Literatura científica selecionada sobre o tema "Thixotropy"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Consulte a lista de atuais artigos, livros, teses, anais de congressos e outras fontes científicas relevantes para o tema "Thixotropy".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Artigos de revistas sobre o assunto "Thixotropy"
1
Lakie, Martin, e Kenneth S. Campbell. "Muscle thixotropy—where are we now?" Journal of Applied Physiology 126, n.º 6 (1 de junho de 2019): 1790–99. http://dx.doi.org/10.1152/japplphysiol.00788.2018.
Texto completo da fonteResumo:
Relaxed skeletal muscle has an inbuilt resistance to movement. In particular, the resistance manifests itself as a substantial stiffness for small movements. The stiffness is impermanent, because it forms only when the muscle is stationary for some time and is reduced upon active or passive movement. Because the resistance to movement increases with time at rest and is reduced by movement, this behavior has become known as muscle thixotropy. In this short review, we describe the phenomenon of thixotropy and illustrate its significance in postural control with particular emphasis on human standing. We show how thixotropy came to be unambiguously associated with muscle mechanics and we review present knowledge of the molecular basis of thixotropic behavior. Specifically, we examine how recent knowledge about titin, and about the control of cross-bridge cycling, has impacted on the role of non-cross-bridge mechanisms and cross-bridge mechanisms in explaining thixotropy. We describe how thixotropic changes in muscle stiffness that occur during transitions from posture to movement can be tracked by analyzing physiological tremor. Finally, because skeletal muscle contains sensory receptors, and because some of these receptors are themselves thixotropic, we outline some of the consequences of muscle thixotropy for proprioception.
2
De Schryver, Robin, e Geert De Schutter. "Insights in thixotropic concrete pumping by a Poiseuille flow extension". Applied Rheology 30, n.º 1 (9 de novembro de 2020): 77–101. http://dx.doi.org/10.1515/arh-2020-0103.
Texto completo da fonteResumo:
AbstractThixotropy is a reversible time-dependent phenomenon in fluids, in which an internal structure grows due to flocculation and breaks down under shear action. Numerous fluids are thixotropic, e.g. concretes and cementitious suspensions. Pumping of concrete is an important application. Since current approaches omit thixotropic effects, we aim to develop a simple theoretical model to evaluate or understand the significance of thixotropy on the concrete pumping behaviour. We therefore extended Poiseuille flow for thixotropic concretes and reformulated it in a dimensionless form to gain insights. After a validation, the results and significance are elaborated and concluded.Results showed that for increasing thixotropy and decreasing flow rates, the plug radius, wall shear rate and pumping pressure loss increase. Even though all thixotropy mechanisms may not be covered, a simple model is delivered to interpret or predict the effect of thixotropy on the pumping behaviour of cementitious suspensions. The dimensionless formulations via the Bingham number Bn and related discharge diagrams are sufficiently elegant for computational implementation and very insightful to distinguish a thixotropic flow regime. The model could be extended for more complicated thixotropies, irreversible time-dependent effects or even other pumping related phenomena.
3
Tang, Bin, Tianli Liu e Biaohe Zhou. "Duncan–Chang E-υ Model Considering the Thixotropy of Clay in the Zhanjiang Formation". Sustainability 14, n.º 19 (27 de setembro de 2022): 12258. http://dx.doi.org/10.3390/su141912258.
Texto completo da fonteResumo:
The clays of the Zhanjiang Formation in the coastal area of Beibu Gulf of China are thixotropic, and the existing constitutive relationship models relevant for clay are incapable of accurately simulating their stress–strain relationships. It is vital to study the changes of mechanical properties of Zhanjiang Formation clay that occur during thixotropy, and to establish a constitutive model considering thixotropy. The varying measures of its shear strength, cohesion, internal friction angle, and initial tangential modulus during thixotropy were investigated by means of triaxial consolidation and drainage tests. Furthermore, the quantitative relationships between the clay’s cohesion, internal friction angle, and initial tangential modulus of the clay and time were examined. This relationship was introduced into the Duncan–Chang model, and a Duncan–Chang model considering the thixotropy of clay was developed. The established model was used to make predictions to assume the validation of the experimental data, and numerical simulations were then carried out. All of the results from the model’s prediction, numerical simulation and experimental measurements were compared against each other in order to verify the reasonableness of the model we had utilized. The results positively demonstrated that: (1) the shear strength, cohesion, angle of internal friction, and initial tangent modulus of the clay gradually increases with longer curing times, and eventually it will stabilize; and (2) compared with the Duncan–Chang model not considering thixotropy, the established thixotropic model is better able to reflect the influence of clay thixotropy on the clay stress–strain relationship, as its mean relative error is smaller. The results of this study provide references for calculating strength and deformation of the clay thixotropy. Further, it also provides references for bearing load calculations of pile foundations in thixotropic clay strata when subjected to long-term loading conditions.
4
Shao, Peng, Yu Yang Liu, Li Fen Zhou e Yu Qi Wu. "Progress in Research on Explosion Induced Thixotropy of Concrete". Materials Science Forum 675-677 (fevereiro de 2011): 643–46. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.643.
Texto completo da fonteResumo:
Thixotropy is an important property possessed by fresh concrete of changing from gel to liquid under shearing stress and returning to the original state when at rest. The thixotropic process is usually described to be an isothermal and static (or quasi-static) gel-sol-gel transformation. Now the thixotropy of concrete subjected to explosive loads became a new subject in research of synchronous explosive lining technology, which offers an advanced trechless method for underground space construction in soil. Because the detonation of explosives is a short-duration process accompanying with high temperature and high pressure, thixotropic behavior of concrete is no longer as same as that of in general meaning. This review summarizes the recent progress in research on explosion induced thixotropy of concrete, including the thixotropic behavior, thixoforming, influence of thixotropic process on microstructure, macrostructure and mechanical performances of concrete and steel fibre reinforced concrete. Additional, some arguments and suggestions for the future research are presented.
5
Gu, Ling Ya, Kai Yuan Luo, Bei Qing Huang e Yin Di Song. "Effects of Fillers on the Transfer Properties of UV Waterless Offset Ink". Applied Mechanics and Materials 262 (dezembro de 2012): 510–13. http://dx.doi.org/10.4028/www.scientific.net/amm.262.510.
