This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneury...This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneurysm model was developed,and a self-designed piston pump was used to provide the pulsatile flow conditions.A fluid-structure interaction simulation was applied for comparison with and analysis of experimental findings.The maximum wall displacement oscillation increased as the pulsation frequency and outflow resistance increased,especially at the aneurysm dome.There is an obvious circular motion of the vortex center accompanying the periodic inflow fluctuation,and the pressure at the aneurysm dome at peak flow increased as the pulsatile flow frequency and terminal flow resistance increased.These results could explain why abnormal blood flow with high frequency and high outflow resistance is one of the risk factors for aneurysm rupture.展开更多
The effects of gravity,capillary force,and viscous force on the migration characteristics of oil and gas interface in oxygen-reduced air-assisted gravity drainage(OAGD)were studied through a two-dimensional visualizat...The effects of gravity,capillary force,and viscous force on the migration characteristics of oil and gas interface in oxygen-reduced air-assisted gravity drainage(OAGD)were studied through a two-dimensional visualization model.The effects of bond number,capillary number and low-temperature oxidation on OAGD recovery were studied by long core displacement experiments.On this basis,the low-temperature oxidation number was introduced and its relationship with the OAGD recovery was established.The results show that the shape and changing law of oil and gas front are mainly influenced by gravity,capillary force and viscous force.When the bond number is constant(4.52×10-4),the shape of oil-gas front is controlled by capillary number.When the capillary number is less than 1.68×10-3,the oil and gas interface is stable.When the capillary number is greater than 2.69×10-2,the oil and gas interface shows viscous fingering.When the capillary number is between 1.68×10-3 and 2.69×10-2,the oil and gas interface becomes capillary fingering.The core flooding experiments results show that for OAGD stable flooding,before the gas breakthrough,higher recovery is obtained in higher gravity number and lower capillary number.In this stage,gravity is predominant in controlling OAGD recovery and the oil recovery could be improved by reducing injection velocity.After gas breakthrough,higher recovery was obtained in lower gravity and higher capillary numbers,which means that the viscous force had a significant influence on the recovery.Increasing gas injection velocity in this stage is an effective measure to improve oil recovery.The low-temperature oxidation number has a good correlation with the recovery and can be used to predict the OAGD recovery.展开更多
The carcass layer of flexible pipe comprises a large-angle spiral structure with a complex interlocked stainless steel cross-section profile, which is mainly used to resist radial load. With the complex structure of t...The carcass layer of flexible pipe comprises a large-angle spiral structure with a complex interlocked stainless steel cross-section profile, which is mainly used to resist radial load. With the complex structure of the carcass layer, an equivalent simplified model is used to study the mechanical properties of the carcass layer. However, the current equivalent carcass model only considers the elastic deformation, and this simplification leads to huge errors in the calculation results. In this study, radial compression experiments were carried out to make the carcasses to undergo plastic deformation. Subsequently, a residual neural network based on the experimental data was established to predict the load-displacement curves of carcasses with different inner diameter in plastic states under radial compression.The established neural network model’s high precision was verified by experimental data, and the influence of the number of input variables on the accuracy of the neural network was discussed. The conclusion shows that the residual neural network model established based on the experimental data of the small-diameter carcass layer can predict the load-displacement curve of the large-diameter carcass layer in the plastic stage. With the decrease of input data, the prediction accuracy of residual network model in plasticity stage will decrease.展开更多
Oil saturation is a critical parameter when designing oil field development plans.This study focuses on the change of oil saturation during water flooding.Particularly,a meter-level artificial model is used to conduct...Oil saturation is a critical parameter when designing oil field development plans.This study focuses on the change of oil saturation during water flooding.Particularly,a meter-level artificial model is used to conduct relevant experiments on the basis of similarity principles and taking into account the layer geological characteristics of the reservoir.The displacement experiment’s total recovery rate is 41.35%.The changes in the remaining oil saturation at a millimeter-scale are examined using medical spiral computer tomography principles.In all experimental stages,regions exists where the oil saturation decline is more than 10.0%.The shrinkage percentage is 20.70%in the horizontal well production stage.The oil saturation reduction in other parts is less than 10.0%,and there are regions where the oil saturation increases in the conventional water flooding stage.展开更多
