Tetrahydrofuran（THF） was selected as the substitute to study the flow behaviors and the mechanism of the hydrates blockage in pipelines.The slurrylike hydrates and slushlike hydrates are observed with the formation ...Tetrahydrofuran（THF） was selected as the substitute to study the flow behaviors and the mechanism of the hydrates blockage in pipelines.The slurrylike hydrates and slushlike hydrates are observed with the formation of hydrates in pipeline.There is a critical hydrate volume concentration of 50.6% for THF slurries and pipeline will be free of hydrate blockage while the hydrate volume concentration is lower than the critical volume concentration;otherwise,pipeline will be easy to be blocked.Fully turbulent flow occurs and friction factors tend to be constant when the velocity reaches 1.5 m/s.And then,constant values of friction factors that depend on the volume concentrations in the slurry were regressed to estimate the pressure drops of THF hydrate slurry at large mean velocity.Finally,a safe region,defined according to the critical hydrate volume concentration,was proposed for THF hydrate slurry,which may provide some insight for further studying the natural gas hydrate slurries and judge whether the pipeline can be run safely or not.展开更多
The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and th...The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and the simulation is carried out by using finite difference method. The results show that the lubricant flow status and end leakage quantity are greatly influenced by spiral angle,and that the rotating speed has little influence on the flow status. With advisable geometry design, the separation of lubricant between different oil wedges can be obtained, which can decrease the temperature rise effectively.展开更多
CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposit...CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.展开更多
In order to study the high temperature flow behaviour of the V modified 2.25Cr-1Mo steel plate to guide the industrial rolling practice, the hot compression tests were carried out at the temperatures from 900 ℃ to 11...In order to study the high temperature flow behaviour of the V modified 2.25Cr-1Mo steel plate to guide the industrial rolling practice, the hot compression tests were carried out at the temperatures from 900 ℃ to 1150 ℃ and the strain rates from 0.01s^-1 to 1 s^-1 on Thermecmastor-Z equipment. Based on the experimental data of the hot compression tests, a kind of Arrhenius-type constitutive equation was developed.The equation can accurately show the relationship between the flow stress and the deformation temperature, the strain and the strain rate. The measured true stress-true strain curves exhibit two kinds of flow stress curves. Moreover, the forming mechanisms of these two types curves were explained by softening, wok hardening theory as well as metallographic and hardness experimental results. The accuracy of the developed Arrheniustype constitutive equation was identified by three kinds of statistic parameters and also by comparison of the measured and predicted data. The reasonable value of the three types of statistic parameters and the good agreement between the experimental and predicted data can confirm the validity of the developed Arrheniustype constitutive equation for V modified 2.25 Cr-1 Mo heat resistant steel plate.展开更多
Field development typically requires detailed petrophysical analysis and well defined hydraulic flow units for comprehensive formation evaluation and reservoir characterization. In the present study, pay zones petroph...Field development typically requires detailed petrophysical analysis and well defined hydraulic flow units for comprehensive formation evaluation and reservoir characterization. In the present study, pay zones petrophysics are studied using an assembly of well log data from 8 wells together with core plugs measurements. Petrophysical analysis showed a good reservoir quality with average water saturation increasing toward the East and Southeast of the study area. Using a multi-linear regression technique on well logs and core data, permeability is estimated at well locations for flow unit characterization and flow capacity calculation. Results showed that five hydraulic flow units are identified through the studied wells, with relatively good correlation. Such correlation indicated a good continuity in the net pay zone of Abu Madi Formation in the Nile Delta reservoirs. The developed hydraulic flow units (HFUs) are classified according to its hydraulic conductivity into two main categories: the first category comprises the units with low permeability (K 1270 mD). The reservoir flow capacity (RFC) of these units indicated the development of 4 distinct classes (~11, ~30, ~80, and greater than 130 D.ft). The wells within the Northwestern part of the study area showed three HFUs that relatively vary from those located at the Southeast where two HFUs are only developed. In addition, the Southeastern part of the reservoir is characterized by good RFC as indicated by the development of high order HFUs (3, 4, and 5) compared to the Northeastern part with predominated low order HFUs (1, 2, and 3). Such results are crucial for the efficient field development and profound reservoir management of oil and gas fields in the Nile Delta.展开更多
