The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform
Z. Schmidt - One of the best experts on this subject based on the ideXlab platform.
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Effect of viscosity on downhole Gas separation in a Rotary Gas Separator
Spe Production & Facilities, 2002Co-Authors: G. Lackner, Dale Doty, Siamack A. Shirazi, Z. SchmidtAbstract:Electrical submersible pump (ESP) installations are commonly used in the oil industry to aid fluid flow from the reservoir to the surface. As with any pump, the presence of free Gas at the pump intake can adversely affect the operation of an ESP. One method of reducing the amount of free Gas the pump has to process is to install a Rotary Gas Separator. In this work, the effect of viscosity on the Separator's performance is investigated. New experimental data were gathered that covered a broad range of operational conditions in terms of pressures, liquid flow rates, Gas-liquid ratios (GLRs), and rotational speeds. The experiments were conducted on a field-scale experimental facility with a commercially available Separator. The working fluids were water, two mineral oils, and air. An existing mechanistic model (based on physical principles) predicting the bottomhole Gas-separation efficiency in ESP installations was then evaluated with the data. Based on this investigation, improvements were implemented in the model to better capture the influence of viscosity on the downhole Gas-separation process. The results of the study indicate that there are two regions of separation efficiency with a pronounced transition between them: one region in which the Rotary Gas Separator is very effective (separation efficiencies between 80 and 100%), and the other in which it is not effective at all (separation efficiencies between 30 and 55%). The transition location depends on the fluid physical properties, operational conditions, and geometry of the Separator. The mechanistic model can predict this behavior and agrees well with the data that are obtained during this investigation. Fluid viscosity in the range of investigation (1 to 50 cp at 100°F) is found to have only little influence on Gas-separation efficiency. This may indicate that the effects of turbulence at high rotational speeds dominate the behavior of flow inside the Separator.
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Numerical simulation of the Gas-liquid flow in a Rotary Gas Separator
Journal of Energy Resources Technology-transactions of The Asme, 1998Co-Authors: G. Lackner, Dale Doty, Francisco J S Alhanati, Siamack A. Shirazi, Z. SchmidtAbstract:The presence of free Gas at pump intake adversely affects the performance of an electrical submersible pump (ESP) system, often resulting in low efficiency and causing operational problems. One method of reducing the amount of free Gas that the pump has to process is to install a Rotary Gas Separator. The Gas-liquid flow associated with the downhole installation of a Rotary Separator has been investigated to address its overall phase segregation performance. A mathematical model was developed to investigate factors contributing to Gas-liquid separation and to determine the efficiency of the Separator. The drift-flux approach was used to formulate this complex two-phase flow problem. The turbulent diffusivity was modeled by a two-layer mixing-length model and the relative velocity between phases was formulated based on published correlations for flows with similar characteristics. The well-known numerical procedure of Patankar-Spalding for single-phase flow computations was extended to this two-phase flow situation. Special discretization and techniques were developed to obtain consistent results. Special under-relaxation procedures were also developed to keep the Gas void fraction in the interval. Predicted mixture velocity vectors and Gas void fraction distribution for the two-phase flow inside the centrifuge are presented. The model`s predictions are compared to data gathered onmore » a field scale experimental facility to support its invaluable capabilities as a design tool for ESP installations.« less
Dale Doty - One of the best experts on this subject based on the ideXlab platform.
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Two-Phase Flow Modeling of Inducers
Journal of Energy Resources Technology, 2004Co-Authors: A.f. Harun, Mauricio Prado, Siamack A. Shirazi, Dale DotyAbstract:Inducers, which are classified as axial flow pumps with helical path blades, are used within Rotary Gas Separators commonly used in electrical submersible pump installations. A two-phase flow model has been developed to study the inducer performance, focusing on head generation. The proposed model is based on a meridional flow solution technique and utilizes a two-fluid approach. The model indicates that head degradation due to Gas presence is a function of flow pattern. The effect of flow pattern diminishes when the void fraction is greater than 15 percent since the centrifugal force dominates the interfacial drag force. In this case, the two-phase flow can be approximated as a homogeneous mixture. The model also suggests that a liquid displacement correction is needed when phase segregation occurs inside the inducer The new model significantly improves the ability to predict separation efficiency of a Rotary Gas Separator over existing models. Hydrocarbon-air and water-air experimental data were gathered to validate the new model.