An essential technology of carbon capture, utilization and storage-enhanced oil recovery (CCUS-EOR) for tight oil reservoirs is CO_(2) huff-puff followed by associated produced gas reinjection. In this paper, the effe...An essential technology of carbon capture, utilization and storage-enhanced oil recovery (CCUS-EOR) for tight oil reservoirs is CO_(2) huff-puff followed by associated produced gas reinjection. In this paper, the effects of multi-component gas on the properties and components of tight oil are studied. First, the core displacement experiments using the CH_(4)/CO_(2) multi-component gas are conducted to determine the oil displacement efficiency under different CO_(2) and CH_(4) ratios. Then, a viscometer and a liquid density balance are used to investigate the change characteristics of oil viscosity and density after multi-component gas displacement with different CO_(2) and CH_(4) ratios. In addition, a laboratory scale numerical model is established to validate the experimental results. Finally, a composition model of multi-stage fractured horizontal well in tight oil reservoir considering nano-confinement effects is established to investigate the effects of multi-component gas on the components of produced dead oil and formation crude oil. The experimental results show that the oil displacement efficiency of multi-component gas displacement is greater than that of single-component gas displacement. The CH_(4) decreases the viscosity and density of light oil, while CO_(2) decreases the viscosity but increases the density. And the numerical simulation results show that CO_(2) extracts more heavy components from the liquid phase into the vapor phase, while CH_(4) extracts more light components from the liquid phase into the vapor phase during cyclic gas injection. The multi-component gas can extract both the light components and the heavy components from oil, and the balanced production of each component can be achieved by using multi-component gas huff-puff.展开更多
To study the characteristics of attenuation, hydrostatic towage and wave response of the vertical-axis floating tidal current energy power generation device (VAFTCEPGD), a prototype is designed and experiment is car...To study the characteristics of attenuation, hydrostatic towage and wave response of the vertical-axis floating tidal current energy power generation device (VAFTCEPGD), a prototype is designed and experiment is carried out in the towing tank. Free decay is conducted to obtain attenuation characteristics of the VAFTCEPGD, and characteristics of mooring forces and motion response, floating condition, especially the lateral displacement of the VAFTCEPGD are obtained from the towing in still water. Tension response of the #1 mooring line and vibration characteristics of the VAFTCEPGD in regular waves as well as in level 4 irregular wave sea state with the current velocity of 0.6 m/s. The results can be reference for theoretical study and engineering applications related to VAFTCEPGD.展开更多
The numerical simulation of polymer flooding is a complex task as this process involves complex physical and chemical reactions,and multiple sets of characteristic parameters are required to properly set the simulatio...The numerical simulation of polymer flooding is a complex task as this process involves complex physical and chemical reactions,and multiple sets of characteristic parameters are required to properly set the simulation.At present,such characteristic parameters are mainly obtained by empirical methods,which typically result in relatively large errors.By analyzing experimentally polymer adsorption,permeability decline,inaccessible pore volume,viscosity-concentration relationship,and rheology,in this study,a conversion equation is provided to convert the experimental data into the parameters needed for the numerical simulation.Some examples are provided to demonstrate the reliability of the proposed approach.展开更多
Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an op...Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an optical fibre displacement sensor(OFBDS)with simple structure and high measurement accuracy,the unified model of the commonly used OFBDS structures was proposed and the feasibility of the intensity⁃modulation of multi⁃structural optical fibre bundles was analysed based on the arrangement characteristics of the fibre bundle end⁃face.The intensity⁃modulation characteristic of different fibre bundles was analysed,and the single coil coaxial fibre bundle was chosen as the fibre probe in this study.The sensor hardware system was designed.Lastly,the calibration experiment,temperature interference experiment,changes of measured plane surface area,and the dynamic experiment were conducted.Results showed that the sensor linear measurement range was about 3 mm,and the sensor system had excellent static and dynamic characteristics.展开更多
C oilfield is located in Bohai Bay Basin, a typical strong bottom water reservoir. There is a large amount of remaining oil in the plane and vertical direction, which cannot be used. Therefore, it is urgent to explore...C oilfield is located in Bohai Bay Basin, a typical strong bottom water reservoir. There is a large amount of remaining oil in the plane and vertical direction, which cannot be used. Therefore, it is urgent to explore the feasibility of changing the development mode of typical sand bodies and displacement mining. In this study, the residual distribution of the bottom water reservoir is studied through numerical simulation. According to the distribution of remaining oil in the middle of the two sand bodies and the local structure of the sand body, it is divided into top remaining oil, edge remaining oil, and inter well-remaining oil. The effects of different angular permeability laws and differential and injected medium on the development effect are simulated and analyzed. It is found that the effect of gas injection is affected by a high mobility ratio, which is easy to break through early, and the effect of gas channeling is limited. Using active water and air-water alternate (ammonia foam) can achieve relatively good results. This experimental study guides tapping the remaining oil potential in the offshore strong bottom water reservoir.展开更多