Texto completo da fonteResumo:
In order to investigate the effects of fillers on the transfer properties of UV waterless offset ink, four ink samples compound with different fillers(SiO2 , CaCO3 and Talc) were prepared, the flow curve, thixotropy and ink transferred ratio were tested, and the effects of rheological properties on ink-transfer were discussed. The results show that: all of four ink samples show a typical shear thinning characteristics. Sample use SiO2 and CaCO3 as fillers has a higher viscosity, and with the increase of shearing rate, the viscosity decreased sharply. Sample use SiO2 and CaCO3 as fillers has the minimum thixotropic area, and the minimum thixotropy. Sample use SiO2 and Talc as fillers has the largest thixotropic area, and the largest thixotropy. Sample use SiO2 and CaCO3 as fillers has the highest ink transfer ratio.
6
Sen, Samya, e Randy H. Ewoldt. "Thixotropic spectra and Ashby-style charts for thixotropy". Journal of Rheology 66, n.º 5 (setembro de 2022): 1041–53. http://dx.doi.org/10.1122/8.0000446.
Texto completo da fonteResumo:
There is no universal model for thixotropy, and comparing thixotropic effects between different fluids is a subtle yet challenging problem. We introduce a generalized (model-insensitive) framework for comparing thixotropic properties based on thixotropic spectra. A superposition of exponential stress modes distributed over thixotropic time scales is used to quantify buildup and breakdown times and mode strengths in response to step-change input. This mathematical framework is tested with several experimental step-shear rate data on colloidal suspensions. Low-dimensional metrics based on moments of the distribution reveal characteristic average thixotropic properties, which are visualized on Ashby-style diagrams. This method outlines a framework for describing thixotropy across a diverse range of microstructures, supporting scientific studies as well as material selection for engineering design applications.
7
Tang, Bin, Biaohe Zhou, Liang Xie, Jianfeng Yin, Shengnan Zhao e Zhibing Wang. "Strength Recovery Model of Clay during Thixotropy". Advances in Civil Engineering 2021 (2 de fevereiro de 2021): 1–11. http://dx.doi.org/10.1155/2021/8825107.
Texto completo da fonteResumo:
Thixotropy is a hot topic in the field of rheology of dispersed systems. Many researchers have proposed different models and hypotheses to explain the thixotropy of clay. In this paper, the strength recovery model of Zhanjiang Formation clay in the process of thixotropy is studied. Firstly, through unconfined compressive strength test, the influence of soil sensitivity, moisture content, and density on the strength growth of remolded soil was studied. The results show great influence of sensitivity, moisture content, and density on the thixotropic strength of the Zhanjiang Formation clay: the higher the sensitivity and the density, the stronger the thixotropy of soil; the higher the moisture content, the weaker the thixotropy of soil. Based on the test results, a strength recovery model of Zhanjiang Formation clay in the process of thixotropy was established. The model was verified by the validation test data and the data obtained from the existing literature. The results suggest that the model prediction is in good agreement with the verification test data and data from existing literature, which proves the confidence of the model in predicting the degree of strength recovery in the process of thixotropy of Zhanjiang Formation clay. The model provides basis for stability calculation of surrounding soil after construction disturbance of underground structures in this stratum.
8
Yang, Xu, Wen Chen, Rui Xiao e Leevan Ling. "A fractional model for time-variant non-Newtonian flow". Thermal Science 21, n.º 1 Part A (2017): 61–68. http://dx.doi.org/10.2298/tsci160426245y.
Texto completo da fonteResumo:
This work applies a fractional flow model to describe a time-variant behavior of non-Newtonian substances. Specifically, we model the physical mechanism underlying the thixotropic and anti-thixotropic phenomena of non-Newtonian flow. This study investigates the behaviors of cellulose suspensions and SMS pastes under constant shear rate. The results imply that the presented model with only two parameters is adequate to fit experimental data. Moreover, the parameter of fractional order is an appropriate index to characterize the state of given substances. Its value indicates the extent of thixotropy and anti-thixotropy with positive and negative order respectively.
9
Nicia, David, Nicholas Fobbe, Daniel Jansen e Dirk Lowke. "Rheology of low‐clinker suspensions: Multiscale comparison of the effect of PCE on thixotropy". ce/papers 6, n.º 6 (dezembro de 2023): 705–14. http://dx.doi.org/10.1002/cepa.2811.
Texto completo da fonteResumo:
AbstractAddressing climate change requires reducing the carbon footprint of cement‐based building materials on a global scale. One promosing approach involves decreasing the clinker content by incorporating fine supplementary cementitious materials (SCM), which, however, can increase the stickiness of fresh concrete. Along with viscosity, thixotropic structural build‐up is a critical rheological parameter that impacts the stickiness of the SCM‐rich suspensions. Thus, it is essential to gain a precise understanding of how the molecular structure and mode of addition of polycarboxylate ethers (PCE) affect the thixotropic structural build‐up in low‐clinker suspensions. To address this issue, we investigate key parameters affecting thixotropy, specifically PCE adsorption and early hydration kinetics at the cement paste and mortar level, using a multiscale approach. In an application‐oriented concept, we maintain a constant yield stress by varying the PCE dosage to achieve constant workability. Our results demonstrate that higher thixotropy correlates with increased PCE charge density and direct addition in cement pastes and mortars. Moreover, it is indicated that increasing specific surface area and ettringite contents promote additional thixotropy‐enhancing mechanisms.
10
Ma, Xiaoyan, Yubo Wang, Junpeng Hou, Yanping Sheng, Wanpeng Zheng e Shujuan Wu. "Study on Thixotropic Properties of Asphalt Mastics Based on Energy Viewpoint". Coatings 13, n.º 3 (20 de março de 2023): 650. http://dx.doi.org/10.3390/coatings13030650.