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Effect of viscosity on downhole Gas separation in a Rotary Gas Separator
Spe Production & Facilities, 2002Co-Authors: G. Lackner, Dale Doty, Siamack A. Shirazi, Z. SchmidtAbstract:Electrical submersible pump (ESP) installations are commonly used in the oil industry to aid fluid flow from the reservoir to the surface. As with any pump, the presence of free Gas at the pump intake can adversely affect the operation of an ESP. One method of reducing the amount of free Gas the pump has to process is to install a Rotary Gas Separator. In this work, the effect of viscosity on the Separator's performance is investigated. New experimental data were gathered that covered a broad range of operational conditions in terms of pressures, liquid flow rates, Gas-liquid ratios (GLRs), and rotational speeds. The experiments were conducted on a field-scale experimental facility with a commercially available Separator. The working fluids were water, two mineral oils, and air. An existing mechanistic model (based on physical principles) predicting the bottomhole Gas-separation efficiency in ESP installations was then evaluated with the data. Based on this investigation, improvements were implemented in the model to better capture the influence of viscosity on the downhole Gas-separation process. The results of the study indicate that there are two regions of separation efficiency with a pronounced transition between them: one region in which the Rotary Gas Separator is very effective (separation efficiencies between 80 and 100%), and the other in which it is not effective at all (separation efficiencies between 30 and 55%). The transition location depends on the fluid physical properties, operational conditions, and geometry of the Separator. The mechanistic model can predict this behavior and agrees well with the data that are obtained during this investigation. Fluid viscosity in the range of investigation (1 to 50 cp at 100°F) is found to have only little influence on Gas-separation efficiency. This may indicate that the effects of turbulence at high rotational speeds dominate the behavior of flow inside the Separator.
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An Improved Model for Predicting Separation Efficiency of a Rotary Gas Separator in ESP Systems
Spe Production & Facilities, 2002Co-Authors: A.f. Harun, Mauricio Prado, Siamack A. Shirazi, Dale DotyAbstract:An improved model capable of predicting the separation efficiency of a Rotary Gas Separator (RGS) in electric submersible pump (ESP) systems is presented. The model incorporates a new, two-phase, flow-inducer model capable of calculating the inducer head. The inducer head, generated by an RGS, has been identified as a key parameter that distinguishes between a Separator's high- and low-efficiency regions. This information was previously determined empirically but can now be calculated. The new model more accurately predicts the maximum liquid rate at which an RGS should be installed. A comparison of the model's predictions with water/air and hydrocarbon/air experimental data indicates that the improved model performs better than earlier ones.
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Numerical simulation of the Gas-liquid flow in a Rotary Gas Separator
Journal of Energy Resources Technology-transactions of The Asme, 1998Co-Authors: G. Lackner, Dale Doty, Francisco J S Alhanati, Siamack A. Shirazi, Z. SchmidtAbstract:The presence of free Gas at pump intake adversely affects the performance of an electrical submersible pump (ESP) system, often resulting in low efficiency and causing operational problems. One method of reducing the amount of free Gas that the pump has to process is to install a Rotary Gas Separator. The Gas-liquid flow associated with the downhole installation of a Rotary Separator has been investigated to address its overall phase segregation performance. A mathematical model was developed to investigate factors contributing to Gas-liquid separation and to determine the efficiency of the Separator. The drift-flux approach was used to formulate this complex two-phase flow problem. The turbulent diffusivity was modeled by a two-layer mixing-length model and the relative velocity between phases was formulated based on published correlations for flows with similar characteristics. The well-known numerical procedure of Patankar-Spalding for single-phase flow computations was extended to this two-phase flow situation. Special discretization and techniques were developed to obtain consistent results. Special under-relaxation procedures were also developed to keep the Gas void fraction in the interval. Predicted mixture velocity vectors and Gas void fraction distribution for the two-phase flow inside the centrifuge are presented. The model`s predictions are compared to data gathered onmore » a field scale experimental facility to support its invaluable capabilities as a design tool for ESP installations.« less
Siamack A. Shirazi - One of the best experts on this subject based on the ideXlab platform.
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Two-Phase Flow Modeling of Inducers
Journal of Energy Resources Technology, 2004Co-Authors: A.f. Harun, Mauricio Prado, Siamack A. Shirazi, Dale DotyAbstract:Inducers, which are classified as axial flow pumps with helical path blades, are used within Rotary Gas Separators commonly used in electrical submersible pump installations. A two-phase flow model has been developed to study the inducer performance, focusing on head generation. The proposed model is based on a meridional flow solution technique and utilizes a two-fluid approach. The model indicates that head degradation due to Gas presence is a function of flow pattern. The effect of flow pattern diminishes when the void fraction is greater than 15 percent since the centrifugal force dominates the interfacial drag force. In this case, the two-phase flow can be approximated as a homogeneous mixture. The model also suggests that a liquid displacement correction is needed when phase segregation occurs inside the inducer The new model significantly improves the ability to predict separation efficiency of a Rotary Gas Separator over existing models. Hydrocarbon-air and water-air experimental data were gathered to validate the new model.
