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Comprehensive Modelling Of Gas Condensate Relative Permeability And Its Influence On Field PerformanceCalisgan, Huseyin 01 September 2005 (has links) (PDF)
The productivity of most gas condensate wells is reduced significantly due to condensate banking when the bottom hole pressure falls below the dew point. The liquid drop-out in these very high rate gas wells may lead to low recovery problems. The most important parameter for determining condensate well productivity is the effective gas permeability in the near wellbore region, where very high velocities can occur. An understanding of the characteristics of the high-velocity gas-condensate flow and relative permeability data is necessary for accurate forecast of well productivity.
In order to tackle this goal, a series of two-phase drainage relative permeability measurements on a moderate permeability North Marmara &ndash / 1 gas well carbonate core plug sample, using a simple synthetic binary retrograde condensate fluid sample were conducted under reservoir conditions which corresponded to near miscible conditions. As a fluid system, the model of methanol/n-hexane system was used as a binary model that exhibits a critical point at ambient conditions. The interfacial tension by means of temperature and the flow rate were varied in the laboratory measurements. The laboratory experiments were repeated for the same conditions of interfacial tension and flow rate at immobile water saturation to observe the influence of brine saturation in gas condensate systems.
The laboratory experiment results show a clear trend from the immiscible relative permeability to miscible relative permeability lines with decreasing interfacial tension and increasing velocity. So that, if the interfacial tension is high and the flow velocity is low, the relative permeability functions clearly curved, whereas the relative permeability curves straighten as a linear at lower values of the interfacial tension and higher values of the flow velocity. The presence of the immobile brine saturation in the porous medium shows the same shape of behavior for relative permeability curves with a small difference that is the initial wetting phase saturations in the relative permeability curve shifts to the left in the presence of immobile water saturation.
A simple new mathematical model is developed to compute the gas and condensate relative permeabilities as a function of the three-parameter. It is called as condensate number / NK so that the new model is more sensitivity to temperature that represents implicitly the effect of interfacial tension. The new model generated the results were in good agreement with the literature data and the laboratory test results. Additionally, the end point relative permeability data and residual saturations satisfactorily correlate with literature data. The proposed model has fairly good fitness results for the condensate relative permeability curves compared to that of gas case. This model, with typical parameters for gas condensates, can be used to describe the relative permeability behavior and to run a compositional simulation study of a single well to better understand the productivity of the field.
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Optimum Design Of Pin-jointed 3-d Dome Structures Using Global Optimization TechniquesSarac, Yavuz 01 November 2005 (has links) (PDF)
Difficult gradient calculations, converging to a local optimum without exploring the design space adequately, too much dependency on the starting solution, lacking capabilities to treat discrete and mixed design variables are the main drawbacks of conventional optimization techniques. So evolutionary optimization methods received significant interest amongst researchers in the optimization area. Genetic
algorithms (GAs) and simulated annealing (SA) are the main representatives of evolutionary optimization methods. These techniques emerged as powerful and modern strategies to efficiently deal with the difficulties encountered in conventional techniques, and therefore rightly attracted a substantial interest and popularity. The underlying concepts of these techniques and thus their algorithmic models have been devised by establishing between the optimization task and events occurring in nature. While, Darwin& / #8217 / s survival of the fittest theory is mimicked by GAs, annealing process of physical systems are employed to SA.
On the other hand, dome structures are among the most preferred types of structures for large unobstructed areas. Domes have been of a special interest in the sense that
they enclose a maximum amount of space with a minimum surface. This feature provides economy in terms of consumption of constructional materials. So merging these two concepts make it possible to obtain optimum designs of dome structures.
This thesis is concerned with the use of GAs and SA in optimum structural design of dome structures, which range from some relatively simple problems to the problems of increased complexity. In this thesis, firstly both techniques are
investigated in terms of their practicality and applicability to the problems of interest. Then numerous test problems taken from real life conditions are studied for comparing the success of the proposed GA and SA techniques with other discrete
and continuous optimization methods. The results are discussed in detail to reach certain recommendations contributing to a more efficient use of the techniques in
optimum structural design of pin-jointed 3-D dome structures.
