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Gary S Grest - One of the best experts on this subject based on the ideXlab platform.
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granular flow down a rough inclined plane transition between thin and thick piles
Physics of Fluids, 2003Co-Authors: Leonardo E Silbert, James W Landry, Gary S GrestAbstract:The rheology of granular particles in an inclined plane geometry is studied using three dimensional molecular dynamics simulations. The flow–No-Flow Boundary is determined for piles of varying heights over a range of inclination angles θ. Three angles determine the phase diagram: θr, the angle of repose, is the angle at which a flowing system comes to rest; θm, the maximum angle of stability, is the inclination required to induce flow in a static system; and θmax is the maximum angle for which stable, steady state flow is observed. In the stable flow region θr<θ<θmax, three flow regimes can be distinguished that depend on how close θ is to θr: (i) θ≫θr: Bagnold rheology, characterized by a mean particle velocity vx in the direction of flow that scales as vx∝h3/2, for a pile of height h, (ii) θ≳θr: The slow flow regime, characterized by a linear velocity profile with depth, and (iii) θ≈θr: Avalanche flow characterized by a slow underlying creep motion combined with occasional free surface events and large ...
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granular flow down a rough inclined plane transition between thin and thick piles
arXiv: Soft Condensed Matter, 2002Co-Authors: Leonardo E Silbert, James W Landry, Gary S GrestAbstract:The rheology of granular particles in an inclined plane geometry is studied using molecular dynamics simulations. The flow--No-Flow Boundary is determined for piles of varying heights over a range of inclination angles $\theta$. Three angles determine the phase diagram: $\theta_{r}$, the angle of repose, is the angle at which a flowing system comes to rest; $\theta_{m}$, the maximum angle of stability, is the inclination required to induce flow in a static system; and $\theta_{max}$ is the maximum angle for which stable, steady state flow is observed. In the stable flow region $\theta_{r} >\theta_{r}$: Bagnold rheology, characterized by a mean particle velocity $v_{x}$ in the direction of flow that scales as $v_{x}\propto h^{3/2}$, for a pile of height $h$, ii) $\theta\gtrsim\theta_{r}$: the slow flow regime, characterized by a linear velocity profile with depth, and iii) $\theta\approx\theta_{r}$: avalanche flow characterized by a slow underlying creep motion combined with occasional free surface events and large energy fluctuations. We also probe the physics of the initiation and cessation of flow. The results are compared to several recent experimental studies on chute flows and suggest that differences between measured velocity profiles in these experiments may simply be a consequence of how far the system is from jamming.
Pedro Marcelo - One of the best experts on this subject based on the ideXlab platform.
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Análise avançada de dados de produção em reservatórios naturalmente fraturados
[s.n.], 2018Co-Authors: Adrian Herbas, Pedro MarceloAbstract:Orientador: Rosângela Barros Zanoni Lopes MorenoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de GeociênciasResumo: Nos últimos anos tem havido um interesse crescente no uso dos métodos de Análise Avançada de Dados de Produção (AADP) para a descrição dinâmica do reservatório. A partir destes métodos analisam-se dados de produção diárias disponíveis, reduzindo a necessidade de operações de teste de poço, evitando perda de produção e com uma exatidão comparável à Análise de Transiente de Pressão. Diferentes modelos AADP têm sido propostos para reservatórios de óleo e gás homogêneos, de metano em camadas de carvão e de gás de xisto. No entanto, a produção de reservatórios naturalmente fraturados, tais como rochas carbonáticas ou siliciclásticas, ainda está sendo analisada como sistemas homogêneos utilizando métodos AADP atuais. Este trabalho apresenta a derivação analítica de dois métodos de AADP (Balanço de materiais dinâmico e curvas tipo de Blasingame) baseados no modelo de dupla porosidade, para analisar a produção diária de reservatórios naturalmente fraturado. Foram avaliados a transferência matriz-fratura pseudo-permanente e transiente (camadas e esferas). O desenvolvimento foi baseado nas soluções aproximadas de longo tempo da equação da difusividade em sistemas de dupla porosidade, para vazão constante em reservatórios fechados sem fluxo na fronteira. As aproximações foram comparadas com a solução exata, dada pela inversa da solução no espaço Laplace, obtida aplicando o algoritmo de Gaver-Stehfest. A validação foi feita usando dados de produção e pressão de fluxo