CO_(2)enhanced oil recovery plays an important role in carbon storage and utilization.However,the incomplete understanding of the underlying microscopic convection–diffusion mechanisms in complex pore structures has ...CO_(2)enhanced oil recovery plays an important role in carbon storage and utilization.However,the incomplete understanding of the underlying microscopic convection–diffusion mechanisms in complex pore structures has constrained the broader industrial application of CO_(2)geo-sequestration.This work develops a pore-scale numerical model considering molecular convection–diffusion to investigate CO_(2)-oil miscible displacement in two-and three-dimensional porous structures of conglomerate rocks.The effects of CO_(2)injection rates and pore structure properties on convection–diffusion are analyzed.By reconstructing the distribution of unexploited pores,the CO_(2)sweep efficiency is quantitatively evaluated.Furthermore,a sequestration factor is proposed to evaluate the CO_(2)storage capacity during miscible displacement.Convection significantly enhances the CO_(2)mass fraction in fractures with high flow rates.Subsequently,CO_(2)gradually diffuses into matrix pores without velocity distribution.Both convection and diffusion contribute to improving CO_(2)displacement efficiency.Diffusion facilitates the dissolution of CO_(2)into oil within small-diameter pores,and convection effectively mobilizes oil in large pore bodies.Developed and homogeneous pore structures enhance CO_(2)displacement efficiency,whereas CO_(2)flows along the main flow channels in heterogeneous pore structures,resulting in lower displacement efficiency.Diffusion plays a crucial role in CO_(2)storage within porous media.At low injection rates,dissolved CO_(2)is trapped in poorly connected and blind-end pores.The injection rate is negatively correlated with the sequestration factor.展开更多
As one promising CO_(2)capture,utilization and storage(CCUS)technology,miscible CO_(2)-enhanced oil recovery(CO_(2)-EOR)significantly outperforms immiscible flooding in enhancing oil production and storing CO_(2).Howe...As one promising CO_(2)capture,utilization and storage(CCUS)technology,miscible CO_(2)-enhanced oil recovery(CO_(2)-EOR)significantly outperforms immiscible flooding in enhancing oil production and storing CO_(2).However,achieving CO_(2)miscible flooding is often hindered by the high minimum miscibility pressure of CO_(2)-oil system in many reservoirs.To address this issue,this study focuses on the mechanisms for enhancing CO_(2)-oil miscibility using different types of surfactants and their blends with ethanol.The effects of fatty alcohol polyoxyethylene ethers(EO),fatty alcohol polyoxypropylene ethers(PO),tributyl citrate(TC),and glyceryl triacetate(GT)on the CO_(2)-oil miscibility pressure are quantitatively analyzed,as well as their synergy with ethanol.Results demonstrated that all tested surfactant additives reduce the CO_(2)-oil miscibility pressu re.For ethe r-based surfactant additives,an increase in the degree of polymerization(CO_(2)-philic groups)weakens the effectiveness to reduce miscibility pressure.Oxygen atoms in the functional group contribute more significantly to miscibility enhancement than carbon atoms.Among ester surfactants,GT achieved the best reduction effect of miscibility pressure(11.82%at 3.0 wt%),attributed to its symmetrical short side-chain structure and ester groups.Furthermore,ethanol exhibited a significant improvement for surfactants in enhancing miscibility.Notably,the reduction of CO_(2)-oil miscibility pressure increases to 27.9%by 3.0 wt%GT blended with 5.0 wt%ethanol.These findings demonstrate that blending surfactants with ethanol is a feasible and effective strategy to facilitate miscible CO_(2)flooding.This study provides valuable insights and practical guidance for the field implementation of miscible CO_(2)-EOR.展开更多
According to the research theory of improved black oil simulator, a practical mathematical model for CO2 miscible flooding was presented. In the model, the miscible process simulation was realized by adjusting oil/gas...According to the research theory of improved black oil simulator, a practical mathematical model for CO2 miscible flooding was presented. In the model, the miscible process simulation was realized by adjusting oil/gas relative permeability and effective viscosity under the condition of miscible flow. In order to predict the production performance（fast,） streamline method is employed to solve this model as an alternative to traditional finite（difference） （methods.） Based on streamline distribution of steady-state flow through porous media with complex boundary confirmed with the boundary element method （BEM）, an explicit total variation diminishing （TVD） method is used to solve the one-dimensional flow problem. At the same time, influences of development scheme, solvent slug size, and injection periods on CO2 drive recovery are discussed. The model has the advantages of less（information） need, fast calculation, and adaptation to calculate CO2 drive performance of all kinds of patterns in a random shaped porous media with assembly boundary. It can be an（effective） tool for early stage screening and reservoir dynamic management of the CO2（miscible） oil field.展开更多