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Mathematical Modeling Of Horizontal Two-phase Flow Through Fully Eccentric AnnuliOmurlu, Cigdem 01 May 2006 (has links) (PDF)
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The primary objective of this study is to understand the mechanism, the
hydraulics and the characteristics, of the two-phase flow in horizontal annuli.
While achieving this goal, both theoretical and experimental works have been
conducted extensively. The METU-PETE-CTMFL (Middle East Technical
University, Petroleum and Natural Gas Engineering Department, Cuttings
Transport and Multiphase Flow Laboratory) multiphase flow loop consists of
4.84 m long eccentric horizontal acrylic pipes having 0.1143m inner diameter
(I.D) acrylic casing - 0.0571m outer diameter (O.D) drillpipe and 0.0932m I.D
acrylic casing - 0.0488m O.D drillipipe geometric configurations. During each
experiment, differential pressure loss data obtained from digital and analog
pressure transmitters at a given liquid and gas flow rate were recorded. The
flow patterns were identified visually. Meanwhile a mechanistic model has been
developed. The flow pattern identification criteria proposed originally for twophase
flow through pipes by Taitel and Dukler1 has been inherited and modified
for the eccentric annular geometry. The complex geometry of eccentric annuli
has been represented by a new single diameter definition, namely
representative diameter dr. The representative diameter has been used while
calculating the pressure losses. A computer code based on the algorithm of the
proposed mechanistic model has been developed in Matlab 7.0.4. Both the flow
pattern prediction and the frictional pressure loss estimation are compared with
the gathered experimental data. Moreover, friction factor correlations have
been developed for each flow pattern using experimental data and statistical
methods. The performance of the proposed model and the friction factor
correlations has been evaluated from experimental data. The mechanistic
model developed in this study accurately predicts flow pattern transitions and
frictional pressure losses. The model&rsquo / s pressure loss estimations are within
± / 30% for two different annular flow geometries.
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Zoneamento geotécnico geral do Distrito Federal: procedimentos metodológicos e sua inserção na gestão ambiental / General engineering geological zoning of the Federal District, Brazil: methodological proceeding and environmental management insertionRené Levy Aguiar 08 July 1997 (has links)
Nas diferentes metodologias de mapeamento geotécnico adotadas em inúmeros trabalhos no Brasil, o relacionamento dessa ferramenta com o processo de gestão ambiental apresenta graus de dificuldade variados, sobretudo na definição das unidades homogêneas que tenha significado objetivo na questão ambiental. O estudo realizado no Distrito Federal, abrangendo a totalidade de sua área (aproximadamente 5.814 Km2) apresenta seqüência operacional compatível com as exigências da escala 1:100.000, seguindo uma sistemática baseada principalmente nas propostas metodológicas adotadas no âmbito da Escola de Engenharia de São Carlos - EESC/USP, no sentido de contribuir tanto no conhecimento geotécnico local quanto no estabelecimento da importância do papel do mapeamento geotécnico nas diferentes fases do planejamento e implementação de ações de controle ambiental, em uma região que é normalmente o foco das atenções do país. Este trabalho analisa formas e classificação das informações, além da operacionalização das mesmas frente aos efeitos do diagnóstico e planejamento do espaço físico. São inseridas metodologias e modelos clássicos no tratamento do meio físico para a ordenação territorial e, principalmente, a sistemática aplicada e proposta para execução de trabalhos visando subsidiar o processo de gestão ambiental. / Due to its relevance, the definition relationship between the geotechnical units with environmental management has a major role in several engineering geological mapping methodologies used in many works in Brazil. A study in the Federal District-Brazil (5.814 km2) was done according with an operational sequence compatible with the 1:100.000 scale requirements. It follows a methodology based on differents concepts adopted at EESC/USP (Escola de Engenharia de São Carlos). This paper summarizes such procedures and includes some examples of their application, to add information to the local geotechnical knowledge and to show the importance of engineering geological mapping in many different periods of the planning and execution of the environmental control. This work analyses the incoming data and classify them, later show how to use them in the diagnostic and planning of physical space. This thesis summarizes several methodologies and classical models of physical environment for territorial zoning and specially introduces a systematic used in Federal District with the objective of subsides environmental management process.