sintéticos, gerados por um simulador numérico, e dados reais de campo de um reservatório de gás-condensado naturalmente fraturado. Os resultados confirmaram que reservatórios naturalmente fraturados com fluxo interporoso pseudo-permanente podem apresentar dois comportamentos dominado pelos limites do reservatório (fraturas y sistema total). A permeabilidade da fratura e o dano do poço são dependentes variáveis ômega e lambda. Reservatórios fraturados com fluxo interporoso transiente podem ser analisados utilizando técnicas de AADP atuais desenvolvidas para sistemas homogêneosAbstract: In recent years there has been an increasing interest in the use of Advanced Production Data Analysis (APDA) methods for dynamic reservoir description. These methods analyze available daily production data, reducing the need of well testing operations, avoiding production loss, with accuracy comparable to Pressure Transient Analysis (PTA). Different APDA models have been proposed for homogeneous, coalbed methane and shale gas reservoirs. Nevertheless, production from naturally fractured reservoirs, such as Carbonates or Siliciclastic, is still being analyzed as homogeneous systems with current APDA techniques. This work presents the analytical derivation of two APDA methods (Dynamic Material Balance and Blasingame Type Curves) based on the dual porosity model, to analyze daily production of Naturally Fractured Reservoirs (NFR). Both interporosity flow models between matrix and fractures, pseudosteady-state and transient (slabs and spheres), were evaluated. The development was based on long-time approximate solutions of diffusivity equation for constant flow rate in a closed system with No-Flow Boundary. These approximations were compared with the exact solution given in Laplace space, inverted to time domain applying the Gaver-Stehfest algorithm. The validation of the derived methods was made using synthetic production and flowing pressure data, generated by a numerical simulator, and real field data from a gas-condensate naturally fractured reservoir. Results confirmed that naturally fractured reservoirs with pseudosteady-state interporosity flow could present two Boundary-dominated behaviors (fracture and total systems). Fracture permeability and wellbore skin are functions of omega and lambda variables. Fractured reservoirs with transient interporosity flow between matrix and fracture system, can be analyzed using current APDA techniques developed for homogeneous systemsMestradoReservatórios e GestãoMestre em Ciências e Engenharia de Petróleo33003017CAPE
Pedro Marcelo Adrian Herbas - One of the best experts on this subject based on the ideXlab platform.
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Análise avançada de dados de produção em reservatórios naturalmente fraturados
2017Co-Authors: Pedro Marcelo Adrian HerbasAbstract:Resumo: Nos últimos anos tem havido um interesse crescente no uso dos métodos de Análise Avançada de Dados de Produção (AADP) para a descrição dinâmica do reservatório. A partir destes métodos analisam-se dados de produção diárias disponíveis, reduzindo a necessidade de operações de teste de poço, evitando perda de produção e com uma exatidão comparável à Análise de Transiente de Pressão. Diferentes modelos AADP têm sido propostos para reservatórios de óleo e gás homogêneos, de metano em camadas de carvão e de gás de xisto. No entanto, a produção de reservatórios naturalmente fraturados, tais como rochas carbonáticas ou siliciclásticas, ainda está sendo analisada como sistemas homogêneos utilizando métodos AADP atuais. Este trabalho apresenta a derivação analítica de dois métodos de AADP (Balanço de materiais dinâmico e curvas tipo de Blasingame) baseados no modelo de dupla porosidade, para analisar a produção diária de reservatórios naturalmente fraturado. Foram avaliados a transferência matriz-fratura pseudo-permanente e transiente (camadas e esferas). O desenvolvimento foi baseado nas soluções aproximadas de longo tempo da equação da difusividade em sistemas de dupla porosidade, para vazão constante em reservatórios fechados sem fluxo na fronteira. As aproximações foram comparadas com a solução exata, dada pela inversa da solução no espaço Laplace, obtida aplicando o algoritmo de Gaver-Stehfest. A validação foi feita usando dados de produção e pressão de fluxo sintéticos, gerados por um simulador numérico, e dados reais de campo de um reservatório de gás-condensado naturalmente fraturado. Os resultados confirmaram que reservatórios naturalmente fraturados com fluxo interporoso pseudo-permanente podem apresentar dois comportamentos dominado pelos limites do reservatório (fraturas y sistema total). A permeabilidade da fratura e o dano do poço são dependentes variáveis ômega e lambda. Reservatórios fraturados com fluxo interporoso transiente podem ser analisados