Texto completo da fonteResumo:
An asphalt mastic has thixotropic characteristics that significantly influence its fatigue and healing performance. Therefore, understanding the thixotropy of an asphalt mastic is clearly of great importance. However, research in this area is still in the early stages. This study focuses on self-heating as one of the biasing performances of asphalt material by analyzing the viscosity, stress, and hysteresis loops the of asphalt mastics under cyclic shear loading. Twelve types of asphalt mastics fabricated with asphalt, as well as different types of mineral filler, were selected to examine thixotropy. In addition, the filler/asphalt ratio was examined via the hysteresis technique to analyze the hysteresis loop and the viscosity–shear rate. The thixotropic potential function was also studied from the energy viewpoint. The results show that asphalt mastics with different asphalt binders, mineral fillers, and filler volume fractions showed hysteresis loops for shear stress versus shear rate diagrams. With an increase in the loading times of the cyclic load, the area of the hysteresis loop gradually decreases, and the hysteresis area most likely features a relatively stable value. The thixotropy of the asphalt can be significantly reduced by adding filler, and different types of mineral filler can slightly influence the thixotropy. The viscosity decreases with an increase in the shear rate, and it gradually recovers with a decrease in the shear rate. The greater the filler/asphalt ratio, the greater the viscosity, and the faster the viscosity’s descent is with the prolongation of time. Due to the existence of a higher amount of filler content, the recovery of a viscosity crack is more difficult. For asphalt mastics with high filler/asphalt ratios, the thixotropic mechanism can be explained via particle agglomeration and the depolymerization theory. For asphalt mastics with low and medium filler/asphalt ratios, the thixotropic mechanism can be explained via the particle chain theory. The damage and recovery of the internal structure of an asphalt mastic can be characterized by the structural failure potential function and the structural recovery potential function, respectively.
Teses / dissertações sobre o assunto "Thixotropy"
1
Axelson, Hans. "Muscle Thixotropy : Implications for Human Motor Control". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5791.
Texto completo da fonte
2
Anvari, Ardakani Hesam. "Rheology of pastes : effects of fibrillation, thixotropy and structure". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46979.
Texto completo da fonteResumo:
Three different pastes (toothpaste, PTFE paste that is mixture of polytetrafluoroethylene of submicron size particles with a liquid lubricant, and chocolate) are investigated in this thesis as model paste systems to study their processing characteristics in capillary flow using various dies. The rheological behaviour of toothpaste and melt chocolate paste is identified as that of a yield-stress, thixotropic material with a time-dependent behaviour. The rheological data obtained from a parallel-disk were used to formulate a constitutive equation with a structural parameter which obeys a kinetic equation, typically used to model thixotropy. For semi-solid paste extrusion (PTFE paste and solid chocolate), a simple phenomenological mathematical model is developed. The model takes into account the elastic-plastic (strain hardening) and viscous nature of the material in its non-melt state. In addition, it takes into account the slip boundary condition at the paste/wall interface. To study scale-up possibilities, the rheology of non-melt processible polytetrafluoroethylene (PTFE) pastes is studied using three capillary rheometers having barrels of different diameter and equipped with capillary dies of various designs. The effects of process conditions on fibrillation and mechanical properties of polytetrafluoroethylene (PTFE) paste extrudates are also studied. To describe the effects of die design on the quality of the final product, a basic phenomenological mathematical model is developed. The model consists of a simple equation that explains fibril formation, due to the compression of PTFE resins, plus a kinetic equation, which is coupled with the “radial-flow” hypothesis to predict the structure and the tensile strength of extrudates. Model predictions for structural parameter compared with the tensile strength measurements, have shown a good qualitative agreement. For all paste systems, the pressure drop is measured as a function of apparent shear rate (flow rate), reduction ratio (cross sectional area of barrel to that of die), contraction angle, length-to-diameter ratio, and diameter of the barrel (scale-up). In all cases, model shown to have coefficient of determination (R2) above 0.84. Finally, extrusion pressure predictions based on the proposed models are compared with the experimental data obtained from macroscopic pressure drop measurements and are found to be consistent.
3
Assaad, Joseph. "Formwork pressure of self-consolidating concrete : influence of thixotropy = Pressions latérales développées par les bétons autoplaçants contre les coffrages : influence de la thixotropie". Thèse, Université de Sherbrooke, 2004. http://savoirs.usherbrooke.ca/handle/11143/1756.
Texto completo da fonteResumo:
Recently, a new generation of concrete referred to as self-consolidating concrete (SCC) appeared on the market. This kind of concrete is characterized by its high fluidity and resistance to segregation. It enables the elimination of the vibration during the casting process and reduces the need for manpower on the construction site. The use of SCC has gained increased acceptance and it became essential to better understand the lateral pressure that can be developed on the vertical formwork systems. Presently, formworks are designed prudently by assuming that the plastic concrete exerts full hydrostatic pressure until the setting time. Such pressure is expressed as: P[subscript max] = p × g × H where p, g, and H correspond to the concrete unit weight, gravity, and head of concrete, respectively. Such approach can result in increased construction costs and can limit the rate of rise of the concrete in the formwork. An experimental program was undertaken in the University of Sherbrooke to evaluate the lateral pressure developed by SCC mixtures. A special emphasis was placed on the influence of concrete thixotropy on the pressure development. Various mixture parameters, including the coarse aggregate characteristics, binder type and content, as well as the water-to-binder ratio were investigated. The effect of incorporating chemical admixtures such as the set-modifying and water-reducing agents, high-range water-reducing and viscosity-modifying admixtures (HRWRA and VMA, respectively) were evaluated. The effect of consistency level, concrete temperature, and casting rate on formwork pressure were also determined. Test results showed that the variations in lateral pressure of SCC are highly affected by the development of shear strength properties, namely the internal friction and cohesion. The higher the degree of internal friction, the lower is the maximum initial pressure measured right after the end of casting. Increased degree of internal friction can be ensured by incorporating a greater volume of coarse aggregate. This can also be achieved indirectly by proportioning mixtures with lower binder contents and/or water-to-binder ratios."--Résumé abrégé par UMI.
4
Thiene, Oumar. "Rhéologie des boues résiduaires : rôle de la thixotropie et de la composition sur les propriétés liquides et solides". Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC033/document.
