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Environmental benefits riding the coattails of lean production : can an integration of environmental aspects and lean production result in synergies and a reduced risk of sub-opimisationHelldal, Michael, Tenne, Sofia, Lindahl, Mattias January 2009 (has links)
The purpose of this study was to investigate how work with Lean and environmental aspects affect one another, and if possible and beneficial from a business point-of-view, how they could be integrated into a single model. It was found that several of the fundamental concepts concerning Lean and environmental aspects support one another. Further, Lean has the potential to improve the environmental performance of a company, and can contributeto the environmental work by its proactive approach, structured way of operating and long-term way of thinking. The environmental perspective can contribute to Lean with its more holistic view; additional cost savingsand improvements might be found when looking at the operations from an environmental point-of-view. The study showed that it is not only possible to integrate Lean and environmental work, but that it also has the potential to be beneficial from both a business and an environmental standpoint. Integration can reduce the risk of sub-optimization, and synergies can be achieved. With this knowledge, the authors composed a model for how Lean and environmental work can be practised and integrated.
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A Hybrid Ensemble Kalman Filter for Nonlinear DynamicsWatanabe, Shingo 2009 December 1900 (has links)
In this thesis, we propose two novel approaches for hybrid Ensemble Kalman
Filter (EnKF) to overcome limitations of the traditional EnKF. The first approach is to
swap the ensemble mean for the ensemble mode estimation to improve the covariance
calculation in EnKF. The second approach is a coarse scale permeability constraint while
updating in EnKF. Both hybrid EnKF approaches are coupled with the streamline based
Generalized Travel Time Inversion (GTTI) algorithm for periodic updating of the mean
of the ensemble and to sequentially update the ensemble in a hybrid fashion.
Through the development of the hybrid EnKF algorithm, the characteristics of
the EnKF are also investigated. We found that the limits of the updated values constrain
the assimilation results significantly and it is important to assess the measurement error
variance to have a proper balance between preserving the prior information and the
observation data misfit. Overshooting problems can be mitigated with the streamline
based covariance localizations and normal score transformation of the parameters to
support the Gaussian error statistics.
The swapping mean and mode estimation approach can give us a better matching
of the data as long as the mode solution of the inversion process is satisfactory in terms
of matching the observation trajectory.
The coarse scale permeability constrained hybrid approach gives us better
parameter estimation in terms of capturing the main trend of the permeability field and
each ensemble member is driven to the posterior mode solution from the inversion
process. However the WWCT responses and pressure responses need to be captured
through the inversion process to generate physically plausible coarse scale permeability
data to constrain hybrid EnKF updating.
Uncertainty quantification methods for EnKF were developed to verify the
performance of the proposed hybrid EnKF compared to the traditional EnKF. The results
show better assimilation quality through a sequence of updating and a stable solution is
demonstrated.
The potential of the proposed hybrid approaches are promising through the
synthetic examples and a field scale application.
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Integration of dynamic data into reservoir description using streamline approachesHe, Zhong 15 November 2004 (has links)
Integration of dynamic data is critical for reliable reservoir description and has been an outstanding challenge for the petroleum industry. This work develops practical dynamic data integration techniques using streamline approaches to condition static geological models to various kinds of dynamic data, including two-phase production history, interference pressure observations and primary production data. The proposed techniques are computationally efficient and robust, and thus well-suited for large-scale field applications. We can account for realistic field conditions, such as gravity, and changing field conditions, arising from infill drilling, pattern conversion, and recompletion, etc., during the integration of two-phase production data. Our approach is fast and exhibits rapid convergence even when the initial model is far from the solution. The power and practical applicability of the proposed techniques are demonstrated with a variety of field examples.
To integrate two-phase production data, a travel-time inversion analogous to seismic inversion is adopted. We extend the method via a 'generalized travel-time' inversion to ensure matching of the entire production response rather than just a single time point while retaining most of the quasi-linear property of travel-time inversion. To integrate the interference pressure data, we propose an alternating procedure of travel-time inversion and peak amplitude inversion or pressure inversion to improve the overall matching of the pressure response.
A key component of the proposed techniques is the efficient computation of the sensitivities of dynamic responses with respect to reservoir parameters. These sensitivities are calculated analytically using a single forward simulation. Thus, our methods can be orders of magnitude faster than finite-difference based numerical approaches that require multiple forward simulations.