The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and opti...The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.展开更多
In this paper, melt blends of poly（propylene carbonate） （PPC） with poly（butylene succinate） （PBS） were characterized by dynamic mechanical analysis （DMA）, differential scanning calorimetry （DSC）, tensile t...In this paper, melt blends of poly（propylene carbonate） （PPC） with poly（butylene succinate） （PBS） were characterized by dynamic mechanical analysis （DMA）, differential scanning calorimetry （DSC）, tensile testing, wide-angle X-ray diffraction （WAXD）, polarized optical microscopy and thermogravimetric analysis （TGA）. The results indicated that the glass transition temperature of PPC in the 90/10 PPC/PBS blend was decreased by about 11 K comparing with that of pure PPC. The presence of 10% PBS was partially miscible with PPC. The 90/10 PPC/PBS blend had better impact and tensile strength than those of the other PPC/PBS blends. The glass transition temperature of PPC in the 80/20, 70/30, and 60/40 PPC/PBS blends was improved by about 4.9 K, 4.2 K, and 13 K comparing with that of pure PPC, respectively; which indicated the immiscibility between PPC and PBS. The DSC results indicated that the crystallization of PBS became more difficult when the PPC content increased. The matrix of PPC hindered the crystallization process of PBS. While the content of PBS was above 20%, significant crystallization-induced phase separation was observed by polarized optical microscopy. It was found from the WAXD analysis that the crystal structure of PBS did not change, and the degree of crystallinity increased with increasing PBS content in the PPC/PBS blends.展开更多
Liquid crystalline polymer-polyamide 66 (LCP/PA66) blends were compounded by using a Brabender mixing followed by compression moulding. The LCP employed was a semi-flexible liquid crystalline copolyesteramide based o...Liquid crystalline polymer-polyamide 66 (LCP/PA66) blends were compounded by using a Brabender mixing followed by compression moulding. The LCP employed was a semi-flexible liquid crystalline copolyesteramide based on 30% (molar fraction ) of p-amino benzoic acid (ABA ) and 70% (molar fraction) of poly (ethylene terephthalate) (PET). The LCP/PA66 blends were investigated in terms of the thermal and dynamic mechanical properties. It was found that PA66 and LCP components of the blends are miscible in the molten state, but are partially miscible in the solid state. The inclusion of the semi-flexible LCP into PA66 retards the crystallization rate of PA66. Furthermore, the melting temperature and the degree of crystallinity of PA66 are reduced considerably due to the LCP addition.展开更多
A modification of a finite element method of Douglas and Roberts for approximating the solution of the equations describing compressible miscible displacement in a porous medium is proposed and analyzed. The pressure ...A modification of a finite element method of Douglas and Roberts for approximating the solution of the equations describing compressible miscible displacement in a porous medium is proposed and analyzed. The pressure is treated by a parabolic mixed finite element method using a Raviart-Thomas space of index rover a quasiregular partition, An extension of the Darcy velocity along Gauss lines is used in the evaluation of the coefficients in the Galerkin procedure for the concentration. A simple computational procedure allows the superconvergence property of the fluid velocity to be retained in our total algorithm.展开更多
An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve misc...An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO_2,which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO_2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen(N_2), methane(C_1), ethane(C_2) and propane(C_3) on CO_2 MMP. The simulation results reveal that,as an impurity, nitrogen increases CO_2–oil MMP more so than methane. On the other hand, increasing the propane(C_3)content can lead to a significant decrease in CO_2 MMP, whereas varying the concentrations of ethane(C_2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO_2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available.展开更多