Texto completo da fonteResumo:
Alors que la quantité de boues résiduaires produites à l’échelle mondiale ne cesse d’augmenter, la gestion de ces boues est désormais devenue un enjeu sociétal majeur. Dans le cadre d’une politique de développement durable, son efficacité passe nécessairement par la réduction des volumes produits (via l’optimisation des procédés de traitement) et par une meilleure valorisation. Pour cela, les procédés ainsi que les outils mis en oeuvre pour traiter puis valoriser le matériau doivent être de plus en plus performants. Les traitements étant essentiellement basés sur des écoulements, cette performance accrue nécessite la mesure et la maîtrise des caractéristiques des boues résiduaires telles que la consistance et les propriétés d’écoulement. Cependant le matériau est complexe et ses propriétés rhéologiques varient selon sa composition. Ainsi, le principal critère utilisé pour déterminer sa consistance, la teneur en matière solide, s’avère limité puisque la boue la plus consistante n’est pas nécessairement celle qui contient le plus de matière solide. Un état de l’art sur le comportement rhéologique des matériaux non-Newtoniens en général et des boues résiduaires en particulier a montré l’intérêt de s’intéresser au rôle de la matière organique et de la thixotropie dans la variabilité des propriétés rhéologiques du matériau. Dans cet objectif, une méthodologie expérimentale a d’abord été développée pour s’assurer de l’obtention de résultats fiables. Cela a permis de montrer l’influence des procédures expérimentales sur les mesures rhéologiques et de définir une procédure expérimentale robuste garantissant la répétabilité et la reproductibilité des résultats obtenus. Puis, à partir de cette procédure expérimentale, il a été montré que les effets de la thixotropie n’affectent que les propriétés solides des boues, les propriétés liquides en étant indépendantes. De plus, cette approche a permis de mettre en évidence que le comportement thixotrope est intrinsèquement lié à la matière organique contenue dans les boues : plus la matière organique est élevée, plus les boues sont thixotropes. Ensuite, à partir de la matière solide et de la proportion de matière organique contenue dans le solide, un critère plus pertinent que la teneur en matière solide a été établi pour comparer les propriétés rhéologiques entre boues d’origines différentes. Ce critère, appelé consistance équivalente, s’avère suffisant pour tenir compte de l’influence de la composition sur les propriétés rhéologiques des boues. Enfin, selon la valeur de la consistance équivalente, il a été montré que le comportement rhéologique des boues résiduaires peut être considéré comme Newtonien, non-Newtonien simple (effets thixotropes négligeables) ou non-Newtonien avec des effets thixotropesSludge management is a major issue as the production is increasing year after year while the solutions to reuse it are limited. In the context of sustainable management and circular economy, treatment processes need to be well controlled to pilot operating systems. Since treatment processes are essentially based on flowing properties, improving the efficiency requires the measurement and control of sludge rheology, among which viscous properties. However, sludge is complex material and its rheological properties highly dependent of its composition. The solid content, the most usual parameter considered to evaluate rheological properties, is quite limited as sludge consistency is not directly connected to the solid content. An in-depth state of the art review on non-Newtonian materials rheology with a focus on sewage sludge has underlined the role of organic matter and thixotropy in complex fluid rheological properties. In that purpose, an experimental methodology was defined to ensure reliable results. This allowed to highlight the impact of experimental setups on rheological measurements and to define a robust experimental methodology that ensures the repeatability and the reproducibility of the measurements. Then, thanks to this experimental methodology, it has been shown that thixotropy is a solid-like characteristic, viscous properties being independent of material history. In addition, this approach has made it possible to demonstrate that the thixotropic behavior is intrinsically connected to the organic matter content: the higher the organic matter, the more thixotropic the sludge. Moreover, from the solid matter and the ratio of organic matter in the solid, a criterion (more relevant than the solid content) has been established to compare the rheological properties between sludge of different origins. This criterion, called equivalent consistency, appears to be sufficient to take into account the impact of the composition on sludge rheological properties. Finally, it has been shown that the rheological behavior of sewage sludge can be considered as Newtonian, simple non-Newtonian (with negligible thixotropic effects) or non-Newtonian with thixotropic effects depending the value of the equivalent consistency
5
MOISÉS, GUSTAVO VINICIUS LOURENÇO. "EFFECTS OF YIELD STRESS AND THIXOTROPY IN NON-NEWTONIAN ISODENSE DISPLACEMENT". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=27820@1.
Texto completo da fonteResumo:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
O aparecimento de tensão limite decorrente da gelificação de óleo parafínicos constitui um problema significativo em linhas submarinas nos sistemas de produção de petróleo em água profundas. Essencialmente, existem dois modos para garantir retorno da produção em oleodutos após longas paradas: aplicar um elevado diferencial de pressão suficiente para mover o gel no duto, reinício de produção, ou injetar um fluido misccível de baixa viscosidade, preferencialmente Newtoniano, na entrada do duto, processo denominado deslocamento de fluido. Nós investigamos os efeitos da tensão limite e da tixotropia no escoamento de fluidos não Newtonianos em dutos horizontais, considerando tanto o reinício de produção quanto o deslocamento de fluidos sem diferença de densidade. Tanto a tensão limite como as propriedades tixotrópicas dos óleos parafínicos foram simuladas reologicamente por fluidos base água, soluções de Carbopol e suspensões de Laponita. Os resultados experimentais e os estudos numéricos do deslocamento de fluidos com tensão limite sem diferença de densidade são apresentados. Três tipos distintos de escoamento, que pertencem a categoria deslocamento central, foram identificados nos experimentos e chamados de corrugado, ondulado e liso a depender do nível de variação da camada residual ao longo do duto. A transição entre esses regimes foi identificada como da razão entre a tensão inercial e a tensão característica do fluido viscoplástico. Além disso, a influência das concentrações de NaCl e Laponita nos parâmetros reológicos das suspensões de Laponita é detalhada e o impacto da tixotropia no reinício de produção de suspensões de Laponita foi analisada com base em dados experimentais.