utilizando técnicas de AADP atuais desenvolvidas para sistemas homogêneos.Abstract: In recent years there has been an increasing interest in the use of Advanced Production Data Analysis (APDA) methods for dynamic reservoir description. These methods analyze available daily production data, reducing the need of well testing operations, avoiding production loss, with accuracy comparable to Pressure Transient Analysis (PTA). Different APDA models have been proposed for homogeneous, coalbed methane and shale gas reservoirs. Nevertheless, production from naturally fractured reservoirs, such as Carbonates or Siliciclastic, is still being analyzed as homogeneous systems with current APDA techniques. This work presents the analytical derivation of two APDA methods (Dynamic Material Balance and Blasingame Type Curves) based on the dual porosity model, to analyze daily production of Naturally Fractured Reservoirs (NFR). Both interporosity flow models between matrix and fractures, pseudosteady-state and transient (slabs and spheres), were evaluated. The development was based on long-time approximate solutions of diffusivity equation for constant flow rate in a closed system with No-Flow Boundary. These approximations were compared with the exact solution given in Laplace space, inverted to time domain applying the Gaver-Stehfest algorithm. The validation of the derived methods was made using synthetic production and flowing pressure data, generated by a numerical simulator, and real field data from a gas-condensate naturally fractured reservoir. Results confirmed that naturally fractured reservoirs with pseudosteady-state interporosity flow could present two Boundary-dominated behaviors (fracture and total systems). Fracture permeability and wellbore skin are functions of omega and lambda variables. Fractured reservoirs with transient interporosity flow between matrix and fracture system, can be analyzed using current APDA techniques developed for homogeneous systems
Leonardo E Silbert - One of the best experts on this subject based on the ideXlab platform.
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granular flow down a rough inclined plane transition between thin and thick piles
Physics of Fluids, 2003Co-Authors: Leonardo E Silbert, James W Landry, Gary S GrestAbstract:The rheology of granular particles in an inclined plane geometry is studied using three dimensional molecular dynamics simulations. The flow–No-Flow Boundary is determined for piles of varying heights over a range of inclination angles θ. Three angles determine the phase diagram: θr, the angle of repose, is the angle at which a flowing system comes to rest; θm, the maximum angle of stability, is the inclination required to induce flow in a static system; and θmax is the maximum angle for which stable, steady state flow is observed. In the stable flow region θr<θ<θmax, three flow regimes can be distinguished that depend on how close θ is to θr: (i) θ≫θr: Bagnold rheology, characterized by a mean particle velocity vx in the direction of flow that scales as vx∝h3/2, for a pile of height h, (ii) θ≳θr: The slow flow regime, characterized by a linear velocity profile with depth, and (iii) θ≈θr: Avalanche flow characterized by a slow underlying creep motion combined with occasional free surface events and large ...
-
granular flow down a rough inclined plane transition between thin and thick piles
arXiv: Soft Condensed Matter, 2002Co-Authors: Leonardo E Silbert, James W Landry, Gary S GrestAbstract:The rheology of granular particles in an inclined plane geometry is studied using molecular dynamics simulations. The flow--No-Flow Boundary is determined for piles of varying heights over a range of inclination angles $\theta$. Three angles determine the phase diagram: $\theta_{r}$, the angle of repose, is the angle at which a flowing system comes to rest; $\theta_{m}$, the maximum angle of stability, is the inclination required to induce flow in a static system; and $\theta_{max}$ is the maximum angle for which stable, steady state flow is observed. In the stable flow region $\theta_{r} >\theta_{r}$: Bagnold rheology, characterized by a mean particle velocity $v_{x}$ in the direction of flow that scales as $v_{x}\propto h^{3/2}$, for a pile of height $h$, ii) $\theta\gtrsim\theta_{r}$: the slow flow regime, characterized by a linear velocity profile with depth, and iii) $\theta\approx\theta_{r}$: avalanche flow characterized by a slow underlying creep motion combined with occasional free surface events and large energy fluctuations. We also probe the physics of the initiation and cessation of flow. The results are compared to several recent experimental studies on chute flows and suggest that differences between measured velocity profiles in these experiments may simply be a consequence of how far the system is from jamming.