A model has been developed to describe the microstructure evolution in the atomized droplets of Cu-Fe alloy during cooling through the metastable miscibility gap. Calculations have been performed for Cu85Fe15 alloy to...A model has been developed to describe the microstructure evolution in the atomized droplets of Cu-Fe alloy during cooling through the metastable miscibility gap. Calculations have been performed for Cu85Fe15 alloy to investigate the process of liquid-liquid phase transformation. The numerical results indicate that the minority phase droplets are nucleated in a temperature region around the peak of the supersaturation. The average radius of the Fe-rlch droplets decreases and the number density of the minority phase droplets increases with decreasing the atomized droplet size. The simulated results were compared with the experimental ones. The kinetic process of the liquid-liquid phase transformation was discussed in detail.展开更多
An efficient time stepping procedure is proposed to treat the system describing compressible miscible displacement in a porous medium by employing a mixed finite element method to approximate the pressure and the flui...An efficient time stepping procedure is proposed to treat the system describing compressible miscible displacement in a porous medium by employing a mixed finite element method to approximate the pressure and the fluid velocity and a standard Galerkin method to approximate the concentration. An extension of the Darcy velocity along Gauss lines is used in the evaluation of the coefficients in the Galerkin procedure for the concentration. These results show that the total algorithm has the superconvergence property of the fluid velocity.展开更多
In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction par...In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.展开更多
The miscible displacement of one incompressible fluid by another in a porous medium is considered in this paper. The concentration is split in a first-order hyberbolic equation and a homogeneous parabolic equation wit...The miscible displacement of one incompressible fluid by another in a porous medium is considered in this paper. The concentration is split in a first-order hyberbolic equation and a homogeneous parabolic equation within each lime step. The pressure and Us velocity field is computed by a mixed finite element method. Optimal order estimates are derived for the no diffusion case and the diffusion case.展开更多
The influence of solvent on the miscibility of polystyrene（PS） and poly（styrene-co-acrylonitrile）（PSAN） blends has been investigated viscometrically. The miscibility of different PS/PSAN blend（30/70, 50/50 and ...The influence of solvent on the miscibility of polystyrene（PS） and poly（styrene-co-acrylonitrile）（PSAN） blends has been investigated viscometrically. The miscibility of different PS/PSAN blend（30/70, 50/50 and 70/30） compositions in acetone and benzene at 20, 30, and 40 °C was investigated on the basis of the sign of Chee（ΔB and ）, and Sun’s（α） criteria. The values of these parameters were evaluated from the analyses of reduced viscosity data of binary（solvent/polymer） and ternary（solvent/polymer1/polymer2） polymer systems. These investigations indicated partial miscibility for both the blend systems. However, PS/PSAN/acetone blend system showed somewhat higher partial miscibility than the PS/PSAN/Benzene blend system highlighting the impact of solvent over the polymer-polymer interactions and hence their miscibility. The results obtained through viscometry were also corroborated by the refractive index and density results for the blends under study. The effect of temperature on miscibility in both the cases was almost negligible.展开更多
The purpose of this study is to optimize the existing carbon dioxide （CO2） flood in deep dolomite formations by improving oil sweep efficiency of miscible CO2 floods and enhancing the conformance control. A full com...The purpose of this study is to optimize the existing carbon dioxide （CO2） flood in deep dolomite formations by improving oil sweep efficiency of miscible CO2 floods and enhancing the conformance control. A full compositional simulation model using a detailed geologic characterization was built to optimize the injection pattern. The model is a quarter of an inverted nine-spot and covers 20 acres of field formation. Geologic description was used to construct the simulation grids. The