Deep condensate gas reservoirs exhibit highly complex and variable phase behaviors,making it crucial to understand the relationship between fluid phase states and flow patterns.This study conducts a comprehensive anal...Deep condensate gas reservoirs exhibit highly complex and variable phase behaviors,making it crucial to understand the relationship between fluid phase states and flow patterns.This study conducts a comprehensive analysis of the actual production process of the deep condensate gas well A1 in a certain oilfield in China.Combining phase behavior analysis and CMG software simulations,the study systematically investigates phase transitions,viscosity,and density changes in the gas and liquid phases under different pressure conditions,with a reservoir temperature of 165°C.The research covers three crucial depletion stages of the reservoir:single-phase flow,two-phase transition,and two-phase flow.The findings indicate that retrograde condensation occurs when the pressure falls below the dew point pressure,reachingmaximum condensate liquid production at around 25MPa.As pressure decreases,gas phase density and viscosity gradually decrease,while liquid phase density and viscosity show an increasing trend.In the initial single-phase flow stage,maintaining a consistent gas-oil ratio is observed when both bottom-hole and reservoir pressures are higher than the dew point pressure.However,a sudden drop in bottom-hole pressure below the dew point triggers the production of condensate oil,significantly reducing subsequent gas and oil production.In the transitional two-phase flow stage,as the bottom-hole pressure further decreases,the reservoir exhibits a complex flow regime with coexisting areas of gas and liquid.In the subsequent two-phase flow stage,when both bottom-hole and reservoir pressures are below the dew point pressure,a significant increase in the gas-oil ratio is observed.The reservoir manifests a two-phase flow regime,devoid of single-phase gas flow areas.For lowpressure conditions in deep condensate gas reservoirs,considerations include gas injection,gas lift,and cyclic gas injection and production in surrounding wells.Additionally,techniques such as hot nitrogen or CO_(2) injection can be employed to mitigate retrograde condensation damage.The implications of this study are crucial for developing targeted development strategies and enhancing the overall development of deep condensate gas reservoirs.展开更多
In this work,a high-performance fiber strain sensor is fabricated by constructing a double percolated structure,consisting of carbon nanotube(CNT)/thermoplastic polyurethane(TPU)continuous phase and styrene butadiene ...In this work,a high-performance fiber strain sensor is fabricated by constructing a double percolated structure,consisting of carbon nanotube(CNT)/thermoplastic polyurethane(TPU)continuous phase and styrene butadiene styrene(SBS)phase,incompatible with TPU(CNT/TPU@SBS).Compared with other similar fiber strain sensor systems without double percolated structure,the CNT/TPU@SBS sensor achieves a lower percolation threshold(0.38 wt.%)and higher electrical conductivity.The conductivity of 1%-CNT/TPU@SBS(4.12×10^(-3) S·m^(-1))is two orders of magnitude higher than that of 1%-CNT/TPU(3.17×10^(-5) S·m^(-1))at the same CNT loading of 1 wt.%.Due to double percolated structure,the 1%-CNT/TPU@SBS sensor exhibits a wide strain detection range(0.2%-100%)and an ultra-high sensitivity(maximum gauge factor(GF)is 32411 at 100%strain).Besides,the 1%-CNT/TPU@SBS sensor shows a high linearity(R^(2)=0.97)at 0%-20%strain,relatively fast response time(214 ms),and stability(500 loading/unloading cycles).The designed sensor can efficiently monitor physiological signals and movements and identify load distribution after being woven into a sensor array,showing broad application prospects in wearable electronics.展开更多
We report progress towards a modern scientific description of thermodynamic properties of fluids following the discovery (in 2012) of a coexisting critical density hiatus and a supercritical mesophase defined by perco...We report progress towards a modern scientific description of thermodynamic properties of fluids following the discovery (in 2012) of a coexisting critical density hiatus and a supercritical mesophase defined by percolation transitions. The state functions density ρ(p,T), and Gibbs energy G(p,T), of fluids, e.g. CO<sub>2</sub>, H<sub>2</sub>O and argon exhibit a symmetry characterised by the rigidity, ω = (dp/dρ)<sub>T</sub>, between gaseous and liquid states along any isotherm from critical (T<sub>c</sub>) to Boyle (T<sub>B</sub>) temperatures, on either side of the supercritical mesophase. Here, using experimental data for fluid argon, we investigate the low-density cluster physics description of an ideal dilute gas that obeys Dalton’s partial pressure law. Cluster expansions in powers of density relate to a supercritical liquid-phase rigidity symmetry (RS) line (ω = ρ<sub>rs</sub>(T) = RT) to gas phase virial coefficients. We show that it is continuous in all derivatives, linear within stable fluid phase, and relates analytically to the Boyle-work line (BW) (w = (p/ρ)<sub>T</sub> = RT), and to percolation lines of gas (PB) and liquid (PA) phases by: ρ<sub>BW</sub>(T) = 2ρ<sub>PA</sub>(T) = 3ρ<sub>PB</sub>(T) = 3ρ<sub>RS</sub>(T)/2 for T T<sub>B</sub>. These simple relationships arise, because the higher virial coefficients (b<sub>n</sub>, n ≥ 4) cancel due to clustering equilibria, or become negligible at all temperatures (0 T T<sub>B</sub>)<sub> </sub>within the gas phase. The Boyle-work line (p/ρ<sub>BW</sub>)<sub>T</sub> is related exactly at lower densities as T → T<sub>B</sub>, and accurately for liquid densities, by ρ<sub>BW</sub>(T) = −(b<sub>2</sub>/b<sub>3</sub>)<sub>T</sub>. The RS line, ω(T) = RT, defines a new liquid-density ground-state physical constant (ρ<sub>RS</sub>(0) = (2/3)ρ<sub>BW</sub>(0) for argon). Given the gas-liquid rigidity symmetry, the entire thermodynamic state functions below T<sub>B</sub> are obtainable from b<sub>2</sub>(T). A BW-line ground-state crystal density ρ<sub>BW</sub>(0) can be defined by the pair potential minimum. The Ar<sub>2</sub> pair potential, ∅ij</sub>(r<sub>ij</sub>) determines b<sub>2</sub>(T) analytically for all T. This report, therefore, advances the salient objective of liquid-state theory: an argon p(ρ,T) Equation-of-state is obtained from ∅<sub>ij</sub>(r<sub>ij</sub>) for all fluid states, without any adjustable parameters.展开更多
We carry out a chemical treatment(acidization or basification)of typical rock specimens in-situ,and characterize the emerging pattern resulting from the infil-tration-precipitation scenario.Galena and limestone sam-pl...We carry out a chemical treatment(acidization or basification)of typical rock specimens in-situ,and characterize the emerging pattern resulting from the infil-tration-precipitation scenario.Galena and limestone sam-ples were treated with sulfuric acid,while pyrite was reacted with sodium hydroxide.Various infiltration tech-niques were employed,after selection of the most feasible method for each rock separately.The patterns of anglesite(PbSO_(4)),anhydrite(CaSO_(4))and goethite(FeOOH)depo-sition presented different alteration modes of the bare rock textures.Among the three deposited minerals,only the anhydrite(CaSO_(4))displayed a band stratification.The formation of a Liesegang pattern in the rock of highest porosity indicates a plausible correlation between the band formation and a minimum porosity requirement.A banded rock of compact texture could then be formed by a cementation mechanism,governing the long time evolution of the rock.展开更多
A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of...A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of the NN interaction.Recently the interplay between a rotational-symmetry-breaking continuous phase transition and percolation has been explored for an equilibrium system of asymmetrically interacting(i.e.,attractive PP interaction,zero NN and PN interactions)Janus disks on the triangular lattice.By Monte Carlo simulation and finite-size scaling analysis,in this work we study an equilibrium system of symmetrically interacting(i.e.,attractive PP and NN interactions with the same strength,zero PN interaction)Janus disks on the same lattice.By definition,the phase diagram in the T-θplane is symmetric for systems with patch sizesθbelow and above 90°.We determine the phase diagram and compare it with that of the asymmetric system.Similar to the latter system,for 60°<θ<90°,a rotational-symmetry-breaking continuous phase transition and an anisotropic percolation transition are found in the symmetric system,though the transition points in the two systems are quite different.Phase crossover curves are found to be different,e.g.,a continuous varying crossover line extends betweenθ=0°and 90°for the symmetric model;and in the range 0°<θ≤30°,along the crossover lines of the two models,the trends of 1/T vs.θare opposite in the two systems.We understand the latter by analytically solving the models with two particles in 0°<θ≤30°.These results are helpful for understanding close-packed systems of Janus disks with more complex interactions.展开更多