Streamline approach has also been extended to identify reservoir compartmentalization and flow barriers using primary production data in conjunction with decline type-curve analysis. The streamline 'diffusive' time of flight provides an effective way to calculate the drainage volume in 3D heterogeneous reservoirs. The flow barriers and reservoir compartmentalization are inferred based on the matching of drainage volumes from streamline-based calculation and decline type-curve analysis. The proposed approach is well-suited for application in the early stages of field development with limited well data and has been illustrated using a field example from the Gulf of Mexico.
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Fast history matching of finite-difference model, compressible and three-phase flow using streamline-derived sensitivitiesCheng, Hao 30 October 2006 (has links)
Reconciling high-resolution geologic models to field production history is still a very
time-consuming procedure. Recently streamline-based assisted and automatic history
matching techniques, especially production data integration by âÂÂtravel-time matching,âÂÂ
have shown great potential in this regard. But no systematic study was done to examine
the merits of travel-time matching compared to more traditional amplitude matching for
field-scale application. Besides, most applications were limited to two-phase water-oil
flow because current streamline models are limited in their ability to incorporate highly
compressible flow in a rigorous and computationally efficient manner.
The purpose of this work is fourfold. First, we quantitatively investigated the
nonlinearities in the inverse problems related to travel time, generalized travel time, and
amplitude matching during production data integration and their impact on the solution
and its convergence. Results show that the commonly used amplitude inversion can be
orders of magnitude more nonlinear compared to the travel-time inversion. Both the
travel-time and generalized travel time inversion (GTTI) are shown to be more robust
and exhibit superior convergence characteristics.
Second, the streamline-based assisted history matching was enhanced in two
important aspects that significantly improve its efficiency and effectiveness. We utilize
streamline-derived analytic sensitivities to determine the location and magnitude of the
changes to improve the history match, and we use the iterative GTTI for model updating.
Our approach leads to significant savings in time and manpower. Third, a novel approach to history matching finite-difference models that combines
the efficiency of analytical sensitivity computation of the streamline models with the
versatility of finite-difference simulation was developed. Use of finite-difference
simulation can account for complex physics.
Finally, we developed an approach to history matching three-phase flow using a
novel compressible streamline formulation and streamline-derived analytic sensitivities.
Streamline models were generalized to account for compressible flow by introducing a
relative density of total fluids along streamlines and a density-dependent source term in
the saturation equation. The analytical sensitivities are calculated based on the rigorous
streamline formulation.
The power and utility of our approaches have been demonstrated using both
synthetic and field examples.
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Time-lapse seismic monitoring of subsurface fluid flowYuh, Sung H. 30 September 2004 (has links)
Time-lapse seismic monitoring repeats 3D seismic imaging over a reservoir to map fluid movements in a reservoir. During hydrocarbon production, the fluid saturation, pressure, and temperature of a reservoir change, thereby altering the acoustic properties of the reservoir. Time-lapse seismic analysis can illuminate these dynamic
changes of reservoir properties, and therefore has strong potential for improving reservoir
management. However, the response of a reservoir depends on many parameters and can be diffcult to understand and predict. Numerical modeling results integrating streamline fluid flow simulation, rock physics, and ray-Born seismic modeling address some of these problems. Calculations show that the sensitivity of amplitude changes to porosity depend on the type of sediment comprising the reservoir. For consolidated rock, high-porosity models show
larger amplitude changes than low porosity models. However, in an unconsolidated
formation, there is less consistent correlation between amplitude and porosity. The
rapid time-lapse modeling schemes also allow statistical analysis of the uncertainty in
seismic response associated with poorly known values of reservoir parameters such as
permeability and dry bulk modulus. Results show that for permeability, the maximum
uncertainties in time-lapse seismic signals occur at the water front, where saturation is most variable. For the dry bulk-modulus, the uncertainty is greatest near the
injection well, where the maximum saturation changes occur. Time-lapse seismic methods can also be applied to monitor CO2 sequestration.
Simulations show that since the acoustic properties of CO2 are very different from
those of hydrocarbons and water, it is possible to image CO2 saturation using seismic
monitoring. Furthermore, amplitude changes after supercritical fluid CO2 injection
are larger than liquid CO2 injection.
Two seismic surveys over Teal South Field, Eugene Island, Gulf of Mexico, were acquired at different times, and the numerical models provide important insights to understand changes in the reservoir. 4D seismic differences after cross-equalization
show that amplitude dimming occurs in the northeast and brightening occurs in the
southwest part of the field. Our forward model, which integrates production data,
petrophysicals, and seismic wave propagation simulation, shows that the amplitude
dimming and brightening can be explained by pore pressure drops and gas invasion, respectively.