simulation layers represent actual flow units and resemble the large variation of reservoir properties. History match was performed to validate the model. Several sensitivity runs were made to improve the CO2 sweep efficiency and increase the oil recovery. Finally, the optimum CO2 injection rate for dolomite formations was determined approximately. Simulation results also indicate that a water-alternating-gas （WAG） ratio of 1：1 along with an ultimate CO2 slug of 100% hydrocarbon pore volume （HCPV） will allow an incremental oil recovery of 18%. The additional recovery increases to 34% if a polymer is injected as a conformance control agent during the course of the WAG process at a ratio of 1：1. According to the results, a pattern reconfiguration change from the nine spot to staggered line drive would represent an incremental oil recovery of 26%.展开更多
Miscibility, isothermal crystallization kinetics, and morphology of poly（L-lactide）/poly（trimethylene carbonate） （PLLA/PTMC） crystalline/amorphous blends were studied by differential scanning calorimetry （DSC）...Miscibility, isothermal crystallization kinetics, and morphology of poly（L-lactide）/poly（trimethylene carbonate） （PLLA/PTMC） crystalline/amorphous blends were studied by differential scanning calorimetry （DSC） and optical microscopy （OM）. The heterogeneity of OM images and an unchanged glass transition temperature showed that PLLA was immiscible with PTMC. During isothermal crystallization, the crystallization rate of PLLA improved when the PTMC content was low （≤ 20%）. However, when the PTMC content was high （≥ 30%）, the crystallization rate decreased significantly. The reason of these nonlinear changes in crystal kinetics was analyzed according to the nucleation and growth process by virtue of a microscope heating stage. The isothermal crystallization morphologies of the blends were also studied by polarized optical microscopy and the results confirmed the conclusions obtained from crystallization kinetics.展开更多
Positron annihilation spectroscopy(PAS)was utilized to investigate the relationship between the free-volume hole properties and miscibility of dynamically vulcanized EPDM/PP blend.The results showed that the noncrysta...Positron annihilation spectroscopy(PAS)was utilized to investigate the relationship between the free-volume hole properties and miscibility of dynamically vulcanized EPDM/PP blend.The results showed that the noncrystalline region of PP and EPDM in the blend was partially miscible and the miscibility of the blend became worse when the weight percent of EPDM was<50%.This was also demonstrated by DMTA and mechanical properties of the blends with various compositions.展开更多
基金supported by National Natural Science Foundation of China(42172159,52404048)China Postdoctoral Science Foundation(2023M743870)+1 种基金Postdoctoral Fellowship Program of CPSF(GZB20230864)Frontier Interdisciplinary Exploration Research Program of China University of Petroleum,Beijing(2462024XKQY002).
文摘CO_(2)enhanced oil recovery plays an important role in carbon storage and utilization.However,the incomplete understanding of the underlying microscopic convection–diffusion mechanisms in complex pore structures has constrained the broader industrial application of CO_(2)geo-sequestration.This work develops a pore-scale numerical model considering molecular convection–diffusion to investigate CO_(2)-oil miscible displacement in two-and three-dimensional porous structures of conglomerate rocks.The effects of CO_(2)injection rates and pore structure properties on convection–diffusion are analyzed.By reconstructing the distribution of unexploited pores,the CO_(2)sweep efficiency is quantitatively evaluated.Furthermore,a sequestration factor is proposed to evaluate the CO_(2)storage capacity during miscible displacement.Convection significantly enhances the CO_(2)mass fraction in fractures with high flow rates.Subsequently,CO_(2)gradually diffuses into matrix pores without velocity distribution.Both convection and diffusion contribute to improving CO_(2)displacement efficiency.Diffusion facilitates the dissolution of CO_(2)into oil within small-diameter pores,and convection effectively mobilizes oil in large pore bodies.Developed and homogeneous pore structures enhance CO_(2)displacement efficiency,whereas CO_(2)flows along the main flow channels in heterogeneous pore structures,resulting in lower displacement efficiency.Diffusion plays a crucial role in CO_(2)storage within porous media.At low injection rates,dissolved CO_(2)is trapped in poorly connected and blind-end pores.The injection rate is negatively correlated with the sequestration factor.