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Effect of viscosity on downhole Gas separation in a Rotary Gas Separator
Spe Production & Facilities, 2002Co-Authors: G. Lackner, Dale Doty, Siamack A. Shirazi, Z. SchmidtAbstract:Electrical submersible pump (ESP) installations are commonly used in the oil industry to aid fluid flow from the reservoir to the surface. As with any pump, the presence of free Gas at the pump intake can adversely affect the operation of an ESP. One method of reducing the amount of free Gas the pump has to process is to install a Rotary Gas Separator. In this work, the effect of viscosity on the Separator's performance is investigated. New experimental data were gathered that covered a broad range of operational conditions in terms of pressures, liquid flow rates, Gas-liquid ratios (GLRs), and rotational speeds. The experiments were conducted on a field-scale experimental facility with a commercially available Separator. The working fluids were water, two mineral oils, and air. An existing mechanistic model (based on physical principles) predicting the bottomhole Gas-separation efficiency in ESP installations was then evaluated with the data. Based on this investigation, improvements were implemented in the model to better capture the influence of viscosity on the downhole Gas-separation process. The results of the study indicate that there are two regions of separation efficiency with a pronounced transition between them: one region in which the Rotary Gas Separator is very effective (separation efficiencies between 80 and 100%), and the other in which it is not effective at all (separation efficiencies between 30 and 55%). The transition location depends on the fluid physical properties, operational conditions, and geometry of the Separator. The mechanistic model can predict this behavior and agrees well with the data that are obtained during this investigation. Fluid viscosity in the range of investigation (1 to 50 cp at 100°F) is found to have only little influence on Gas-separation efficiency. This may indicate that the effects of turbulence at high rotational speeds dominate the behavior of flow inside the Separator.
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An Improved Model for Predicting Separation Efficiency of a Rotary Gas Separator in ESP Systems
Spe Production & Facilities, 2002Co-Authors: A.f. Harun, Mauricio Prado, Siamack A. Shirazi, Dale DotyAbstract:An improved model capable of predicting the separation efficiency of a Rotary Gas Separator (RGS) in electric submersible pump (ESP) systems is presented. The model incorporates a new, two-phase, flow-inducer model capable of calculating the inducer head. The inducer head, generated by an RGS, has been identified as a key parameter that distinguishes between a Separator's high- and low-efficiency regions. This information was previously determined empirically but can now be calculated. The new model more accurately predicts the maximum liquid rate at which an RGS should be installed. A comparison of the model's predictions with water/air and hydrocarbon/air experimental data indicates that the improved model performs better than earlier ones.
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Numerical simulation of the Gas-liquid flow in a Rotary Gas Separator
Journal of Energy Resources Technology-transactions of The Asme, 1998Co-Authors: G. Lackner, Dale Doty, Francisco J S Alhanati, Siamack A. Shirazi, Z. SchmidtAbstract:The presence of free Gas at pump intake adversely affects the performance of an electrical submersible pump (ESP) system, often resulting in low efficiency and causing operational problems. One method of reducing the amount of free Gas that the pump has to process is to install a Rotary Gas Separator. The Gas-liquid flow associated with the downhole installation of a Rotary Separator has been investigated to address its overall phase segregation performance. A mathematical model was developed to investigate factors contributing to Gas-liquid separation and to determine the efficiency of the Separator. The drift-flux approach was used to formulate this complex two-phase flow problem. The turbulent diffusivity was modeled by a two-layer mixing-length model and the relative velocity between phases was formulated based on published correlations for flows with similar characteristics. The well-known numerical procedure of Patankar-Spalding for single-phase flow computations was extended to this two-phase flow situation. Special discretization and techniques were developed to obtain consistent results. Special under-relaxation procedures were also developed to keep the Gas void fraction in the interval. Predicted mixture velocity vectors and Gas void fraction distribution for the two-phase flow inside the centrifuge are presented. The model`s predictions are compared to data gathered onmore » a field scale experimental facility to support its invaluable capabilities as a design tool for ESP installations.« less