The behavior of cold⁃formed steel(CFS)stud⁃to⁃sheathing connections at elevated temperatures is an important parameter for the fire resistance design and modeling of mid⁃rise CFS structures.In this paper,three kinds o...The behavior of cold⁃formed steel(CFS)stud⁃to⁃sheathing connections at elevated temperatures is an important parameter for the fire resistance design and modeling of mid⁃rise CFS structures.In this paper,three kinds of sheathings,namely,medium⁃and low⁃density calcium⁃silicate boards and oriented strand board,were selected for double⁃shear experiments on the mechanical properties of 253 screw connections at ambient and elevated temperatures.The effects of the shear direction,screw edge distance and the number of screws on the behavior of the connections were studied.The results showed that the shear direction and the screw edge distance more significantly influenced the peak deformation,while their impacts on the peak load varied with the type of sheathings.Compared with the single⁃screw connections,the peak loads of the specimens with double⁃screw connections obviously increased but did not double.Finally,a simplified load⁃displacement curve model of stud⁃to⁃sheathing connections at elevated temperature was generated first by establishing the prediction formula for characteristic parameters,such as the peak load,the peak deformation and the elastic stiffness,and then by considering whether the curves corresponded to stiffness increase phenomena.The present investigation provides basic data for future studies on the numerical modeling of CFS structures under fire conditions.展开更多
Based on simulation experiments of a number of scientific research items, the latest progress of experiment method and test technique about equivalent material simulation are introduced. The bevelopment of experiment ...Based on simulation experiments of a number of scientific research items, the latest progress of experiment method and test technique about equivalent material simulation are introduced. The bevelopment of experiment technique makes analogy simulation evolve into quantitative research about support-surrounding rock relationship from qualitative experiment.From this, large scale stereoscopic simulation experiment is developed, which has never appeared in underground pressure research in China. The present mold specification is 3 - 6 m×2. 0 m ×1. 5 m.展开更多
基金This study was supported by the National Natural Science Foundation of China(Grants 11602053 and 51576033)the Fundamental Research Funds for the Central Universities(Grant DUT18JC23).
文摘This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneurysm model was developed,and a self-designed piston pump was used to provide the pulsatile flow conditions.A fluid-structure interaction simulation was applied for comparison with and analysis of experimental findings.The maximum wall displacement oscillation increased as the pulsation frequency and outflow resistance increased,especially at the aneurysm dome.There is an obvious circular motion of the vortex center accompanying the periodic inflow fluctuation,and the pressure at the aneurysm dome at peak flow increased as the pulsatile flow frequency and terminal flow resistance increased.These results could explain why abnormal blood flow with high frequency and high outflow resistance is one of the risk factors for aneurysm rupture.
基金Supported by the National Science and Technology Major Project(ZX20170054)
文摘The effects of gravity,capillary force,and viscous force on the migration characteristics of oil and gas interface in oxygen-reduced air-assisted gravity drainage(OAGD)were studied through a two-dimensional visualization model.The effects of bond number,capillary number and low-temperature oxidation on OAGD recovery were studied by long core displacement experiments.On this basis,the low-temperature oxidation number was introduced and its relationship with the OAGD recovery was established.The results show that the shape and changing law of oil and gas front are mainly influenced by gravity,capillary force and viscous force.When the bond number is constant(4.52×10-4),the shape of oil-gas front is controlled by capillary number.When the capillary number is less than 1.68×10-3,the oil and gas interface is stable.When the capillary number is greater than 2.69×10-2,the oil and gas interface shows viscous fingering.When the capillary number is between 1.68×10-3 and 2.69×10-2,the oil and gas interface becomes capillary fingering.The core flooding experiments results show that for OAGD stable flooding,before the gas breakthrough,higher recovery is obtained in higher gravity number and lower capillary number.In this stage,gravity is predominant in controlling OAGD recovery and the oil recovery could be improved by reducing injection velocity.After gas breakthrough,higher recovery was obtained in lower gravity and higher capillary numbers,which means that the viscous force had a significant influence on the recovery.Increasing gas injection velocity in this stage is an effective measure to improve oil recovery.The low-temperature oxidation number has a good correlation with the recovery and can be used to predict the OAGD recovery.
