosos. No Capítulo idade da superfície modificada e a resistência da união entre cerâmica e material resinoso. Os tratamentos de superfície analisados foram: jateamento com partículas de Al2O3 de 50μm, aplicação de primer contendo MDP, silicatização e silicatização associado a aplicação de primer contendo MDP, além da associação de dois tipos de cimentos resinosos, cimento resinoso modificado com monômeros fosfatados e cimento resinoso autoadesivo. Foi utilizado o teste de rugosidade e de microcisalhamento para verificar a alteração de superfície e a força de adesão proporcionada pelos grupos experimentais seguidas de análise do modo de falha para verificar as características da interface adesiva. No capítulo 3 foi realizado o mesmo delineamento do Capítulo 2, entretanto, foi associado o processo de ciclagem térmica para verificação do comportamento dos diferentes tratamentos de superfícies e materiais cimentantes, com intuito de simular parcialmente condições clínicas. Conclusões: Ambos os cimentos utilizados podem ser indicados para a cimentação adesiva da cerâmica a base de zircônia. Em relação aos cimentos resinosos modificados o tratamentos de superfície apresenta-se indispensável para possibilitar melhora na resistência de união. O tratamento com a cobertura de sílica associado ou não ao primer apresentou-se com melhores resultados. Em relação aos cimentos autoadesivos o tratamento de superfície não teve grande influência na resistência de união, porém melhores resultados foram obtidos nas superfícies tratadas com a cobertura de sílica. Após a ciclagem térmica foi observado que o cimento autoadesivo apresentou melhores valores de força de adesão em comparação ao cimento resinoso modificado, independente do tratamento de superfície realizado. / Objective: To evaluate the influence of different surface treatments of zirconia in surface roughness and bond strength using different cementing agents, before and after thermal cycling as well as analyze the fracture surface. Methods: We developed three papers. In Chapter 1, presented a study of the review of the literature on the methods of surface treatment and different types of cements indicated for providing bonding between zirconia and resin materials. In Chapter 2, an experiment was designed to evaluate the influence of different types of surface treatment of ceramic and cement types on the surface roughness of the modified surface and the bond strength between compositive material and ceramics. The w yz w h A O3 50μ applying primer containing MDP, and silicatization associated with applying primer containing MDP. A resin cement modified with phosphate monomers and self-adhesive resin cement were also analyzed. Roughness and microshear test was used to verify the change of surface, and the adhesion strength provided by the experimental groups followed by analysis of the way to check the characteristics of the adhesive interface. The analyzed results were submitted to statistical analysis. In chapter 3 was used the same design done in Chapter 2, however, thermal cycling process was associated to verify the behavior of different surface treatments and materials with the aim of partially simulate clinical conditions. Conclusions: Both cements used might be indicated for the adhesive cementation of zirconia-based ceramics. Regarding resin cements modified the surface treatment has become indispensable to enable improvement in bond strength. Treatment with silica coverage with or without the primer presented with better results. Regarding the self-adhesive cement, surface treatment had no major influence on the bond strength but better results were obtained on surfaces treated with the coverage of silica. After thermocycling was observed that the self-adhesive cement had values better adhesion strength in comparison to the modified resin cement.

[pt] Este estudo tem como objetivo avaliar a influência do desenvolvimento das propriedades mecânicas da pasta de cimento na integridade do poço de petróleo. Um modelo numérico foi desenvolvido para simular as diferentes fases de construção de poços, tais como perfuração, ação da fluência, reconstrução do revestimento e a hidratação do cimento. O comportamento da fluência do sal foi modelado através uma metodologia que combina o Duplo Mecanismo e a Lei da Potência. Duas fases foram consideradas para a pasta de cimento. Em primeiro lugar, a pasta de cimento foi idealizada como um fluido com um campo de tensão hidrostática. Durante as primeiras cinco horas após a cimentação, uma diminuição do campo de tensão hidrostática foi utilizada a fim de simular a retração autógena e a perda de água no processo. Quando a pasta de cimento foi considerada como elástico com um módulo de rigidez crescente ao longo do tempo quando solidificada. Na mudança de fase do fluido para sólido, um cuidado especial foi dado aos elementos que representam a pasta de cimento hidratada a fim de evitar a sobreposição de malhas. A nova lei de fluência do sal apresentou resultados precisos quando comparado aos valores obtidos em campo e a outros dados encontrados na literatura. No processo de hidratação, a redução das dimensões anulares foi observada. A taxa de deformação diminuiu com o aumento do módulo de rigidez da pasta de cimento. Mais importante ainda, esta deformação foi insignificante quando comparada com as dimensões do poço. Assim, a solidificação do cimento pode ser desconsiderada em simulações expeditas. / [en] The quality of the cement sheath plays a crucial role in the integrity of the oil well. This study aims at assessing the influence of cement hardening on deformations and stresses to which the sheath is submitted. A numerical model was developed to simulate the different stages of well construction such as drilling, creep action, casing reconstruction and - the focus herein - cement hardening. The salt creep behavior was modeled through a new methodology that combines the Double Mechanism with the Power Law. Two stages were considered for the cement. First, the cement was idealized as a fluid with a hydrostatic stress field. During the first five hours after cementation, a decrease in the hydrostatic stress field was employed in order to simulate the chemical shrinkage and loss of water in the hardening process. When hardened, the cement was considered to behave elastically with an increasing stiffness modulus over time. In the phase change from fluid to solid, special care was given to fitting the cement finite element mesh to the annulus, avoiding mesh overlapping. The new salt creep law showed accurate results when compared to field and other creep data. In the hardening process, the annular dimension reduction was expected and noticed. The deformation rate decreased with the increasing cement stiffness modulus. Most importantly, this deformation was negligible when compared with the dimensions of the well. Moreover, for practical and quick simulations, the hardening step can be avoided.