We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by non-hydrostatic stress changes. We generate seismic models from coupled sim...We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by non-hydrostatic stress changes. We generate seismic models from coupled simulations to examine the relationship between reservoir geometry, stress path and seismic anisotropy. The results indicate that geometry influences the evolution of stress,which leads to stress-induced seismic anisotropy. Although stress anisotropy is high for the small reservoir, the effect of stress arching and the ability of the side-burden to support the excess load limit the overall change in effective stress and hence seismic anisotropy. For the extensive reservoir, stress anisotropy and induced seismic anisotropy are high. The extensive and elongate reservoirs experience significant compaction, where the inefficiency of the developed stress arching in the side-burden cannot support the excess load.The elongate reservoir displays significant stress asymmetry,with seismic anisotropy developing predominantly along the long-edge of the reservoir. We show that the link betweenstress path parameters and seismic anisotropy is complex,where the anisotropic symmetry is controlled not only by model geometry but also the nonlinear rock physics model used. Nevertheless, a workflow has been developed to model seismic anisotropy induced by non-hydrostatic stress changes, allowing field observations of anisotropy to be linked with geomechanical models.展开更多
The BZ19-6 gas field is characterized by high temperature and high pressure (HTHP), high condensate content, little difference between the formation pressure and dew point pressure, and large amount of reverse condens...The BZ19-6 gas field is characterized by high temperature and high pressure (HTHP), high condensate content, little difference between the formation pressure and dew point pressure, and large amount of reverse condensate liquid. During the early stage of depletion development, the production gas-oil ratio (GOR) and production capacity remain relatively stable, which is inconsistent with the conventional reverse condensate seepage law. In view of the static and dynamic conflict in development and production, indoor high-temperature and high-pressure PVT experiment was carried out to reveal the mist-like condensation phenomenon of fluids in the BZ19-6 formation. And the seepage characteristics of condensate gas reservoirs with various degrees of depletion under the condition of HTHP were analyzed based on production performance. The change rule of fluid phase state was analyzed in response to the characterization difficulties of the seepage mechanism. The fluid state was described using the miscible mechanism. And the interphase permeability interpolation coefficient was introduced based on interfacial tension. By doing so, the accurate characterization of the “single-phase flow of condensate gas-near-miscible mist-like quasi single-phase flow-oil-gas two-phase flow” during the development process was achieved. Then the accurate fitting of key indicators for oilfield development was completed, and the distribution law of formation pressure and the law of condensate oil precipitation under different reservoir conditions are obtained. Based on research results, the regulation strategy of variable flow rate production was developed. Currently, the work system has been optimized for 11 wells, achieving a “zero increase” in the GOS of the gas field and an annual oil increase of 22,000 cubic meters.展开更多
Dezfol embayment in the Southwest of Iran is located in the Zagros fold-thrust belt, which is one of the world’s largest petroleum provinces. Ilam Formation (Santonian-Companian) is one of the reservoir formations in...Dezfol embayment in the Southwest of Iran is located in the Zagros fold-thrust belt, which is one of the world’s largest petroleum provinces. Ilam Formation (Santonian-Companian) is one of the reservoir formations in this area that has been less studied. This paper focused on reservoir properties in this formation using petrography and petrophysics data. According to the petrography studies Ilam Formation composed of limestone as dominant lithology. Detailed petrographic analyses, have led to identification of 10 micro-facies which are represented as a carbonate ramp depositional model. Also petrographic analyses are revealed that cementation, dissolution, compaction and dolomitization are most important digenetic processes. Detailed petrographic analyses and petrophysics data showed that due to mud-supported nature of more facies (inherited low reservoir potential from their depositional settings), diagenetic process plays an important role in increasing of reservoir quality. However cementation and dissolution had negative and positive effects on Ilam reservoir formation, respectively. Finally at the end for better correlation and to create a flow unit, according to the petrography data and using petrophysics log, this reservoir is divided into 5 units (flow unite) by using Geolog software and then they have been correlated across the field.展开更多