基金supported by the National Natural Science Foundation of China(52374063,52204065 and 52304098)the Shandong Provincial Natural Science Foundation(ZR2023ME049)+2 种基金the Fundamental Research Funds for the Central Universities(25CX07004A)State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering(SDGZK2429)Shenzhen Science and Technology Program(JCYJ20220818095605012)。
文摘As one promising CO_(2)capture,utilization and storage(CCUS)technology,miscible CO_(2)-enhanced oil recovery(CO_(2)-EOR)significantly outperforms immiscible flooding in enhancing oil production and storing CO_(2).However,achieving CO_(2)miscible flooding is often hindered by the high minimum miscibility pressure of CO_(2)-oil system in many reservoirs.To address this issue,this study focuses on the mechanisms for enhancing CO_(2)-oil miscibility using different types of surfactants and their blends with ethanol.The effects of fatty alcohol polyoxyethylene ethers(EO),fatty alcohol polyoxypropylene ethers(PO),tributyl citrate(TC),and glyceryl triacetate(GT)on the CO_(2)-oil miscibility pressure are quantitatively analyzed,as well as their synergy with ethanol.Results demonstrated that all tested surfactant additives reduce the CO_(2)-oil miscibility pressu re.For ethe r-based surfactant additives,an increase in the degree of polymerization(CO_(2)-philic groups)weakens the effectiveness to reduce miscibility pressure.Oxygen atoms in the functional group contribute more significantly to miscibility enhancement than carbon atoms.Among ester surfactants,GT achieved the best reduction effect of miscibility pressure(11.82%at 3.0 wt%),attributed to its symmetrical short side-chain structure and ester groups.Furthermore,ethanol exhibited a significant improvement for surfactants in enhancing miscibility.Notably,the reduction of CO_(2)-oil miscibility pressure increases to 27.9%by 3.0 wt%GT blended with 5.0 wt%ethanol.These findings demonstrate that blending surfactants with ethanol is a feasible and effective strategy to facilitate miscible CO_(2)flooding.This study provides valuable insights and practical guidance for the field implementation of miscible CO_(2)-EOR.
文摘According to the research theory of improved black oil simulator, a practical mathematical model for CO2 miscible flooding was presented. In the model, the miscible process simulation was realized by adjusting oil/gas relative permeability and effective viscosity under the condition of miscible flow. In order to predict the production performance（fast,） streamline method is employed to solve this model as an alternative to traditional finite（difference） （methods.） Based on streamline distribution of steady-state flow through porous media with complex boundary confirmed with the boundary element method （BEM）, an explicit total variation diminishing （TVD） method is used to solve the one-dimensional flow problem. At the same time, influences of development scheme, solvent slug size, and injection periods on CO2 drive recovery are discussed. The model has the advantages of less（information） need, fast calculation, and adaptation to calculate CO2 drive performance of all kinds of patterns in a random shaped porous media with assembly boundary. It can be an（effective） tool for early stage screening and reservoir dynamic management of the CO2（miscible） oil field.
基金ACKNOWLEDGMENT This work was supported by the Key Science Foundation of Education Ministry of China and the Anhui Science Foundation.
文摘The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.
基金This work was supported by the National Natural Science Foundation of China(Nos.270274049 and 220374051).