Adrian Herbas - One of the best experts on this subject based on the ideXlab platform.
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Análise avançada de dados de produção em reservatórios naturalmente fraturados
[s.n.], 2018Co-Authors: Adrian Herbas, Pedro MarceloAbstract:Orientador: Rosângela Barros Zanoni Lopes MorenoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de GeociênciasResumo: Nos últimos anos tem havido um interesse crescente no uso dos métodos de Análise Avançada de Dados de Produção (AADP) para a descrição dinâmica do reservatório. A partir destes métodos analisam-se dados de produção diárias disponíveis, reduzindo a necessidade de operações de teste de poço, evitando perda de produção e com uma exatidão comparável à Análise de Transiente de Pressão. Diferentes modelos AADP têm sido propostos para reservatórios de óleo e gás homogêneos, de metano em camadas de carvão e de gás de xisto. No entanto, a produção de reservatórios naturalmente fraturados, tais como rochas carbonáticas ou siliciclásticas, ainda está sendo analisada como sistemas homogêneos utilizando métodos AADP atuais. Este trabalho apresenta a derivação analítica de dois métodos de AADP (Balanço de materiais dinâmico e curvas tipo de Blasingame) baseados no modelo de dupla porosidade, para analisar a produção diária de reservatórios naturalmente fraturado. Foram avaliados a transferência matriz-fratura pseudo-permanente e transiente (camadas e esferas). O desenvolvimento foi baseado nas soluções aproximadas de longo tempo da equação da difusividade em sistemas de dupla porosidade, para vazão constante em reservatórios fechados sem fluxo na fronteira. As aproximações foram comparadas com a solução exata, dada pela inversa da solução no espaço Laplace, obtida aplicando o algoritmo de Gaver-Stehfest. A validação foi feita usando dados de produção e pressão de fluxo sintéticos, gerados por um simulador numérico, e dados reais de campo de um reservatório de gás-condensado naturalmente fraturado. Os resultados confirmaram que reservatórios naturalmente fraturados com fluxo interporoso pseudo-permanente podem apresentar dois comportamentos dominado pelos limites do reservatório (fraturas y sistema total). A permeabilidade da fratura e o dano do poço são dependentes variáveis ômega e lambda. Reservatórios fraturados com fluxo interporoso transiente podem ser analisados utilizando técnicas de AADP atuais desenvolvidas para sistemas homogêneosAbstract: In recent years there has been an increasing interest in the use of Advanced Production Data Analysis (APDA) methods for dynamic reservoir description. These methods analyze available daily production data, reducing the need of well testing operations, avoiding production loss, with accuracy comparable to Pressure Transient Analysis (PTA). Different APDA models have been proposed for homogeneous, coalbed methane and shale gas reservoirs. Nevertheless, production from naturally fractured reservoirs, such as Carbonates or Siliciclastic, is still being analyzed as homogeneous systems with current APDA techniques. This work presents the analytical derivation of two APDA methods (Dynamic Material Balance and Blasingame Type Curves) based on the dual porosity model, to analyze daily production of Naturally Fractured Reservoirs (NFR). Both interporosity flow models between matrix and fractures, pseudosteady-state and transient (slabs and spheres), were evaluated. The development was based on long-time approximate solutions of diffusivity equation for constant flow rate in a closed system with No-Flow Boundary. These approximations were compared with the exact solution given in Laplace space, inverted to time domain applying the Gaver-Stehfest algorithm. The validation of the derived methods was made using synthetic production and flowing pressure data, generated by a numerical simulator, and real field data from a gas-condensate naturally fractured reservoir. Results confirmed that naturally fractured reservoirs with pseudosteady-state interporosity flow could present two Boundary-dominated behaviors (fracture and total systems). Fracture permeability and wellbore skin are functions of omega and lambda variables. Fractured reservoirs with transient interporosity flow between matrix and fracture system, can be analyzed using current APDA techniques developed for homogeneous systemsMestradoReservatórios e GestãoMestre em Ciências e Engenharia de Petróleo33003017CAPE