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A Hierarchical Multiscale Approach to History Matching and Optimization for Reservoir Management in Mature FieldsPark, Han-Young 2012 August 1900 (has links)
Reservoir management typically focuses on maximizing oil and gas recovery from a reservoir based on facts and information while minimizing capital and operating investments. Modern reservoir management uses history-matched simulation model to predict the range of recovery or to provide the economic assessment of different field development strategies. Geological models are becoming increasingly complex and more detailed with several hundred thousand to million cells, which include large sets of subsurface uncertainties. Current issues associated with history matching, therefore, involve extensive computation (flow simulations) time, preserving geologic realism, and non-uniqueness problem. Many of recent rate optimization methods utilize constrained optimization techniques, often making them inaccessible for field reservoir management. Field-scale rate optimization problems involve highly complex reservoir models, production and facilities constraints and a large number of unknowns.
We present a hierarchical multiscale calibration approach using global and local updates in coarse and fine grid. We incorporate a multiscale framework into hierarchical updates: global and local updates. In global update we calibrate large-scale parameters to match global field-level energy (pressure), which is followed by local update where we match well-by-well performances by calibration of local cell properties. The inclusion of multiscale calibration, integrating production data in coarse grid and successively finer grids sequentially, is critical for history matching high-resolution geologic models through significant reduction in simulation time.
For rate optimization, we develop a hierarchical analytical method using streamline-assisted flood efficiency maps. The proposed approach avoids use of complex optimization tools; rather we emphasize the visual and the intuitive appeal of streamline method and utilize analytic solutions derived from relationship between streamline time of flight and flow rates. The proposed approach is analytic, easy to implement and well-suited for large-scale field applications.
Finally, we present a hierarchical Pareto-based approach to history matching under conflicting information. In this work we focus on multiobjective optimization problem, particularly conflicting multiple objectives during history matching of reservoir performances. We incorporate Pareto-based multiobjective evolutionary algorithm and Grid Connectivity-based Transformation (GCT) to account for history matching with conflicting information.
The power and effectiveness of our approaches have been demonstrated using both synthetic and real field cases.
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Conservação de energia em sistemas de iluminação pública e os seus efeitos na rede elétrica de distribuição /Damato, Júlio Carlos. January 2005 (has links)
Resumo: O trabalho busca trazer uma contribuição na utilização da energia elétrica, através do melhor uso das lâmpadas de descarga à alta pressão, de vapor de mercúrio e de sódio. Dois aspectos são tratados: a influência deste tipo de lâmpada na qualidade de energia, uma vez que esta avaliação é difícil, por se tratar de uma carga distribuída por toda a cidade e o aspecto do dimensionamento dos condutores para os circuitos que têm uma alimentação exclusiva através de transformadores dedicados. A parte prática do trabalho está baseada em experimentos e medições feitas em uma subestação experimental montada no Laboratório de Alta Tensão na UNESP, campus de Guaratinguetá. Através de oscilografia, as formas de ondas de corrente e tensão, no lado de baixa tensão e média tensão, foram medidas, analisadas e avaliadas. Com a utilização de softwares gráficos foram comparadas as formas de ondas mostradas pelo equipamento com as curvas traçadas a partir de valores calculados. Foram avaliadas as influências dos transformadores de corrente e dos transformadores de potencial sobre as medições dos parâmetros elétricos de uma instalação. / Abstract: The work wants to give a contribution in the use of the electric power, trough the best use of the high pressure discharge lamps, of mercury and sodium. Two aspects are treated: the lamp type influence in Energy Quality, once this evaluation is difficult, for treating of a load distributed by the whole city, and the aspect of the dimensioning of the feeders for circuits that have and exclusive feeding through transformers.A brief revision of lighting concepts is made and also a study of harmonic current is presented. It was looked for, in research, to know the state of the art for the subject. The practical part of work is based on experiments and measurements made in a mounted experimental substation in UNESP High Tension Laboratory, campus of Guaratinguetá. Through oscilograph voltage and current waves formats, in low and high voltage sides, they were measured, analyzed and appraised. With utilization of graphics software was a made a comparison between the equipment oscilographed curves and curves acquire on calculated values. They were appraised the influences of voltage and current transformers about the measurents of the electric parameters of an installation. / Orientador: Oscar Armando Maldonado Astorga / Coorientador: José Luz Silveira / Banca: Agnelo Marotta Cassula / Banca: José Policarpo Gonçalves de Abreu / Mestre