Understanding the flow mechanisms between hydrocarbons and interfaces in nanopores is critical for fluid supply in tight reservoirs with huge reserves.In this paper,the nanoscale liquid-solid interface interaction pot...Understanding the flow mechanisms between hydrocarbons and interfaces in nanopores is critical for fluid supply in tight reservoirs with huge reserves.In this paper,the nanoscale liquid-solid interface interaction potential is analyzed based on the molecular interface theory,and a new nanoscale fluid viscosity model is constructed through the Eyring model,and the fluid velocity and flow flux models in nanopores are derived based on the liquid-solid interface slip condition.In addition,n-pentane flow characteristics in quartz nanopores were investigated with key parameters including:the Hamaker constant,the decay length,the wetting angle,the boundary slip and the flux coefficient.The proposed model is validated in a comparison of theory,simulation and laboratory results.The study results show:(1)influenced by the liquid-solid interfacial effect,there is a viscosity gap between the fluid in the bulk and at the boundary,resulting in a non-linear variation of the flow velocity.Of the multiple microscopic forces considered by the model,Ligshitz-Van der Waals force has the strongest effect in confined pores below 40 nm,and electrostatic force has the weakest effect.When the pore diameter less than 10 nm,the constrained fluid viscosity was improved above 4 times.(2)based on the microscopic liquid-solid interface slip condition,a constrained space velocity model is derived,which indicates that the flow is directly dependent on the effective shear stresses on the fluid and the strength of the liquid-solid interface effect.Under the low shear stress in a tight reservoir,the slip at the liquid-solid interface has obvious linear characteristics,and the slip velocity depends on the effective shear stress.The liquid-solid interfacial effect parameter is increased from 1 to 30,and the slip velocity is reduced to 3.2Å/ps,which is a 55%reduction.(3)in this paper,the hamaker constant of n-pentane-quartz interface based on the molecular spacing variation and the decay constant for different water types and solute concentrations are obtained,and the effect of the decay length on the flow coefficient of the nano confined flow model is explored for different pore radiuses.The flux coefficient increases with pore radius,and the effect of the decay length is greater for pores<100 nm.展开更多
为探究流域内物源的空间分布状态对泥石流易发性的影响,采用数学统计原理最近邻指数对物源的空间聚类进行量化,并基于2243条小流域为评价单元,以纵比降、面积-高程积分、地形湿度指数、地震峰值加速度、岩性坚硬度为孕灾指标,物源的聚...为探究流域内物源的空间分布状态对泥石流易发性的影响,采用数学统计原理最近邻指数对物源的空间聚类进行量化,并基于2243条小流域为评价单元,以纵比降、面积-高程积分、地形湿度指数、地震峰值加速度、岩性坚硬度为孕灾指标,物源的聚集度指标、连通性指数、物源储量等物源指标为核心,依托LightGBM模型探究金沙江上游石鼓-岗托河段的泥石流易发性。研究过程分别计算物源因子的指标体系与不包含物源因子的指标体系。两种结果均表明:较高、高易发区主要集中在奔子栏-巴塘河段。通过ROC(receiver operating characteristic curve)曲线分析可得,加入物源特征指标后得出AUC(area under the curve)值与不含物源特征的AUC值相比提升了6%,表明在加入物源指标后,模型呈现出良好表现,预测精度较高;也证明了物源特征指标对于泥石流发生概率的关联性很大。展开更多
文摘Tetrahydrofuran（THF） was selected as the substitute to study the flow behaviors and the mechanism of the hydrates blockage in pipelines.The slurrylike hydrates and slushlike hydrates are observed with the formation of hydrates in pipeline.There is a critical hydrate volume concentration of 50.6% for THF slurries and pipeline will be free of hydrate blockage while the hydrate volume concentration is lower than the critical volume concentration;otherwise,pipeline will be easy to be blocked.Fully turbulent flow occurs and friction factors tend to be constant when the velocity reaches 1.5 m/s.And then,constant values of friction factors that depend on the volume concentrations in the slurry were regressed to estimate the pressure drops of THF hydrate slurry at large mean velocity.Finally,a safe region,defined according to the critical hydrate volume concentration,was proposed for THF hydrate slurry,which may provide some insight for further studying the natural gas hydrate slurries and judge whether the pipeline can be run safely or not.
基金This project is supported by National Natural Science Foundation of China (No.50275089)
文摘The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and the simulation is carried out by using finite difference method. The results show that the lubricant flow status and end leakage quantity are greatly influenced by spiral angle,and that the rotating speed has little influence on the flow status. With advisable geometry design, the separation of lubricant between different oil wedges can be obtained, which can decrease the temperature rise effectively.
基金Supported by the Key Program of the National Natural Science Foundation of China under Grant No 61334009the National High Technology Research and Development Program of China under Grant No 2014AA032604
文摘CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.
基金Funded by the New Product Research Program(No.X18ECQ0A00)of Baoshan Iron&Steel Co.Ltd.