La carbonatation atmosphérique et la pénétration des ions chlorures sont les principales causes du déclenchement de la corrosion des armatures dans les bétons armés. Chacun de ses mécanismes a fait l'objet de nombreuses études dans la bibliographie. Pourtant les études prenant en compte en même temps les deux types d'agression sont rares. Le couplage des deux phénomènes existe cependant. La carbonatation intervient en effet dans tout ouvrage dès le décoffrage et il suffit que cet ouvrage soit aussi par exemple situé à proximité d'eau de mer pour que les embruns apportent des ions chlorures dans le matériau. L'objectif de cette thèse a été de quantifier les différentes phases de la matrice cimentaire et ses capacités de fixation des ions chlorures par le biais d'isothermes d'interactions pour des matériaux sains et carbonatés. Ces isothermes d'interactions obtenues notamment par la méthode des équilibres ont permis de voir que les matrices partiellement ou totalement carbonatées fixaient moins d'ions chlorures que les matrices saines. L'utilisation de moyens complémentaires d'analyses tels que l'analyse thermogravimétrique (ATG), la diffraction des rayons X (DRX) et la résonance magnétique nucléaire (RMN) a permis de mieux comprendre cette perte de fixation. Une diminution des sels de Friedel et des chlorures fixés par les C-S-H a été ainsi mise en évidence dans les matériaux carbonatés. Ces diminutions qui on été quantifiées sont attribuées à une modification sous carbonatation des phases capables de fixer les ions chlorures (phases aluminates, sulfo-aluminates et C-S-H). Des différences au niveau du réseau poreux ont été également mises en évidence par la porosimétrie par intrusion de mercure (diminution de la macroporosité et de la connectivité en général pour les matrices carbonatées par formation de CaCO3). L'objectif a été aussi de corréler toutes ces modifications observées avec les propriétés de transport des ions qui ont été obtenues par des tests de diffusion et migration des ions chlorures (et/ou sulfates) ainsi que des mesures de résistivité électrique. Les résultats expérimentaux ont montré que le coefficient de diffusion apparent est plus grand dans les matériaux carbonatés. Certaines expériences de diffusion faites en présence à la fois d'ions chlorures et sulfates ont aussi montré la concurrence de ces deux ions pour se fixer à la matrice cimentaire. Les matériaux cimentaires testés (bétons et pâtes) ont été formulés sans ou avec additions minérales (métakaolin, cendres volantes, laitier) et les propriétés de ces matériaux ont été observées à différents âges / Carbonation and chloride ingress are the main causes of reinforced concrete degradation. A lot of studies describe these two phenomena separately but only few studies state a possible coupling. However, the coupling of both phenomena exists. The corrosion of reinforcement due to chloride ions occurs more often in marine environments or in the presence of deicing salts while carbonation occurs systematically, in a more or less high degree depending on environmental conditions (humidity, temperature…). The aim of this thesis was to quantify the different phases of the cement matrix and its chloride binding by means of chloride binding isotherms for carbonated and non-carbonated cement based materials. These chloride binding isotherms, obtained by the equilibrium method, showed that the partially or totally carbonated cement matrix are bound fewer chlorides than the non carbonated ones. Complementary techniques such as the thermogravimetry (TGA), the X-rays diffraction (XRD) and the nuclear magnetic resonance (NMR) analyses were used and allowed to understand why this binding decrease occurs. A decrease of Friedel's salt and chlorides bound in the C-S-H was showed in the carbonated materials. These decreases were quantified and are due to a modification of the phases containing chloride (such as aluminates, sulfo-aluminates and C-S-H phases) during carbonation process. The porous network, was observed by mercury intrusion porosimetry (MIP), was also modified (decrease of the macroporosity and the connectivity for carbonated cement matrix due to formation of calcium carbonate). The other aim was to correlate all these modifications with the ions transport properties. Chloride diffusion and migration tests (with or without sulfates) were obtained as well as the measurements of electric resistivity. The experimental results showed that the apparent chloride diffusion coefficient is higher in the carbonated cement materials. Some diffusion tests were performed in presence of both chlorides and sulfates, which showed the competition of these two ions to bind on the cement matrix. Cement materials (concrete and cement paste) were designed without or with supplementary cementing materials (metakaolin, fly ash, slag) and the properties of these materials were followed at different curing time