文摘In this paper, melt blends of poly（propylene carbonate） （PPC） with poly（butylene succinate） （PBS） were characterized by dynamic mechanical analysis （DMA）, differential scanning calorimetry （DSC）, tensile testing, wide-angle X-ray diffraction （WAXD）, polarized optical microscopy and thermogravimetric analysis （TGA）. The results indicated that the glass transition temperature of PPC in the 90/10 PPC/PBS blend was decreased by about 11 K comparing with that of pure PPC. The presence of 10% PBS was partially miscible with PPC. The 90/10 PPC/PBS blend had better impact and tensile strength than those of the other PPC/PBS blends. The glass transition temperature of PPC in the 80/20, 70/30, and 60/40 PPC/PBS blends was improved by about 4.9 K, 4.2 K, and 13 K comparing with that of pure PPC, respectively; which indicated the immiscibility between PPC and PBS. The DSC results indicated that the crystallization of PBS became more difficult when the PPC content increased. The matrix of PPC hindered the crystallization process of PBS. While the content of PBS was above 20%, significant crystallization-induced phase separation was observed by polarized optical microscopy. It was found from the WAXD analysis that the crystal structure of PBS did not change, and the degree of crystallinity increased with increasing PBS content in the PPC/PBS blends.
基金Supported by the National Natural Science Foundation of China.
文摘Liquid crystalline polymer-polyamide 66 (LCP/PA66) blends were compounded by using a Brabender mixing followed by compression moulding. The LCP employed was a semi-flexible liquid crystalline copolyesteramide based on 30% (molar fraction ) of p-amino benzoic acid (ABA ) and 70% (molar fraction) of poly (ethylene terephthalate) (PET). The LCP/PA66 blends were investigated in terms of the thermal and dynamic mechanical properties. It was found that PA66 and LCP components of the blends are miscible in the molten state, but are partially miscible in the solid state. The inclusion of the semi-flexible LCP into PA66 retards the crystallization rate of PA66. Furthermore, the melting temperature and the degree of crystallinity of PA66 are reduced considerably due to the LCP addition.
基金Supported by China State Major Rey Project for Basic Researches
文摘A modification of a finite element method of Douglas and Roberts for approximating the solution of the equations describing compressible miscible displacement in a porous medium is proposed and analyzed. The pressure is treated by a parabolic mixed finite element method using a Raviart-Thomas space of index rover a quasiregular partition, An extension of the Darcy velocity along Gauss lines is used in the evaluation of the coefficients in the Galerkin procedure for the concentration. A simple computational procedure allows the superconvergence property of the fluid velocity to be retained in our total algorithm.
文摘An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO_2,which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO_2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen(N_2), methane(C_1), ethane(C_2) and propane(C_3) on CO_2 MMP. The simulation results reveal that,as an impurity, nitrogen increases CO_2–oil MMP more so than methane. On the other hand, increasing the propane(C_3)content can lead to a significant decrease in CO_2 MMP, whereas varying the concentrations of ethane(C_2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO_2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available.
基金the finan cial supports from the National Natural Science Foundation of China(Grant Nos.50271076,50371092 , 50395104)the Sino-Germany Science Foundation(GZ032/1) the Natural Science Foundation of Liaoning Province of China.
文摘A model has been developed to describe the microstructure evolution in the atomized droplets of Cu-Fe alloy during cooling through the metastable miscibility gap. Calculations have been performed for Cu85Fe15 alloy to investigate the process of liquid-liquid phase transformation. The numerical results indicate that the minority phase droplets are nucleated in a temperature region around the peak of the supersaturation. The average radius of the Fe-rlch droplets decreases and the number density of the minority phase droplets increases with decreasing the atomized droplet size. The simulated results were compared with the experimental ones. The kinetic process of the liquid-liquid phase transformation was discussed in detail.
文摘An efficient time stepping procedure is proposed to treat the system describing compressible miscible displacement in a porous medium by employing a mixed finite element method to approximate the pressure and the fluid velocity and a standard Galerkin method to approximate the concentration. An extension of the Darcy velocity along Gauss lines is used in the evaluation of the coefficients in the Galerkin procedure for the concentration. These results show that the total algorithm has the superconvergence property of the fluid velocity.
基金The subject supported by National Natural Science Foundation of China
文摘In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.
基金This work was supported by China State Major Key Project for Basic Researches.