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Conservação de energia em sistemas de iluminação pública e os seus efeitos na rede elétrica de distribuiçãoDamato, Júlio Carlos [UNESP] 21 December 2005 (has links) (PDF)
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damato_jc_me_guara.pdf: 907873 bytes, checksum: 1173d249b00c8dc682ed7ae9dce890c3 (MD5) / Universidade Estadual Paulista (UNESP) / O trabalho busca trazer uma contribuição na utilização da energia elétrica, através do melhor uso das lâmpadas de descarga à alta pressão, de vapor de mercúrio e de sódio. Dois aspectos são tratados: a influência deste tipo de lâmpada na qualidade de energia, uma vez que esta avaliação é difícil, por se tratar de uma carga distribuída por toda a cidade e o aspecto do dimensionamento dos condutores para os circuitos que têm uma alimentação exclusiva através de transformadores dedicados. A parte prática do trabalho está baseada em experimentos e medições feitas em uma subestação experimental montada no Laboratório de Alta Tensão na UNESP, campus de Guaratinguetá. Através de oscilografia, as formas de ondas de corrente e tensão, no lado de baixa tensão e média tensão, foram medidas, analisadas e avaliadas. Com a utilização de softwares gráficos foram comparadas as formas de ondas mostradas pelo equipamento com as curvas traçadas a partir de valores calculados. Foram avaliadas as influências dos transformadores de corrente e dos transformadores de potencial sobre as medições dos parâmetros elétricos de uma instalação. / The work wants to give a contribution in the use of the electric power, trough the best use of the high pressure discharge lamps, of mercury and sodium. Two aspects are treated: the lamp type influence in Energy Quality, once this evaluation is difficult, for treating of a load distributed by the whole city, and the aspect of the dimensioning of the feeders for circuits that have and exclusive feeding through transformers.A brief revision of lighting concepts is made and also a study of harmonic current is presented. It was looked for, in research, to know the state of the art for the subject. The practical part of work is based on experiments and measurements made in a mounted experimental substation in UNESP High Tension Laboratory, campus of Guaratinguetá. Through oscilograph voltage and current waves formats, in low and high voltage sides, they were measured, analyzed and appraised. With utilization of graphics software was a made a comparison between the equipment oscilographed curves and curves acquire on calculated values. They were appraised the influences of voltage and current transformers about the measurents of the electric parameters of an installation.
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Simulação por Linhas de Fluxo com Acoplamento GeomecânicoTEIXEIRA, Jonathan da Cunha 03 August 2015 (has links)
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Previous issue date: 2015-08-03 / ANP-PRH26 / Aimportânciadageomecânicaedoestudodeesquemasdeacoplamentoentreageomecânica
e fluxo multifásico têm sido cada vez mais importantes e utilizados pela indústria a
medida que formações cada vez mais profundas vêem sendo descobertas e exploradas.
O entendimento do comportamento do estado de tensão em um reservatório permite
produzir um melhor entendimento das implicações geomecânicas que ocorrem durante a
fase de explotação, isso porque durante esta fase, as alterações na poro-pressão conduzem
perturbações no equilíbrio mecânico afetando o estado de tensão de formações profundas,
de maneira a alterar as propriedades da rocha tais como permeabilidade e porosidade. No
entanto, a simulação acoplada (hidromecânica) em um grande campo heterogêneo implica
na solução de equações de fluxo e mecânica, associadas a um grande número de graus de
liberdade que torna esse tipo de abordagem inviável e computacionalmente cara. Neste
contexto, um simulador geomecânico-linhas de fluxoé apresentado dentro de um algoritmo
sequencial iterativo. Neste trabalho, aplica-se o método de elementos finitos com volume
de controle para o subproblema poro-mecânico que fornece um campo de velocidade de
Darcy pós-processado e a porosidade como entradas para o subproblema de transporte.