The yield stress appearance when gelation occurs in wax crude oils constitutes a significant problem in subsea flowline in deepwater oil production systems. In essence, there exist two stages in a pipeline flow restart after a long shutdown: apply a large enough differential pressure in order to mobilize the gel in the pipe, i.e. a process of fluid start-up or inject miscible fluid with low viscosity, preferably Newtonian, at the pipe inlet, to flush the gelled oil out of the pipe, i.e. a process of fluid displacement. We investigate yield stress and thixotropy effects over non-Newtonian fluid flows in a horizontal pipe, considering the fluid start- up and the fluid displacement in the isodense limit. The yield stress and thixotropic properties of waxy crude oils are rheologicaly simulated by water base fluids, Carbopol solutions and Laponite suspensions. The results of experimental and numerical studies of isodense displacement of a yield stress fluid are presented. Three distinct flow types belonging to this central displacement are identified in the experiments namely corrugated, wavy and smooth depending on the level of the residual layer variation along the pipe. The transition between these flow regimes is found to be a function of the ratio between the inertial stress and the characteristic viscous stress of the viscoplastic fluid. Besides, the influence of NaCl and Laponite concentrations in the rheological parameters of Laponite suspensions is detailed and the impact of thixotropy in the start-up of Laponite suspensions are analyzed based on experimental results.
6
Seffern, Pascal. "Beitrag zur Identifizierung rheologischer Wechselwirkungen von Kaolinen in wässrigen Systemen". Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2018. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-232052.
Texto completo da fonteResumo:
The present dissertation investigates the flow behavior of concentrated Kaolin slurries and furthermore novel rheological measurement-, analysis-, and assessment procedures for characterizing static and dynamic flow behavior in industrial and research applica- tions. Ten different Kaolins with divergent property profiles were investigated in detail. At first, novel measurement and analysis procedures are presented and the raw material inherent properties are correlated with the resulting flow characteristics. The results describe the structural building and breakdown (in both static and dynamic states) of concentrated Kaolin slurry suspensions with and without deflocculant and also the determination of the point of optimal deflocculant concentration through the develop- ment of a novel analysis method and linking of the parameters to a condition matrix. The results lead to a better understanding of the flow behavior of concentrated Kaolin slurries. Due to the use of a strict measurement protocol with a focus on the elimination of external disturbances on the determination of flow behavior, the phases of dynamic structure construction and destruction (with exclusion of temporal structure effects and vice versa) can be analyzed. It was identified that the construction of particle networks requires less energy than their destruction. Furthermore it could be demonstrated that the occurrence of a transient shear stress peak in kaolin slurries is the cause for the breakdown of an existing particle network and not, as conventionally reported, due to an insufficient measurement time. Moreover, through the combination and modification of two measurement protocols described here, manufacturing companies have a potentially useful tool for composition development and quality control without the necessity of purchasing a highly precise research rheometerIn der vorliegenden Arbeit wird das Fließverhalten von konzentrierten Kaolinsuspensio- nen untersucht und neuartige rheologische Mess-, Analyse- und Bewertungsverfahren zur Charakterisierung der Belastungs- und Zeitabhängigkeit für Industrie- und Forschungsanwendungen vorgestellt. Hierzu wurden zehn Kaoline mit divergierenden Eigenschaftsprofilen untersucht. Zunächst werden neuartige Mess- und Analyseverfahren vorgestellt und die Eigenschaften der Rohstoffe mit den ermittelten Fließcharakteristika korreliert. Die Ergebnisse beschreiben den strukturellen Auf- und Abbau (zeit- und belastungsabhängig) von konzentrierten Kaolinsuspensionen mit und ohne Dispergierhilfsmitteleinsatz und darüber hinaus die Ermittlung der optimalen Dispergierhilfsmittelkonzentration durch Entwicklung einer neuartigen Analyse und Verknüpfung von Parametern an eine Bedingungsmatrix. Die Erkenntnisse tragen zum besseren Verständnis des Fließverhaltens konzentrierter Kaolinsuspensionen bei. Aufgrund der entwickelten Messvorschriften und der darin elementar verankerten Elimination von Störgrößen auf die Ermittlung des Fließverhaltens konnten die Phasen des strukturellen Auf- und Abbaus unter Belastung (unter Ausschluss von temporalen Struktureffekten und umgekehrt) analysiert werden. Es wurde festgestellt, dass die Konstruktion von Partikelnetzwerken weniger Energie benötigt, als deren Destruktion und das Auftreten des Schubspannungshügels auf den Zusammenbruch des Partikelnetzwerkes und nicht, wie allgemein beschrieben auf zu geringe Messzeiten zurück zu führen ist. Darüber hinaus wird der produzierenden Industrie, durch Abwandlung und Kombination zweier Messvorschriften ein Werkzeug zur Versatzentwicklung und Qualitätskontrolle, auch ohne die Notwendigkeit des Erwerbs von hochpräzisen Forschungsrheometern bereitgestellt
7
Dimitriou, Christopher (Christopher J. ). "The rheological complexity of waxy crude oils : yielding, thixotropy and shear heterogeneities". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81696.
Texto completo da fonteResumo:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 305-320).
Precipitate-containing crude oils are of increasing economic importance, due to diminishing oil reserves and the increased need to extract hydrate and wax-containing crude oil from ultra deep-water resources. Despite this need, the rheological behavior of these types of crude oil is often poorly understood. In this thesis, we investigate some of the underlying complexities associated with the rheology of waxy crude oils. These complex phenomena are often difficult to both quantify experimentally and capture with existing constitutive models. The contribution of this thesis is therefore to develop a detailed understanding of three of these particular phenomena, through the development and use of several new experimental and theoretical tools. A better understanding of waxy crude oil rheology is critical for developing flow assurance strategies, which can in turn ensure continuous production of precipitate-containing crude oils under adverse conditions. The three phenomena studied are, first: shear heterogeneities, i.e. the manifestation of wall slip, shear banding or other shear-localization events under imposed deformations that are assumed to be homogenous. For these purposes, flow visualization techniques capable of "Rheo-PIV" measurements are developed to detect these heterogeneities. Second: elasto-viscoplasticity, or the presence of an elastic response and a yield-like behavior in a non-Newtonian fluid. Constitutive modeling of this type of behavior is difficult to achieve using standard linear viscoelastic techniques, where the viscoelastic response is decomposed into a finite number of linear elements with a spectrum of relaxation times. For these reasons, additional concepts are adopted from plasticity models in order to describe this behavior. Finally: thixotropy, which refers to the ability of a fluid to continuously evolve, or age at rest and shear rejuvenate under a constant applied shear rate. A rigorous set of experimental tests is constructed which allow for the appropriate constitutive model parameters to be determined for a thixotropic fluid. Through quantitative study of these phenomena, we reach several conclusions about how to characterize and model the rheology of a precipitate-containing crude oil. First, measurements of shear heterogeneities are important in these fluids, so that rheological characterization may proceed with a knowledge of when these may arise and introduce artifacts into data. Second, new nonlinear rheometric techniques are necessary to develop quantitative data sets that describe the inherently nonlinear rheology of these fluids. The specific technique developed in this work is termed stress-controlled large amplitude oscillatory shear, or LAOStress. Finally, we show that the constitutive behavior of these materials is best prescribed using a framework which utilizes yielding and hardening mechanisms from plasticity theory. The resulting constitutive model for this nonlinear elasto-viscoplastic and thixotropic class of materials is expressed in a closed form that can be used in existing flow assurance simulation tools. The most relevant applications for this work are in the flow assurance challenges associated with crude oil production. Consequently, a large portion of the experimental work is carried out on a model waxy crude oil, containing a total wax content ranging from 5 to 10% by weight. However the phenomena studied here occur ubiquitously in a number of complex fluids. For this reason, the same rheological complexities are studied in the context of several other fluids, including a swollen microgel paste (Carbopol) and a shear-banding wormlike micellar solution.