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Micro-learning Platforms Brand Awareness Using Socialmedia Marketing and Customer Brand EngagementMujica, Alejandro, Villanueva, Esteban, Lodeiros-Zubiria, Manuel Luis 06 September 2021 (has links)
This study aims to analyse the impact of Social Media Marketing in Customer Brand Engagement and Brand Awareness micro-learning platforms. The sample consisted of 220 students from micro-learning platforms using social media in the educational institutions. Because social-media marketing and customer brand- engagement are second-order reflexive constructions, the two-stage approach of hierarchical models with mode-A was adopted. The results reveal that social media marketing influences both the building of customer brand engagement and brand awareness among students on micro-learning platforms. Furthermore, it was shown that customer brand engagement is an important mediator between social media marketing and brand awareness. Social-media marketing activities carried out by micro-learning platforms contribute to the generation of customer brand-engagement and brand awareness of these institutions. Furthermore, the results show that, although social-media marketing helps to generate brand-awareness, it is through customer brand-engagement that social-media marketing is most effective in generating brand-awareness. For micro-learning platforms, the results allow them to understand the importance of customer brand-engagement when using social-media marketing to generate brand-awareness.
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Strength Of Different Anatolian Sands In Wedge Shear, Triaxial Shear, And Shear Box TestsErzin, Yusuf 01 January 2004 (has links) (PDF)
Past studies on sands have shown that the shear strength measured in plane strain tests was higher than that measured in triaxial tests. It was observed that this difference changed with the friction angle & / #966 / cv at constant volume related to the mineralogical composition. In order to investigate the difference in strength measured in the wedge shear test, which approaches the plane strain condition, in the triaxial test, and in the shear box test, Anatolian sands were obtained from different locations in Turkey. Mineralogical analyses, identification tests, wedge shear tests (cylindrical wedge shear tests (cylwests) and prismatic wedge shear tests (priswests)), triaxial tests, and shear box tests were performed on these samples. In all shear tests, the shear strength measured was found to increase with the inclination & / #948 / of the shear plane to the bedding planes. Thus, cylwests (& / #948 / = 60o)
iii
yielded higher values of internal friction & / #966 / by about 3.6o than priswests (& / #948 / = 30o) under normal stresses between 17 kPa and 59 kPa. Values of & / #966 / measured in cylwests were about 1.08 times those measured in triaxial tests (& / #948 / & / #8776 / 65o), a figure close to the corresponding ratio of 1.13 found by past researchers between actual plane strain and triaxial test results. There was some indication that the difference between cylwest and triaxial test results increased with the & / #966 / cv value of the samples. With the smaller & / #948 / values (30o and 40o), priswests yielded nearly the same & / #966 / values as those obtained in triaxial tests under normal stresses between 20 kPa and 356 kPa. Shear box tests (& / #948 / =0o) yielded lower values of & / #966 / than cylwests (by about 7.9o), priswests (by about 4.4o), and triaxial tests (by about 4.2o) under normal stresses between 17 kPa and 48 kPa. It was shown that the shear strength measured in shear box tests showed an increase when & / #948 / was increased from 30o to 60o / this increase (about 4.2o) was of the order of the difference (about 3.6o) between priswest (& / #948 / = 30o) and cylwest (& / #948 / = 60o) results mentioned earlier. Shear box specimens with & / #948 / = 60o, prepared from the same batch of any sample as the corresponding cylwests, yielded & / #966 / values very close to those obtained in cylwests.
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