Este subproblema é resolvido através do método de decomposição de operador, no qual
basea-se em um esquema preditor-corretor com os passos preditor e corretor discretizados
pelos esquemas baseados em tempo de vôo e volumes finitos, respectivamente. Simulações
numéricas de injeção de água foram comparadas com soluções encontradas na literatura,
mostrando bons resultados. Em problemas dominados pela advecção, envolvendo um
reservatório naturalmente fraturado, a abordagem implementada foi capaz de predizer a
distribuição do campo de saturação ao longo de toda simulação. Além disso, para avaliar
a resposta geomecânica, simulações numéricas foram realizadas em um grande sistema
de reservatório-rocha capeadora em uma fase de recuperação primária de hidrocarboneto,
mostrou que a formulação apresentada provou ser: uma alternativa promissora para
simulação hidro-geomecânica tradicional; úteis para o modelo de fluxo de redução de
ordem nos casos em que o comportamento geomecânico são mais importantes do que o
comportamento de fluxo e de uma ferramenta complementar para simulação geomecânica
convencional. / The importance of geomechanics and the study of coupling between geomechanics and
multiphase flow have been increasingly recognized and used by the industry as deeper
formations are discovered and exploited. The knowledge of the state of stress in a reservoir
yields a better understanding of the geomechanical implications during exploitation stage,
because during the primary recovery stage, changes in pore pressure leads to perturbations
inthemechanicalequilibrium,affectingthestressstateintheformationsinawaythatalters
the rock properties such as permeability and porosity. However, the coupled simulation
(hydromechanical) in large field heterogeneous models involves stress and flow equations
solving, associated with a large number of degrees-of-freedom which becomes infeasible and
computationally costly. In this context, a geomechanical-streamline simulator is presented
within a iteratively coupled framework algorithm. In the present work, we applied control
volume finite element method for the poromechanics subproblem which provides a Darcy
velocityfieldthroughapost-processingvelocityprocedureandporosityasinputfieldstothe
transportsubproblem.Suchsubproblemissolvedbymeansofanoperatorsplittingmethod,
which is based on a predictor-corrector scheme with the predictor and corrector steps
discretized by a time-of-flight and a finite volume based schemes, respectively. Numerical
simulations of water-flooding are compared to the numerical results available in literature,
showing good results. In convection-dominated problems, involving a naturally fractured
reservoir, the approach was able to predict the saturation distributions for the whole
simulation correctly. Furthermore, to appraisal the geomechanical response, numerical
simulation was performed in a large reservoir-caprock system in a primary hydrocarbon
recovery stage, showing that the formulation presented proved be: an promising alternative
to traditional hydro-geomechanical simulation; useful for flow model order reduction in
cases where the geomechanical behavior are more important than the flow behavior and a
complementary tool for conventional geomechanical simulations.
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High Density Simulation of Crowds with Groups in Real-Time / Högdensitetssimulering av folkmassor med grupper i realtidShabo, Jack January 2017 (has links)
To simulate crowds of people is of great social interest and is also believed to be useful when analyzing situations involving denser crowds. Many simulators seen over the years have however been struggling with simulating larger number of people, often due to a computationally expensive collision avoidance step. Furthermore, many simulators seems to forget the fact that people tend to stick together in smaller social groups rather than walking alone. A simulator for high density crowds has nevertheless been implemented through modeling crowds as a unilateral incompressible fluid. Together with an integration of groups onto this approach, the obtained solution allows for real time simulation of up to 3000 virtual people. The impact of having groups in simulations has furthermore been set as the overall goal of the thesis and has been analyzed through observing the effects of groups in various scenarios. A smaller user study has also been conducted in order to gain perceptual insights of groups in various crowd densities. These have shown that groups have a smaller impact on the crowd flow, and do not put a larger strain on the performance of the simulation. Groups are further proved to be perceived differently in different densities, with a possible difficulty for scenarios in higher density. / Att simulera folkmassor är av stort socialt intresse och tros även vara till nytta när man analyserar situationer som berör mer kompaktare folkmassor. Många tidigare simulationer har dock kämpat med att simulera större folkmassor, oftast på grund av höga beräkningskostnader mot förhindrandet av att två eller fler virtuella människor kolliderar in i varandra. Dessutom verkar många simulationer glömma bort att människor oftast går i mindre sociala grupper snarare än att gå var och för sig hela tiden. En simulering har trots detta gjorts genom att modellera folkmassor som en unilateral inkompressibel vätska. Tillsammans med en integration av grupper på detta tillvägagångssätt har lösningen visat sig alltsomallt ge simulation i realtid för uppemot 3000 virtuella människor. Effekten av att ha grupper i simulationer har vidare analyserats i en rad olika scenarion. En mindre användarstudie har också gett insikter i hur grupper uppfattas i olika kompakta folkmassor. Resultat har visat att grupper har en mindre effekt på folkmassor i det stora hela, och lägger inte en alltför stor påfrestning på simulationers prestanda. Det har också bevisats att grupper uppfattas annorlunda i olika kompakta folkmassor, med en viss möjlighet till svårare uppfattning i högre, mer kompakta folkmassor.
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