We propose a model of edge-coupled interdependent networks with directed dependency links(EINDDLs)and develop the theoretical analysis framework of this model based on the self-consistent probabilities method.The phas...We propose a model of edge-coupled interdependent networks with directed dependency links(EINDDLs)and develop the theoretical analysis framework of this model based on the self-consistent probabilities method.The phase transition behaviors and parameter thresholds of this model under random attacks are analyzed theoretically on both random regular(RR)networks and Erd¨os-Renyi(ER)networks,and computer simulations are performed to verify the results.In this EINDDL model,a fractionβof connectivity links within network B depends on network A and a fraction(1-β)of connectivity links within network A depends on network B.It is found that randomly removing a fraction(1-p)of connectivity links in network A at the initial state,network A exhibits different types of phase transitions(first order,second order and hybrid).Network B is rarely affected by cascading failure whenβis small,and network B will gradually converge from the first-order to the second-order phase transition asβincreases.We present the critical values ofβfor the phase change process of networks A and B,and give the critical values of p andβfor network B at the critical point of collapse.Furthermore,a cascading prevention strategy is proposed.The findings are of great significance for understanding the robustness of EINDDLs.展开更多
目的:评价1层和2层Percoll密度梯度离心法分离精子的效果。方法:20份精液标本分别行50%1层,90%和45%Percoll2层密度梯度离心分离,处理前后应用SCA(sperm class analyzer)精子质量分析仪分析精子密度、活力和圆形细胞密度。结果:1层法分...目的:评价1层和2层Percoll密度梯度离心法分离精子的效果。方法:20份精液标本分别行50%1层,90%和45%Percoll2层密度梯度离心分离,处理前后应用SCA(sperm class analyzer)精子质量分析仪分析精子密度、活力和圆形细胞密度。结果:1层法分离后精子回收率为(65.5±12.8)%,明显高于2层法(P<0.01);1层和2层法分离后a级精子百分率明显高于处理前(P<0.05,P<0.01),而1层法分离后a级精子百分率明显低于2层法(P<0.05);1层法分离精子后c级精子百分率明显高于2层法(P<0.05),与处理前相比没有明显差异(P>0.05);2层法分离后a+b级精子百分率明显高于处理前(P<0.05),1层法分离后a+b级精子百分率与处理前相比没有明显差异(P>0.05);1层和2层法分离后圆形细胞密度明显低于处理前(P<0.05,P<0.01),两种方法之间没有差异(P>0.05)。结论:1层法分离后精子回收率较高,精子的活力改变不大;2层法分离后精子回收率较低,精子的活力明显改善;1层和2层法都可以较好地把精子与圆形细胞分开。两种方法各有优势,在精子体外处理中都有着重要的应用价值。展开更多
基金funding from the Key Research Project of Tarim Oilfield Company of Petrochina(671023060003)for this study.
文摘Deep condensate gas reservoirs exhibit highly complex and variable phase behaviors,making it crucial to understand the relationship between fluid phase states and flow patterns.This study conducts a comprehensive analysis of the actual production process of the deep condensate gas well A1 in a certain oilfield in China.Combining phase behavior analysis and CMG software simulations,the study systematically investigates phase transitions,viscosity,and density changes in the gas and liquid phases under different pressure conditions,with a reservoir temperature of 165°C.The research covers three crucial depletion stages of the reservoir:single-phase flow,two-phase transition,and two-phase flow.The findings indicate that retrograde condensation occurs when the pressure falls below the dew point pressure,reachingmaximum condensate liquid production at around 25MPa.As pressure decreases,gas phase density and viscosity gradually decrease,while liquid phase density and viscosity show an increasing trend.In the initial single-phase flow stage,maintaining a consistent gas-oil ratio is observed when both bottom-hole and reservoir pressures are higher than the dew point pressure.However,a sudden drop in bottom-hole pressure below the dew point triggers the production of condensate oil,significantly reducing subsequent gas and oil production.In the transitional two-phase flow stage,as the bottom-hole pressure further decreases,the reservoir exhibits a complex flow regime with coexisting areas of gas and liquid.In the subsequent two-phase flow stage,when both bottom-hole and reservoir pressures are below the dew point pressure,a significant increase in the gas-oil ratio is observed.The reservoir manifests a two-phase flow regime,devoid of single-phase gas flow areas.For lowpressure conditions in deep condensate gas reservoirs,considerations include gas injection,gas lift,and cyclic gas injection and production in surrounding wells.Additionally,techniques such as hot nitrogen or CO_(2) injection can be employed to mitigate retrograde condensation damage.The implications of this study are crucial for developing targeted development strategies and enhancing the overall development of deep condensate gas reservoirs.