基金financially supported by the National Key R&D Program of China (2021YFA1003501)the National Natural Science Foundation of China (No.U1906233,11732004)the Fundamental Research Funds for the Central Universities (DUT20ZD213,DUT20LAB308)。
文摘The carcass layer of flexible pipe comprises a large-angle spiral structure with a complex interlocked stainless steel cross-section profile, which is mainly used to resist radial load. With the complex structure of the carcass layer, an equivalent simplified model is used to study the mechanical properties of the carcass layer. However, the current equivalent carcass model only considers the elastic deformation, and this simplification leads to huge errors in the calculation results. In this study, radial compression experiments were carried out to make the carcasses to undergo plastic deformation. Subsequently, a residual neural network based on the experimental data was established to predict the load-displacement curves of carcasses with different inner diameter in plastic states under radial compression.The established neural network model’s high precision was verified by experimental data, and the influence of the number of input variables on the accuracy of the neural network was discussed. The conclusion shows that the residual neural network model established based on the experimental data of the small-diameter carcass layer can predict the load-displacement curve of the large-diameter carcass layer in the plastic stage. With the decrease of input data, the prediction accuracy of residual network model in plasticity stage will decrease.
基金supported by the National Science and Technology Major Projects of China for Oil and Gas(Projects Nos.2016ZX05010 and 2016ZX05058).
文摘Oil saturation is a critical parameter when designing oil field development plans.This study focuses on the change of oil saturation during water flooding.Particularly,a meter-level artificial model is used to conduct relevant experiments on the basis of similarity principles and taking into account the layer geological characteristics of the reservoir.The displacement experiment’s total recovery rate is 41.35%.The changes in the remaining oil saturation at a millimeter-scale are examined using medical spiral computer tomography principles.In all experimental stages,regions exists where the oil saturation decline is more than 10.0%.The shrinkage percentage is 20.70%in the horizontal well production stage.The oil saturation reduction in other parts is less than 10.0%,and there are regions where the oil saturation increases in the conventional water flooding stage.
基金supported by the National Natural Science Foundation of China(No.52174038 and No.52004307)China Petroleum Science and Technology Project-major project-Research on tight oil-shale oil reservoir engineering methods and key technologies in Ordos Basin(ZLZX2020-02-04)Science Foundation of China University of Petroleum,Beijing(No.2462018YJRC015).
文摘An essential technology of carbon capture, utilization and storage-enhanced oil recovery (CCUS-EOR) for tight oil reservoirs is CO_(2) huff-puff followed by associated produced gas reinjection. In this paper, the effects of multi-component gas on the properties and components of tight oil are studied. First, the core displacement experiments using the CH_(4)/CO_(2) multi-component gas are conducted to determine the oil displacement efficiency under different CO_(2) and CH_(4) ratios. Then, a viscometer and a liquid density balance are used to investigate the change characteristics of oil viscosity and density after multi-component gas displacement with different CO_(2) and CH_(4) ratios. In addition, a laboratory scale numerical model is established to validate the experimental results. Finally, a composition model of multi-stage fractured horizontal well in tight oil reservoir considering nano-confinement effects is established to investigate the effects of multi-component gas on the components of produced dead oil and formation crude oil. The experimental results show that the oil displacement efficiency of multi-component gas displacement is greater than that of single-component gas displacement. The CH_(4) decreases the viscosity and density of light oil, while CO_(2) decreases the viscosity but increases the density. And the numerical simulation results show that CO_(2) extracts more heavy components from the liquid phase into the vapor phase, while CH_(4) extracts more light components from the liquid phase into the vapor phase during cyclic gas injection. The multi-component gas can extract both the light components and the heavy components from oil, and the balanced production of each component can be achieved by using multi-component gas huff-puff.
基金supported by the National Natural Science Foundation of China(Grant Nos.51309068,51309069,51579055 and 11572094)the Special Funded of Innovational Talents of Science and Technology in Harbin(Grant No.RC2014QN001008)+1 种基金the China Postdoctoral Science Foundation(Grant Nos.2014M561334 and 2015T80330)the Heilongjiang Postdoctoral Science Foundation(Grant No.LBH-Z14060)
文摘To study the characteristics of attenuation, hydrostatic towage and wave response of the vertical-axis floating tidal current energy power generation device (VAFTCEPGD), a prototype is designed and experiment is carried out in the towing tank. Free decay is conducted to obtain attenuation characteristics of the VAFTCEPGD, and characteristics of mooring forces and motion response, floating condition, especially the lateral displacement of the VAFTCEPGD are obtained from the towing in still water. Tension response of the #1 mooring line and vibration characteristics of the VAFTCEPGD in regular waves as well as in level 4 irregular wave sea state with the current velocity of 0.6 m/s. The results can be reference for theoretical study and engineering applications related to VAFTCEPGD.