by Christopher J. Dimitriou.
Ph.D.
8
Whitehead, Nicholas P. (Nicholas Paul) 1975. "Factors affecting the passive mechanical properties of skeletal muscle : thixotropy and eccentric contractions". Monash University, Dept. of Physiology, 2002. http://arrow.monash.edu.au/hdl/1959.1/7883.
Texto completo da fonte
9
Umerova, S. O., I. O. Dulina e A. V. Ragulya. "Rheology and Printability of Pastes Based on BaTiO3 Nanopowder Depending on Ethyl Cellulose Viscosity". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42513.
Texto completo da fonteResumo:
This paper is about rheology of pastes based on BaTiO3 nanopowder with ethyl cellulose 100 cP (paste P1) and 10 cP (paste P2) as organic binder. It was established, that P1 was pseudoplastic – thixotropic system and P2 was rheopexic - pseudoplastic – thixotropic one. The reduction of EC viscosity led to changing of paste structurization type from pseudoplastic (P1) to plastic one (P2). Structurization of P1 can be explained with excess of polymer in the paste composition and with dominance of the polymer – polymer bonds. Unlike P1, P2 has some elastic properties due to strong structural links because of polymer – nanoparticle bonds. Moreover, the value of initial viscosity
of P2 (2.11 Pa∙s) was much less than of P1 (37,5 Pa∙s). It was found, that the viscosity of polymer influences the paste printability. In particular, P2 was more prone to form thinner and smoother prints. Thus, composition of P2 was more promising one for obtaining prints with good quality and subsequent assembly into a multilayer object due to its elastic properties during low deformation.
10
Liard, Maxime. "Suspension concentrées : systèmes non newtoniens et thixotropie sous écoulement". Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE039/document.
Texto completo da fonteResumo:
Cette thèse de doctorat a été financée par l’entreprise SIKA spécialisée dans les matériaux de construction. Les trois chapitres de cette thèse correspondent à la tentative de résolution de trois problématiques d’origine industrielle. Dans le premier chapitre, nous avons étudié l’effet de la concentration en particules sur les propriétés d’écoulement de fluides complexes rhéofluidifiants ou rhéoépaississants et démontré l’origine microscopique de cet effet. Dans le second chapitre, nous avons étudié la floculation de particules colloïdales sous faibles perturbations et mis en évidence l’existence, au cours de la reconstruction, d’un maximum du module élastique. Enfin le troisième chapitre est l’étude d’un diagramme de phase de jet de suspensions concentrées. En régime dilué et semi-dilué, les résultats sont conformes à ceux de la bibliographie, en revanche nous avons étudié un nouveau régime à très haute fraction volumique où le jet, instable, se met à osciller. Nous avons montré que ces oscillations étaient dues au rhéoépaississement de la suspensionThis thesis has been done in collaboration with the company SIKA, one of the leader if the construction industry. This thesis report is organized in three chapters where each of them tries to answer a problem coming from industrial processes. In the first chapter, we studied the impact of particles concentration on the flowing properties of complex fluids such as shear-thinning and shear-thickening fluids. We demonstrated the importance of local contacts between particles to explain the evolution of the viscosity with the volume fraction. In the second chapter, we studied the aggregation of colloidal attractive suspensions under small perturbations and proved the existence of a maximum of elastic modulus during the rebuilding of the structure. Finally, the third chapter is a study of a phase diagram of a concentrated suspension jets. In the diluted and semi-diluted regimes, we found results in agreement with the bibliography, meanwhile at very high concentration, we studied a new regime where the jet, unstable, is oscillating. We showed those oscillations can be explained by the shear-thickening behaviour of the suspensions at those high concentrations
Livros sobre o assunto "Thixotropy"
1
Characterization of structural rebuilding and shear migration in cementitious materials in consideration of thixotropy. [New York, N.Y.?]: [publisher not identified], 2017.
Encontre o texto completo da fonte
2
Idris, Azmi. Non-contact ultrasonic study on thixotropic alloys. [s.l.]: typescript, 1995.
Encontre o texto completo da fonte
3
Thixotropy. Valiz, 2009.
Encontre o texto completo da fonte
4
Chung, Deborah Duen Ling. Thixotropic Liquid-Metal-based Fluid and Its Use in Making Metal-based Structures with or Without a Mold: United States Patent 9993996. Independently Published, 2020.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Thixotropy"
1
Gooch, Jan W. "Thixotropy". In Encyclopedic Dictionary of Polymers, 748. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_11844.
Texto completo da fonte
2
Lutenegger, Alan J. "Thixotropy". In Laboratory Manual for Geotechnical Characterization of Fine-Grained Soils, 295–304. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003263289-27.
Texto completo da fonte
3
Chesworth, Ward, Otto Spaargaren, Amos Hadas, Pieter H. Groenevelt, Xosé L. Otero, T. O. Ferreira, P. Vidal, F. Macías, W. Chesworth e Charles W. Finkl. "Thixotropy, Thixotropism". In Encyclopedia of Soil Science, 781–82. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-3995-9_598.