基金This work was supported by the National Natural Science Foundation of China(Grant No.12102374)the National Key Research and Development Program(Grant No.2019YFE0120300)+2 种基金the Sichuan Science and Technology Program(Grant No.2021YFH0031)the International Cooperation Project of Chengdu(Grant No.2019-GH02-00054-HZ)the Innovative Research Team of SWPU(Grant No.2017CXTD01).
文摘In this work,a high-performance fiber strain sensor is fabricated by constructing a double percolated structure,consisting of carbon nanotube(CNT)/thermoplastic polyurethane(TPU)continuous phase and styrene butadiene styrene(SBS)phase,incompatible with TPU(CNT/TPU@SBS).Compared with other similar fiber strain sensor systems without double percolated structure,the CNT/TPU@SBS sensor achieves a lower percolation threshold(0.38 wt.%)and higher electrical conductivity.The conductivity of 1%-CNT/TPU@SBS(4.12×10^(-3) S·m^(-1))is two orders of magnitude higher than that of 1%-CNT/TPU(3.17×10^(-5) S·m^(-1))at the same CNT loading of 1 wt.%.Due to double percolated structure,the 1%-CNT/TPU@SBS sensor exhibits a wide strain detection range(0.2%-100%)and an ultra-high sensitivity(maximum gauge factor(GF)is 32411 at 100%strain).Besides,the 1%-CNT/TPU@SBS sensor shows a high linearity(R^(2)=0.97)at 0%-20%strain,relatively fast response time(214 ms),and stability(500 loading/unloading cycles).The designed sensor can efficiently monitor physiological signals and movements and identify load distribution after being woven into a sensor array,showing broad application prospects in wearable electronics.
文摘We report progress towards a modern scientific description of thermodynamic properties of fluids following the discovery (in 2012) of a coexisting critical density hiatus and a supercritical mesophase defined by percolation transitions. The state functions density ρ(p,T), and Gibbs energy G(p,T), of fluids, e.g. CO<sub>2</sub>, H<sub>2</sub>O and argon exhibit a symmetry characterised by the rigidity, ω = (dp/dρ)<sub>T</sub>, between gaseous and liquid states along any isotherm from critical (T<sub>c</sub>) to Boyle (T<sub>B</sub>) temperatures, on either side of the supercritical mesophase. Here, using experimental data for fluid argon, we investigate the low-density cluster physics description of an ideal dilute gas that obeys Dalton’s partial pressure law. Cluster expansions in powers of density relate to a supercritical liquid-phase rigidity symmetry (RS) line (ω = ρ<sub>rs</sub>(T) = RT) to gas phase virial coefficients. We show that it is continuous in all derivatives, linear within stable fluid phase, and relates analytically to the Boyle-work line (BW) (w = (p/ρ)<sub>T</sub> = RT), and to percolation lines of gas (PB) and liquid (PA) phases by: ρ<sub>BW</sub>(T) = 2ρ<sub>PA</sub>(T) = 3ρ<sub>PB</sub>(T) = 3ρ<sub>RS</sub>(T)/2 for T T<sub>B</sub>. These simple relationships arise, because the higher virial coefficients (b<sub>n</sub>, n ≥ 4) cancel due to clustering equilibria, or become negligible at all temperatures (0 T T<sub>B</sub>)<sub> </sub>within the gas phase. The Boyle-work line (p/ρ<sub>BW</sub>)<sub>T</sub> is related exactly at lower densities as T → T<sub>B</sub>, and accurately for liquid densities, by ρ<sub>BW</sub>(T) = −(b<sub>2</sub>/b<sub>3</sub>)<sub>T</sub>. The RS line, ω(T) = RT, defines a new liquid-density ground-state physical constant (ρ<sub>RS</sub>(0) = (2/3)ρ<sub>BW</sub>(0) for argon). Given the gas-liquid rigidity symmetry, the entire thermodynamic state functions below T<sub>B</sub> are obtainable from b<sub>2</sub>(T). A BW-line ground-state crystal density ρ<sub>BW</sub>(0) can be defined by the pair potential minimum. The Ar<sub>2</sub> pair potential, ∅ij</sub>(r<sub>ij</sub>) determines b<sub>2</sub>(T) analytically for all T. This report, therefore, advances the salient objective of liquid-state theory: an argon p(ρ,T) Equation-of-state is obtained from ∅<sub>ij</sub>(r<sub>ij</sub>) for all fluid states, without any adjustable parameters.
基金supported by a grant from the University Research Board(URB)of the American University of Beirut(AUB).