基金supported by Hubei Provincial Natural Science Foundation of China(Grant No.2020CFB377)the National Natural Science Foundation of China(Grant No.52104020).
文摘The numerical simulation of polymer flooding is a complex task as this process involves complex physical and chemical reactions,and multiple sets of characteristic parameters are required to properly set the simulation.At present,such characteristic parameters are mainly obtained by empirical methods,which typically result in relatively large errors.By analyzing experimentally polymer adsorption,permeability decline,inaccessible pore volume,viscosity-concentration relationship,and rheology,in this study,a conversion equation is provided to convert the experimental data into the parameters needed for the numerical simulation.Some examples are provided to demonstrate the reliability of the proposed approach.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51775260)the Qinglan Project of Jiangsu Province(2017)of China and the Funds of Nanjing Institute of Technology(Grant No.CKJA201801).
文摘Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an optical fibre displacement sensor(OFBDS)with simple structure and high measurement accuracy,the unified model of the commonly used OFBDS structures was proposed and the feasibility of the intensity⁃modulation of multi⁃structural optical fibre bundles was analysed based on the arrangement characteristics of the fibre bundle end⁃face.The intensity⁃modulation characteristic of different fibre bundles was analysed,and the single coil coaxial fibre bundle was chosen as the fibre probe in this study.The sensor hardware system was designed.Lastly,the calibration experiment,temperature interference experiment,changes of measured plane surface area,and the dynamic experiment were conducted.Results showed that the sensor linear measurement range was about 3 mm,and the sensor system had excellent static and dynamic characteristics.
文摘C oilfield is located in Bohai Bay Basin, a typical strong bottom water reservoir. There is a large amount of remaining oil in the plane and vertical direction, which cannot be used. Therefore, it is urgent to explore the feasibility of changing the development mode of typical sand bodies and displacement mining. In this study, the residual distribution of the bottom water reservoir is studied through numerical simulation. According to the distribution of remaining oil in the middle of the two sand bodies and the local structure of the sand body, it is divided into top remaining oil, edge remaining oil, and inter well-remaining oil. The effects of different angular permeability laws and differential and injected medium on the development effect are simulated and analyzed. It is found that the effect of gas injection is affected by a high mobility ratio, which is easy to break through early, and the effect of gas channeling is limited. Using active water and air-water alternate (ammonia foam) can achieve relatively good results. This experimental study guides tapping the remaining oil potential in the offshore strong bottom water reservoir.
基金the National Natural Science Foundation of China(Grant No.51978655)the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20201347)+1 种基金the Xuzhou Science and Technology Project(Grant No.KC20175)the China Postdoctoral Science Foundation Funded Project(Grant No.2019M652007).
文摘The behavior of cold⁃formed steel(CFS)stud⁃to⁃sheathing connections at elevated temperatures is an important parameter for the fire resistance design and modeling of mid⁃rise CFS structures.In this paper,three kinds of sheathings,namely,medium⁃and low⁃density calcium⁃silicate boards and oriented strand board,were selected for double⁃shear experiments on the mechanical properties of 253 screw connections at ambient and elevated temperatures.The effects of the shear direction,screw edge distance and the number of screws on the behavior of the connections were studied.The results showed that the shear direction and the screw edge distance more significantly influenced the peak deformation,while their impacts on the peak load varied with the type of sheathings.Compared with the single⁃screw connections,the peak loads of the specimens with double⁃screw connections obviously increased but did not double.Finally,a simplified load⁃displacement curve model of stud⁃to⁃sheathing connections at elevated temperature was generated first by establishing the prediction formula for characteristic parameters,such as the peak load,the peak deformation and the elastic stiffness,and then by considering whether the curves corresponded to stiffness increase phenomena.The present investigation provides basic data for future studies on the numerical modeling of CFS structures under fire conditions.
文摘Based on simulation experiments of a number of scientific research items, the latest progress of experiment method and test technique about equivalent material simulation are introduced. The bevelopment of experiment technique makes analogy simulation evolve into quantitative research about support-surrounding rock relationship from qualitative experiment.From this, large scale stereoscopic simulation experiment is developed, which has never appeared in underground pressure research in China. The present mold specification is 3 - 6 m×2. 0 m ×1. 5 m.