Texto completo da fonte
4
Godfrey, J. C., e M. F. Edwards. "A Power-Law Model of Thixotropy". In Third European Rheology Conference and Golden Jubilee Meeting of the British Society of Rheology, 183–85. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0781-2_67.
Texto completo da fonte
5
Thiedeitz, Mareike, Thomas Kränkel e Christoph Gehlen. "Thixotropy-Dependent Form Filling Ability of Cement Paste". In RILEM Bookseries, 273–80. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22566-7_32.
Texto completo da fonte
6
Vandenberg, Aileen, Hela Bessaies-Bey, Kay Wille e Nicolas Roussel. "Enhancing Printable Concrete Thixotropy by High Shear Mixing". In RILEM Bookseries, 94–101. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-99519-9_9.
Texto completo da fonte
7
Cocard, S., e J. F. Tassin. "Rheo-Optical Study of Thixotropy in Synthetic Clay Suspensions". In Progress and Trends in Rheology V, 545–46. Heidelberg: Steinkopff, 1998. http://dx.doi.org/10.1007/978-3-642-51062-5_265.
Texto completo da fonte
8
Gillings, David. "Herbert Freundlich and Thixotropy the Long Horizon of His Pioneering Insight". In Third European Rheology Conference and Golden Jubilee Meeting of the British Society of Rheology, 180–82. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0781-2_66.
Texto completo da fonte
9
De Schryver, Robin, Khadija El Cheikh, Mert Y. Yardimci, Karel Lesage e Geert De Schutter. "Fresh Concrete Pumping Arrest Investigation for Thixotropy by a CFD Modelling Approach". In RILEM Bookseries, 580–87. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22566-7_67.
Texto completo da fonte
10
Hagbarth, K. E., J. V. Hägglund, M. Nordin e E. U. Wallin. "Muscle Thixotropy and Its Effect on Spindle and Reflex Responses to Stretch". In Advances in Applied Neurological Sciences, 91–97. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71540-2_11.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Thixotropy"
1
Cayeux, Eric, e Amare Leulseged. "Modelling of Drilling Fluid Thixotropy". In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77203.
Texto completo da fonteResumo:
Drilling fluids are visco-elastic materials, i.e. they behave as a viscous fluid when subject to a sufficient shear stress and like an elastic solid otherwise. Both their elastic and viscous properties are time-dependent, i.e. drilling fluids are thixotropic. Because of thixotropy, it takes a finite time before the effective viscosity of a drilling fluid attains an equilibrium when the fluid is subject to a change of shear rate. This effect is visible when one changes the applied shear rate in a rheometer, as the fluid will gradually adapt to the new shearing conditions. When the velocity of a drilling fluid changes, for instance due to a change in pump flow rate, movement of the drill string, or change of flow geometry, the fluid will exhibit a time-dependent response to the new shearing conditions, requiring a certain time to reach the new equilibrium condition. Unfortunately, the time-dependence of the rheological properties of drilling fluids are usually not measured during drilling operations and therefore it is difficult to estimate how thixotropy impacts pressure losses in drilling operations. For that reason, we have systematically measured the time-dependence of the rheological properties of several samples of water-based, oil-based and micronized drilling fluids with a scientific rheometer in order to capture how drilling fluids systems respond to variations of shear rates. Based on these measurements, we propose to investigate how one existing thixotropic model manages to predict the shear stress as a function of the shear rate while accounting for the shear history and gelling conditions. Then we propose a modified model that fits better, overall, with the measurements even though there are still noticeable discrepancies, especially when switching back to low shear rates.
2
Lee, John, Ahmadi Tehrani, Steve Young e Christine Nguyen. "Viscoelasticity and Drilling Fluid Performance". In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23908.
Texto completo da fonteResumo:
Viscoelastic properties of drilling fluids are not often measured due to a lack of understanding of their impact on fluid performance as well as a lack of field equipment suitable for such measurements. A study has been conducted recently to evaluate the viscoelastic properties of xanthan gum and invert drilling fluids and their impact on barite suspension quality and rheology. Both a Brookfield YR-1 rheometer and a Bohlin Gemini 150 rheometer were used to generate data for comparison. The impact of viscoelasticity on steady-state rheology, thixotropy and shear thinning was evaluated using a multi-speed rheometer. A soon-to-be-adopted API recommended procedure was used to measure the barite sag tendency under dynamic conditions. Aqueous solutions of xanthan gum showed that viscoelasticity, shear thinning and thixotropy increased with increasing polymer concentration. When the solutions were weighed up with barite, they became more viscoelastic, slightly more thixotropic, but less shear thinning. Proper suspension of barite was observed at a xanthan gum concentration of 2 lb/bbl without any other additives. Compared to xanthan-barite suspensions, invert drilling fluids of similar density exhibited a greater viscoelasticity but less thixotropy and shear thinning. Treatment of invert drilling fluids with viscoelastic polymers resulted in a further enhancement of viscoelasticity and thixotropy, but a slight deterioration in shear thinning. Barite suspension quality showed a certain degree of correlation with viscoelasticity as well as steady-state rheology; however, these properties were temperature dependent for invert drilling fluids. Hydraulic analyses indicated that viscoelastic additives can impact fluid viscosity thus affecting pressure loss, equivalent circulating density and hole cleaning. Viscoelasticity enhancement may be used to improve barite suspension quality under certain conditions, but its impact on hydraulics must be carefully considered.
3
Sen, Samya, e Randy H. Ewoldt. "Video: Stick or Splash? Thixotropy Decides!" In 71th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2018. http://dx.doi.org/10.1103/aps.dfd.2018.gfm.v0036.
Texto completo da fonte
4
Sanchez Perez, Carlos Eduardo, Danmer Maza e Marcio CARVALHO. "Effect of Thixotropy in Complex Flows". In 19th Brazilian Congress of Thermal Sciences and Engineering. ABCM, 2022. http://dx.doi.org/10.26678/abcm.encit2022.cit22-0112.
Texto completo da fonte
5
Ouazzi, Abderrahim, Naheed Begum e Stefan Turek. "Monolithic Finite Element Method for the simulation of thixo-viscoplastic flows". In VI ECCOMAS Young Investigators Conference. València: Editorial Universitat Politècnica de València, 2021. http://dx.doi.org/10.4995/yic2021.2021.12250.