The objective of this study was to compare effect of surface treatment and fatigue to the retention of zirconia crowns luted to two different heights of titanium abutments. Thirty titanium base 3.5 mm (n = 15) and 5.5 mm in height (n = 15) and thirty zirconia crowns were used. Group A (n = 10), 3.5-mm-height titanium base with no surface treatment; Group B (n = 5), 3.5-mm-height titanium base with surface treatment; Group C (n = 5), 3.5-mm-height titanium base with no surface treatment with fatigue test; Group D (n = 5), 3.5-mm-height titanium base with surface treatment and fatigue test. The identical group allocation was utilized to 5.5-mm-height titanium base groups, Group E, F, G and H respectively. All zirconia crowns and titanium abutments of the groups with surface treatment were particle abraded with 50 μm alumina. All specimens were subjected to a pull-out test. Data were analyzed with ANOVA and the Tukey HSD test. Pull-out retention forces for each group were: Group A: 288 ± 97.5 N, Group B: 198.71 ± 82.94 N, Group C: 537.61 ± 80.13 N, Group D: 600.11 ± 27.23 N, Group E: 240.68 ± 54.33 N, Group F: 270.92 ± 16.43 N, Group G: 707.03 ± 32.30 N, and Group H: 831.19 ± 55.50 N. Particle abrasion of the titanium base significantly increased zirconia crown retention. The height of the titanium base had a significant influence on retention force in particle-abraded groups. The fatigue test did not decrease retention force. / 2018-09-26T00:00:00Z

[pt] Após a perfuração de poços de petróleo, a lama utilizada na remoção de cascalho, lubrificação e resfriamento da broca deve ser removida e substituída por uma mistura de cimento. Essa substituição se dá pelo deslocamento de um fluido por outro no espaço anular entre a formação rochosa e a coluna de completação ou revestimento. A mistura de cimento tem a função de garantir a estabilidade estrutural do poço evitando danos ambientais e prejuízos econômicos. Para melhores resultados do processo de cimentação, utilizam-se fluidos intermediários, também chamados de colchões lavadores e espaçadores, entre os fluidos principais. A boa qualidade do deslocamento dos fluidos pode ser avaliada pela forma da interface entre eles. Perfis mais acentuados sugerem um atravessamento indesejável do fluido deslocante (cimento) através do deslocado (fluido de perfuração). Por outro lado, perfis achatados indicam um deslocamento mais eficiente. Neste trabalho foi feita uma análise experimental e numérica do processo de cimentação, investigando a forma da interface e a eficiência do deslocamento dos fluidos. Uma planta experimental vertical foi construída, simulando um processo de deslocamento de fluidos em anulares excêntricos de poços. Com uma câmera digital CCD foram filmadas as interfaces entre os fluidos durante o escoamento e com essas imagens puderam-se comparar os resultados com as simulações numéricas realizadas num softw are comercial, usando o método de volumes finitos. Foram analisados os efeitos de diferentes parâmetros como a excentricidade, o regime de escoamento, e, principalmente o comportamento mecânico dos fluidos envolvidos (reologia) na eficiência do deslocamento. Com base nesses resultados é possível prever quais parâmetros operacionais otimizam o processo de deslocamento. / [en] In cementing processes of oil wells, the mud formerly used to drag the gravel, to lubricate and to cool the drill is removed and substituted by a cement mixture. This substitution is obtained by the displacement of a fluid by another in the annulus between the rock formation and the casing. For best results of cementing process, intermediate fluids, also called spacers, are used between the drill mud and the cement mixture. The displacement process is very complex due to geometry and fluids characteristics. The annular space is eccentric in most cases, and both drilling mud and cement mixtures are non-Newtonian fluids. In this work, an experimental and numerical study is performed to analyze this process. A vertical experimental plant was constructed to simulate the fluid displacement through eccentric annuli. The interface shapes between two adjacent fluids were visualized using a digital CCD camera. The images were compared with the results obtained in the numerical simulations. The numerical solution was obtained via the Finite Volume technique and using the Volume-of-Fluid method. The effects of eccentricity, displacement velocity and rheological parameters on the displacement e± ciency were investigated. Based on these results we can predict the liquid characteristics and the operational parameters that optimize the displacement process.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references and index.