文摘The miscible displacement of one incompressible fluid by another in a porous medium is considered in this paper. The concentration is split in a first-order hyberbolic equation and a homogeneous parabolic equation within each lime step. The pressure and Us velocity field is computed by a mixed finite element method. Optimal order estimates are derived for the no diffusion case and the diffusion case.
基金supported by the Higher Education Commission,Islamabad,Pakistan in the form of an Indigenous PhD Fellowship Phase-IV to Zafarullah Khan Marwat.Zafarullah Khan Marwat is also grateful to the Higher Education Department(Colleges)Peshawar Khyber Pakhtunkhwa for grant of study leave for PhD Studies
文摘The influence of solvent on the miscibility of polystyrene（PS） and poly（styrene-co-acrylonitrile）（PSAN） blends has been investigated viscometrically. The miscibility of different PS/PSAN blend（30/70, 50/50 and 70/30） compositions in acetone and benzene at 20, 30, and 40 °C was investigated on the basis of the sign of Chee（ΔB and ）, and Sun’s（α） criteria. The values of these parameters were evaluated from the analyses of reduced viscosity data of binary（solvent/polymer） and ternary（solvent/polymer1/polymer2） polymer systems. These investigations indicated partial miscibility for both the blend systems. However, PS/PSAN/acetone blend system showed somewhat higher partial miscibility than the PS/PSAN/Benzene blend system highlighting the impact of solvent over the polymer-polymer interactions and hence their miscibility. The results obtained through viscometry were also corroborated by the refractive index and density results for the blends under study. The effect of temperature on miscibility in both the cases was almost negligible.
文摘The purpose of this study is to optimize the existing carbon dioxide （CO2） flood in deep dolomite formations by improving oil sweep efficiency of miscible CO2 floods and enhancing the conformance control. A full compositional simulation model using a detailed geologic characterization was built to optimize the injection pattern. The model is a quarter of an inverted nine-spot and covers 20 acres of field formation. Geologic description was used to construct the simulation grids. The simulation layers represent actual flow units and resemble the large variation of reservoir properties. History match was performed to validate the model. Several sensitivity runs were made to improve the CO2 sweep efficiency and increase the oil recovery. Finally, the optimum CO2 injection rate for dolomite formations was determined approximately. Simulation results also indicate that a water-alternating-gas （WAG） ratio of 1：1 along with an ultimate CO2 slug of 100% hydrocarbon pore volume （HCPV） will allow an incremental oil recovery of 18%. The additional recovery increases to 34% if a polymer is injected as a conformance control agent during the course of the WAG process at a ratio of 1：1. According to the results, a pattern reconfiguration change from the nine spot to staggered line drive would represent an incremental oil recovery of 26%.
基金financially supported by the Shandong Province High School Science & Technology Fund Planning Project(No.J13LA52)
文摘Miscibility, isothermal crystallization kinetics, and morphology of poly（L-lactide）/poly（trimethylene carbonate） （PLLA/PTMC） crystalline/amorphous blends were studied by differential scanning calorimetry （DSC） and optical microscopy （OM）. The heterogeneity of OM images and an unchanged glass transition temperature showed that PLLA was immiscible with PTMC. During isothermal crystallization, the crystallization rate of PLLA improved when the PTMC content was low （≤ 20%）. However, when the PTMC content was high （≥ 30%）, the crystallization rate decreased significantly. The reason of these nonlinear changes in crystal kinetics was analyzed according to the nucleation and growth process by virtue of a microscope heating stage. The isothermal crystallization morphologies of the blends were also studied by polarized optical microscopy and the results confirmed the conclusions obtained from crystallization kinetics.
基金This work was financially supported by 863 Programme of China No.863-715-012-0160
文摘Positron annihilation spectroscopy(PAS)was utilized to investigate the relationship between the free-volume hole properties and miscibility of dynamically vulcanized EPDM/PP blend.The results showed that the noncrystalline region of PP and EPDM in the blend was partially miscible and the miscibility of the blend became worse when the weight percent of EPDM was<50%.This was also demonstrated by DMTA and mechanical properties of the blends with various compositions.