文摘In order to study the high temperature flow behaviour of the V modified 2.25Cr-1Mo steel plate to guide the industrial rolling practice, the hot compression tests were carried out at the temperatures from 900 ℃ to 1150 ℃ and the strain rates from 0.01s^-1 to 1 s^-1 on Thermecmastor-Z equipment. Based on the experimental data of the hot compression tests, a kind of Arrhenius-type constitutive equation was developed.The equation can accurately show the relationship between the flow stress and the deformation temperature, the strain and the strain rate. The measured true stress-true strain curves exhibit two kinds of flow stress curves. Moreover, the forming mechanisms of these two types curves were explained by softening, wok hardening theory as well as metallographic and hardness experimental results. The accuracy of the developed Arrheniustype constitutive equation was identified by three kinds of statistic parameters and also by comparison of the measured and predicted data. The reasonable value of the three types of statistic parameters and the good agreement between the experimental and predicted data can confirm the validity of the developed Arrheniustype constitutive equation for V modified 2.25 Cr-1 Mo heat resistant steel plate.
文摘Field development typically requires detailed petrophysical analysis and well defined hydraulic flow units for comprehensive formation evaluation and reservoir characterization. In the present study, pay zones petrophysics are studied using an assembly of well log data from 8 wells together with core plugs measurements. Petrophysical analysis showed a good reservoir quality with average water saturation increasing toward the East and Southeast of the study area. Using a multi-linear regression technique on well logs and core data, permeability is estimated at well locations for flow unit characterization and flow capacity calculation. Results showed that five hydraulic flow units are identified through the studied wells, with relatively good correlation. Such correlation indicated a good continuity in the net pay zone of Abu Madi Formation in the Nile Delta reservoirs. The developed hydraulic flow units (HFUs) are classified according to its hydraulic conductivity into two main categories: the first category comprises the units with low permeability (K 1270 mD). The reservoir flow capacity (RFC) of these units indicated the development of 4 distinct classes (~11, ~30, ~80, and greater than 130 D.ft). The wells within the Northwestern part of the study area showed three HFUs that relatively vary from those located at the Southeast where two HFUs are only developed. In addition, the Southeastern part of the reservoir is characterized by good RFC as indicated by the development of high order HFUs (3, 4, and 5) compared to the Northeastern part with predominated low order HFUs (1, 2, and 3). Such results are crucial for the efficient field development and profound reservoir management of oil and gas fields in the Nile Delta.
基金the sponsors of the IPEGG project, BG, BP, Statoilthe Research Council UK (EP/K035878/1+1 种基金 EP/K021869/1 NE/L000423/1) for financial support
文摘We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by non-hydrostatic stress changes. We generate seismic models from coupled simulations to examine the relationship between reservoir geometry, stress path and seismic anisotropy. The results indicate that geometry influences the evolution of stress,which leads to stress-induced seismic anisotropy. Although stress anisotropy is high for the small reservoir, the effect of stress arching and the ability of the side-burden to support the excess load limit the overall change in effective stress and hence seismic anisotropy. For the extensive reservoir, stress anisotropy and induced seismic anisotropy are high. The extensive and elongate reservoirs experience significant compaction, where the inefficiency of the developed stress arching in the side-burden cannot support the excess load.The elongate reservoir displays significant stress asymmetry,with seismic anisotropy developing predominantly along the long-edge of the reservoir. We show that the link betweenstress path parameters and seismic anisotropy is complex,where the anisotropic symmetry is controlled not only by model geometry but also the nonlinear rock physics model used. Nevertheless, a workflow has been developed to model seismic anisotropy induced by non-hydrostatic stress changes, allowing field observations of anisotropy to be linked with geomechanical models.
文摘The BZ19-6 gas field is characterized by high temperature and high pressure (HTHP), high condensate content, little difference between the formation pressure and dew point pressure, and large amount of reverse condensate liquid. During the early stage of depletion development, the production gas-oil ratio (GOR) and production capacity remain relatively stable, which is inconsistent with the conventional reverse condensate seepage law. In view of the static and dynamic conflict in development and production, indoor high-temperature and high-pressure PVT experiment was carried out to reveal the mist-like condensation phenomenon of fluids in the BZ19-6 formation. And the seepage characteristics of condensate gas reservoirs with various degrees of depletion under the condition of HTHP were analyzed based on production performance. The change rule of fluid phase state was analyzed in response to the characterization difficulties of the seepage mechanism. The fluid state was described using the miscible mechanism. And the interphase permeability interpolation coefficient was introduced based on interfacial tension. By doing so, the accurate characterization of the “single-phase flow of condensate gas-near-miscible mist-like quasi single-phase flow-oil-gas two-phase flow” during the development process was achieved. Then the accurate fitting of key indicators for oilfield development was completed, and the distribution law of formation pressure and the law of condensate oil precipitation under different reservoir conditions are obtained. Based on research results, the regulation strategy of variable flow rate production was developed. Currently, the work system has been optimized for 11 wells, achieving a “zero increase” in the GOS of the gas field and an annual oil increase of 22,000 cubic meters.