G. Lackner - One of the best experts on this subject based on the ideXlab platform.
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Effect of viscosity on downhole Gas separation in a Rotary Gas Separator
Spe Production & Facilities, 2002Co-Authors: G. Lackner, Dale Doty, Siamack A. Shirazi, Z. SchmidtAbstract:Electrical submersible pump (ESP) installations are commonly used in the oil industry to aid fluid flow from the reservoir to the surface. As with any pump, the presence of free Gas at the pump intake can adversely affect the operation of an ESP. One method of reducing the amount of free Gas the pump has to process is to install a Rotary Gas Separator. In this work, the effect of viscosity on the Separator's performance is investigated. New experimental data were gathered that covered a broad range of operational conditions in terms of pressures, liquid flow rates, Gas-liquid ratios (GLRs), and rotational speeds. The experiments were conducted on a field-scale experimental facility with a commercially available Separator. The working fluids were water, two mineral oils, and air. An existing mechanistic model (based on physical principles) predicting the bottomhole Gas-separation efficiency in ESP installations was then evaluated with the data. Based on this investigation, improvements were implemented in the model to better capture the influence of viscosity on the downhole Gas-separation process. The results of the study indicate that there are two regions of separation efficiency with a pronounced transition between them: one region in which the Rotary Gas Separator is very effective (separation efficiencies between 80 and 100%), and the other in which it is not effective at all (separation efficiencies between 30 and 55%). The transition location depends on the fluid physical properties, operational conditions, and geometry of the Separator. The mechanistic model can predict this behavior and agrees well with the data that are obtained during this investigation. Fluid viscosity in the range of investigation (1 to 50 cp at 100°F) is found to have only little influence on Gas-separation efficiency. This may indicate that the effects of turbulence at high rotational speeds dominate the behavior of flow inside the Separator.
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Numerical simulation of the Gas-liquid flow in a Rotary Gas Separator
Journal of Energy Resources Technology-transactions of The Asme, 1998Co-Authors: G. Lackner, Dale Doty, Francisco J S Alhanati, Siamack A. Shirazi, Z. SchmidtAbstract:The presence of free Gas at pump intake adversely affects the performance of an electrical submersible pump (ESP) system, often resulting in low efficiency and causing operational problems. One method of reducing the amount of free Gas that the pump has to process is to install a Rotary Gas Separator. The Gas-liquid flow associated with the downhole installation of a Rotary Separator has been investigated to address its overall phase segregation performance. A mathematical model was developed to investigate factors contributing to Gas-liquid separation and to determine the efficiency of the Separator. The drift-flux approach was used to formulate this complex two-phase flow problem. The turbulent diffusivity was modeled by a two-layer mixing-length model and the relative velocity between phases was formulated based on published correlations for flows with similar characteristics. The well-known numerical procedure of Patankar-Spalding for single-phase flow computations was extended to this two-phase flow situation. Special discretization and techniques were developed to obtain consistent results. Special under-relaxation procedures were also developed to keep the Gas void fraction in the interval. Predicted mixture velocity vectors and Gas void fraction distribution for the two-phase flow inside the centrifuge are presented. The model`s predictions are compared to data gathered onmore » a field scale experimental facility to support its invaluable capabilities as a design tool for ESP installations.« less
Francisco J S Alhanati - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of the Gas-liquid flow in a Rotary Gas Separator
Journal of Energy Resources Technology-transactions of The Asme, 1998Co-Authors: G. Lackner, Dale Doty, Francisco J S Alhanati, Siamack A. Shirazi, Z. SchmidtAbstract:The presence of free Gas at pump intake adversely affects the performance of an electrical submersible pump (ESP) system, often resulting in low efficiency and causing operational problems. One method of reducing the amount of free Gas that the pump has to process is to install a Rotary Gas Separator. The Gas-liquid flow associated with the downhole installation of a Rotary Separator has been investigated to address its overall phase segregation performance. A mathematical model was developed to investigate factors contributing to Gas-liquid separation and to determine the efficiency of the Separator. The drift-flux approach was used to formulate this complex two-phase flow problem. The turbulent diffusivity was modeled by a two-layer mixing-length model and the relative velocity between phases was formulated based on published correlations for flows with similar characteristics. The well-known numerical procedure of Patankar-Spalding for single-phase flow computations was extended to this two-phase flow situation. Special discretization and techniques were developed to obtain consistent results. Special under-relaxation procedures were also developed to keep the Gas void fraction in the interval. Predicted mixture velocity vectors and Gas void fraction distribution for the two-phase flow inside the centrifuge are presented. The model`s predictions are compared to data gathered onmore » a field scale experimental facility to support its invaluable capabilities as a design tool for ESP installations.« less