Texto completo da fonteResumo:
This talk is concerned with the application of Finite Element Method (FEM) and Newton-Multigrid solver to simulate thixotropic flows.The thixotropy phenomena are introduced to yield stress material by taking into consideration the internal material micro structure using a structure parameter. Firstly, the viscoplastic stress is modified to include the thixotropic stress dependent on the structure parameter. Secondly, an evolution equation for the structure parameter is introduced to induce the time-dependent processof competition between the destruction (breakdown) and the construction (buildup) inhabited in the material. Substantially, this is done simply by introducing a structure-parameter-dependentviscosity into the rheological model for yield stress material, as for instance the Houska model based on a viscosity approach for the Bingham model [2].The modified viscoplastic stress w.r.t. the structure parameter which is integrated, in quasi-Newtonian manner or lagrangian multiplier manner, into the generalized Navier-Stokes equations and the evolution equation for the structure parameter constitutes the main core of full set of mod-eling equations, which are creditable as the privilege answer to incorporate thixotropy phenomena.The nonlinearity of the problem, related to the dependency of the diffusive stress on the material parameters, is treated with generalized Newton’s method w.r.t. the Jacobian’s singularities having a global convergence property. The linearized systems inside the outer Newton loops are solvedusing the geometrical multigrid methods with a Vanka-like smoother taking into account a stable FEM approximation pair for velocity and pressure with discontinuous pressure and biquadratic velocity spaces.We analyze the accuracy, robustness and efficiency of the Newton-Multigrid FEM solver [1] throughout the solution of thixotropic flow problems of benchmarking character in channel and Couette device [3].
6
Shinomiya, Keisuke, Naoya Saiki, Yousuke Sato, Manabu Miyawaki, Tomotaka Morishita e Reina Kainuma. "Precise thixotropy controlled Bump Support Film for WLCSP". In 2021 IEEE CPMT Symposium Japan (ICSJ). IEEE, 2021. http://dx.doi.org/10.1109/icsj52620.2021.9648869.
Texto completo da fonte
7
Liu, Xiang, Roger Lu, Guangchao Xie e Haiyong Gu. "Improving Moldability by Regulating Thixotropy of Epoxy Molding Compounds". In 2023 24th International Conference on Electronic Packaging Technology (ICEPT). IEEE, 2023. http://dx.doi.org/10.1109/icept59018.2023.10491915.
Texto completo da fonte
8
Feys, Dimitri, Ronny Verhoeven, Geert De Schutter, Albert Co, Gary L. Leal, Ralph H. Colby e A. Jeffrey Giacomin. "Influence of Thixotropy on Pressures Required during Pumping of Concrete". In THE XV INTERNATIONAL CONGRESS ON RHEOLOGY: The Society of Rheology 80th Annual Meeting. AIP, 2008. http://dx.doi.org/10.1063/1.2964819.
Texto completo da fonte
9
Tsugawa, Juliana K., Kelly F. S. Pereira e Maria E. G. Boscov. "Thixotropy of Sludge from the Cubatão Water Treatment Plant, Brazil". In Geotechnical Frontiers 2017. Reston, VA: American Society of Civil Engineers, 2017. http://dx.doi.org/10.1061/9780784480472.090.
Texto completo da fonte
10
Toro, Carlos, Eliana Velasquez, John Avellaneda, Luis Carlos Olivella e Edgar Luna. "Successful Application of Multipurpose Thixotropic Technology for Lost Circulation, Wellbore Strengthening through Directional Tools in Well Control Events in Colombia". In SPE Annual Technical Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/214790-ms.
Texto completo da fonteResumo:
Abstract Controlling lost circulation in formations that simultaneously present a narrow pore and fracture gradients window is one of the most complex situations to manage while drilling. High HSE risk generated by well control operational impacts profit by the non-productive days due to drilling equipment malfunction, quantity, and type of fluid loss, as well as potential directional tools lost in the hole when pipe should be cut down due to the impossibility of bringing the drill string to the surface and assure the well. All the risks could generate a not viable project. At the present day, the greatest difficulty for controlling lost circulation through directional tools is the limited availability of technologies and limited loss circulation material (LCM) concentration range that could be pumped through the motor and the Measurement or Logging While Drilling (MWD/LWD) with the required concentrations to efficiently sealed the formation. This limitation is associated with the high risk of plugging the downhole tools, which would cause a more complicated operational situation such as the inability to manage loss and well-control situations with catastrophic HSE events. Traditional lost circulation technologies are granular in nature and require large amounts of solids with a coarse size that exceeds the allowable pumped capability of the tools, or even technologies such as cement cannot be moved through these tools. In addition, these types of traditional pills are not part of an efficient solution when severe losses occur or for combined events with gas migration; the limited concentration and type of LCM not forming a solid, hard, compact, and impermeable structure that could penetrate the formation and develops compressibility greater than 500 psi helping to control gas migration from deeper formations. The use of LCM technologies with high thixotropic rheological behavior fluids has become a good option based on a liquid phase with a very low solid size that has the property to transform from liquid to solid states depending on the operational requirements and temperature conditions. They have been able to be implemented in situations of loss of circulation control even with the use of directional tools. Another advantage is their setting and pumpable time adjusted according to specific situations, developing the desired thixotropy and reaching compressibility strength greater than 500 psi in really short time periods. The present study shows the successful application of a high thixotropy loss control system in a well located in the Middle Magdalena Valley basin in Colombia. In this region exposed formations present high pore pressure and low fracture pressure that caused simultaneously mud losses and well control events while tripping out with motor and MWD/LWD tools. Limited pump capability does not allow the implementation of traditional circulation pills generating a high probability of losing the tools in the hole or even losing the entire well. This document shows the first worldwide application of a high thixotropy pill technology through directional tools obtaining successful mud loss control, wellbore strengthening, and gas migration with positive results.
Relatórios de organizações sobre o assunto "Thixotropy"
1
Chanson, Hubert, Philippe Coussot, Sébastien Jarny e Laurent Tocquer. A Study of Dam Break Wave of Thixotropic Fluid: Bentonite Surges down an Inclined plane. The University of Queensland, Department of Civil Engineering, junho de 2004. http://dx.doi.org/10.14264/9437.
Texto completo da fonte