文摘Dezfol embayment in the Southwest of Iran is located in the Zagros fold-thrust belt, which is one of the world’s largest petroleum provinces. Ilam Formation (Santonian-Companian) is one of the reservoir formations in this area that has been less studied. This paper focused on reservoir properties in this formation using petrography and petrophysics data. According to the petrography studies Ilam Formation composed of limestone as dominant lithology. Detailed petrographic analyses, have led to identification of 10 micro-facies which are represented as a carbonate ramp depositional model. Also petrographic analyses are revealed that cementation, dissolution, compaction and dolomitization are most important digenetic processes. Detailed petrographic analyses and petrophysics data showed that due to mud-supported nature of more facies (inherited low reservoir potential from their depositional settings), diagenetic process plays an important role in increasing of reservoir quality. However cementation and dissolution had negative and positive effects on Ilam reservoir formation, respectively. Finally at the end for better correlation and to create a flow unit, according to the petrography data and using petrophysics log, this reservoir is divided into 5 units (flow unite) by using Geolog software and then they have been correlated across the field.
基金supported by the Key Program of the National Natural Science Foundation of China[No.U24B200683]Natural Science Foundation of Sichuan Provincial,China[No.2024NSFSC2012].
文摘Understanding the flow mechanisms between hydrocarbons and interfaces in nanopores is critical for fluid supply in tight reservoirs with huge reserves.In this paper,the nanoscale liquid-solid interface interaction potential is analyzed based on the molecular interface theory,and a new nanoscale fluid viscosity model is constructed through the Eyring model,and the fluid velocity and flow flux models in nanopores are derived based on the liquid-solid interface slip condition.In addition,n-pentane flow characteristics in quartz nanopores were investigated with key parameters including:the Hamaker constant,the decay length,the wetting angle,the boundary slip and the flux coefficient.The proposed model is validated in a comparison of theory,simulation and laboratory results.The study results show:(1)influenced by the liquid-solid interfacial effect,there is a viscosity gap between the fluid in the bulk and at the boundary,resulting in a non-linear variation of the flow velocity.Of the multiple microscopic forces considered by the model,Ligshitz-Van der Waals force has the strongest effect in confined pores below 40 nm,and electrostatic force has the weakest effect.When the pore diameter less than 10 nm,the constrained fluid viscosity was improved above 4 times.(2)based on the microscopic liquid-solid interface slip condition,a constrained space velocity model is derived,which indicates that the flow is directly dependent on the effective shear stresses on the fluid and the strength of the liquid-solid interface effect.Under the low shear stress in a tight reservoir,the slip at the liquid-solid interface has obvious linear characteristics,and the slip velocity depends on the effective shear stress.The liquid-solid interfacial effect parameter is increased from 1 to 30,and the slip velocity is reduced to 3.2Å/ps,which is a 55%reduction.(3)in this paper,the hamaker constant of n-pentane-quartz interface based on the molecular spacing variation and the decay constant for different water types and solute concentrations are obtained,and the effect of the decay length on the flow coefficient of the nano confined flow model is explored for different pore radiuses.The flux coefficient increases with pore radius,and the effect of the decay length is greater for pores<100 nm.
文摘为探究流域内物源的空间分布状态对泥石流易发性的影响,采用数学统计原理最近邻指数对物源的空间聚类进行量化,并基于2243条小流域为评价单元,以纵比降、面积-高程积分、地形湿度指数、地震峰值加速度、岩性坚硬度为孕灾指标,物源的聚集度指标、连通性指数、物源储量等物源指标为核心,依托LightGBM模型探究金沙江上游石鼓-岗托河段的泥石流易发性。研究过程分别计算物源因子的指标体系与不包含物源因子的指标体系。两种结果均表明:较高、高易发区主要集中在奔子栏-巴塘河段。通过ROC(receiver operating characteristic curve)曲线分析可得,加入物源特征指标后得出AUC(area under the curve)值与不含物源特征的AUC值相比提升了6%,表明在加入物源指标后,模型呈现出良好表现,预测精度较高;也证明了物源特征指标对于泥石流发生概率的关联性很大。