文摘We carry out a chemical treatment(acidization or basification)of typical rock specimens in-situ,and characterize the emerging pattern resulting from the infil-tration-precipitation scenario.Galena and limestone sam-ples were treated with sulfuric acid,while pyrite was reacted with sodium hydroxide.Various infiltration tech-niques were employed,after selection of the most feasible method for each rock separately.The patterns of anglesite(PbSO_(4)),anhydrite(CaSO_(4))and goethite(FeOOH)depo-sition presented different alteration modes of the bare rock textures.Among the three deposited minerals,only the anhydrite(CaSO_(4))displayed a band stratification.The formation of a Liesegang pattern in the rock of highest porosity indicates a plausible correlation between the band formation and a minimum porosity requirement.A banded rock of compact texture could then be formed by a cementation mechanism,governing the long time evolution of the rock.
基金supported by the National Natural Science Foundation of China(Grant No.11905001)。
文摘A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of the NN interaction.Recently the interplay between a rotational-symmetry-breaking continuous phase transition and percolation has been explored for an equilibrium system of asymmetrically interacting(i.e.,attractive PP interaction,zero NN and PN interactions)Janus disks on the triangular lattice.By Monte Carlo simulation and finite-size scaling analysis,in this work we study an equilibrium system of symmetrically interacting(i.e.,attractive PP and NN interactions with the same strength,zero PN interaction)Janus disks on the same lattice.By definition,the phase diagram in the T-θplane is symmetric for systems with patch sizesθbelow and above 90°.We determine the phase diagram and compare it with that of the asymmetric system.Similar to the latter system,for 60°<θ<90°,a rotational-symmetry-breaking continuous phase transition and an anisotropic percolation transition are found in the symmetric system,though the transition points in the two systems are quite different.Phase crossover curves are found to be different,e.g.,a continuous varying crossover line extends betweenθ=0°and 90°for the symmetric model;and in the range 0°<θ≤30°,along the crossover lines of the two models,the trends of 1/T vs.θare opposite in the two systems.We understand the latter by analytically solving the models with two particles in 0°<θ≤30°.These results are helpful for understanding close-packed systems of Janus disks with more complex interactions.
基金the National Natural Science Foundation of China(Grant Nos.61973118,51741902,11761033,12075088,and 11835003)Project in JiangXi Province Department of Science and Technology(Grant Nos.20212BBE51010 and 20182BCB22009)the Natural Science Foundation of Zhejiang Province(Grant No.Y22F035316)。
文摘We propose a model of edge-coupled interdependent networks with directed dependency links(EINDDLs)and develop the theoretical analysis framework of this model based on the self-consistent probabilities method.The phase transition behaviors and parameter thresholds of this model under random attacks are analyzed theoretically on both random regular(RR)networks and Erd¨os-Renyi(ER)networks,and computer simulations are performed to verify the results.In this EINDDL model,a fractionβof connectivity links within network B depends on network A and a fraction(1-β)of connectivity links within network A depends on network B.It is found that randomly removing a fraction(1-p)of connectivity links in network A at the initial state,network A exhibits different types of phase transitions(first order,second order and hybrid).Network B is rarely affected by cascading failure whenβis small,and network B will gradually converge from the first-order to the second-order phase transition asβincreases.We present the critical values ofβfor the phase change process of networks A and B,and give the critical values of p andβfor network B at the critical point of collapse.Furthermore,a cascading prevention strategy is proposed.The findings are of great significance for understanding the robustness of EINDDLs.
文摘目的:评价1层和2层Percoll密度梯度离心法分离精子的效果。方法:20份精液标本分别行50%1层,90%和45%Percoll2层密度梯度离心分离,处理前后应用SCA(sperm class analyzer)精子质量分析仪分析精子密度、活力和圆形细胞密度。结果:1层法分离后精子回收率为(65.5±12.8)%,明显高于2层法(P<0.01);1层和2层法分离后a级精子百分率明显高于处理前(P<0.05,P<0.01),而1层法分离后a级精子百分率明显低于2层法(P<0.05);1层法分离精子后c级精子百分率明显高于2层法(P<0.05),与处理前相比没有明显差异(P>0.05);2层法分离后a+b级精子百分率明显高于处理前(P<0.05),1层法分离后a+b级精子百分率与处理前相比没有明显差异(P>0.05);1层和2层法分离后圆形细胞密度明显低于处理前(P<0.05,P<0.01),两种方法之间没有差异(P>0.05)。结论:1层法分离后精子回收率较高,精子的活力改变不大;2层法分离后精子回收率较低,精子的活力明显改善;1层和2层法都可以较好地把精子与圆形细胞分开。两种方法各有优势,在精子体外处理中都有着重要的应用价值。
