A novel type curve is presented for oil recovery factor prediction suitable for gas flooding by innovatively introducing the equivalent water-gas cut to replace the water cut,comprehensively considering the impact of ...A novel type curve is presented for oil recovery factor prediction suitable for gas flooding by innovatively introducing the equivalent water-gas cut to replace the water cut,comprehensively considering the impact of three-phase flow(oil,gas,water),and deriving the theoretical equations of gas flooding type curve based on Tong’s type curve.The equivalent water-gas cut is the ratio of the cumulative underground volume of gas and water production to the total underground volume of produced fluids.Field production data and the numerical simulation results are used to demonstrate the feasibility of the new type curve and verify the accuracy of the prediction results with field cases.The new type curve is suitable for oil recovery factor prediction of both water flooding and gas flooding.When a reservoir has no gas injected or produced,the gas phase can be ignored and only the oil and water phases need to be considered,in this case,this gas flooding type curve returns to the Tong’s type curve,which can evaluate the oil recovery factor of water flooding.For reservoirs with equivalent water-gas cuts of 60%-80%,the regression method of the new type curve works well in predicting the oil recovery factor.For reservoirs with equivalent water-gas cuts higher than 80%,both the regression and assignment methods of the new type curve can accurately predict the oil recovery factor of gas flooding.展开更多
This research was conducted to study the influence of NaHCO3and fertilizer treatments on flooded soils tothe chemistry of soil and rice plant growth.The experiment was done in a greenhouse using a split-split plot des...This research was conducted to study the influence of NaHCO3and fertilizer treatments on flooded soils tothe chemistry of soil and rice plant growth.The experiment was done in a greenhouse using a split-split plot design ofthree factors: two types of soil,three doses of fertilizers and three levels of NaHCO3with three replications.The firstfactor was two kind of soils Fluvaquent and Calciquert,the factor was without nutrient(blank),macro nutrients,andcompletely nutrients(second macro and micro nutrients),and the third factor was 0 mg/kg,200 mg/kg and 400 mg/kgof NaHCO3or equivalent with 0 mg,1 200 mg and 2 400 mg NaHCO3per pot.Each experimental unit used a pot of 10L capacity and filled with soil mud equivalent with 6 kg of dried soil.After each of treatment combination mixed into themud soil,two plants of IR-32 variety were grown,and flooded at5 cm high accordingly with growth period.Parametersobserved were the growth of tillers,electrical conductivity(E.C.) and pH.The experiment results showed that the treatment of NaHCO3increased the soluble salt content(E.C.) and soilacidity(pH) during flooding on Calciquerts and Fluvaquents.The content of soluble salt decreased to 2.0 mmhos/cm,while pHon Calciquert decreased towards the neutral pH.Anyhowthe pHon Fluvaquents increased approach to neutral.The treatments of NaHCO3inhibited the tiller growth,either macro fertilizer and completely fertilizer increased thetillers,but did not improve the negative effect of alkalinity due to of NaHCOtreatment.展开更多
To compare the oil displacement mechanisms and performances of continuous phase flooding agent(traditional polymer solution) and dispersed phase flooding agent(particle-type polymer SMG dispersion), the particle phase...To compare the oil displacement mechanisms and performances of continuous phase flooding agent(traditional polymer solution) and dispersed phase flooding agent(particle-type polymer SMG dispersion), the particle phase separation of SMG dispersion migrating in pores was simulated by using the microfluidic technology. Theoretically guided by the tree fork concentration distribution of red cells in biological fluid mechanics, the concentration distribution mathematical model of SMG in different pores is established. Furthermore, the micro and macro physical simulation experiments of continuous and dispersed phase flooding agents were carried out. The results show that the continuous flooding agent enters all the swept zones and increases the flow resistance in both larger and small pores. On the contrary, the particle phase separation phenomenon occurs during the injection process of dispersed flooding agent. The SMG particles gather in the larger pore to form bridge blinding, and the carrier fluid displace oil in the small pore. Working in cooperation, the SMG particle and carrier fluid drive the residual oil in the low permeability layers step by step and achieve the goal of enhanced oil recovery. The laboratory experimental results indicate that, the oil increment and water reduction effect of dispersed flooding agent is much better than that of continuous flooding agent, which is consistent with the field test results.展开更多
To improve flood control efficiency and increase urban resilience to flooding,the impacts of forest type change on flood control in the upper reach of the Tingjiang River(URTR) were evaluated by a modified model based...To improve flood control efficiency and increase urban resilience to flooding,the impacts of forest type change on flood control in the upper reach of the Tingjiang River(URTR) were evaluated by a modified model based on the Soil Conservation Service curve number(SCS-CN) method. Parameters of the model were selected and determined according to the comprehensive analysis of model evaluation indexes. The first simulation of forest reconstruction scenario,namely a coniferous forest covering 59.35km^2 is replaced by a broad-leaved forest showed no significant impact on the flood reduction in the URTR. The second simulation was added with 61.75km^2 bamboo forest replaced by broad-leaved forest,the reduction of flood peak discharge and flood volume could be improved significantly. Specifically,flood peak discharge of 10-year return period event was reduced to 7-year event,and the reduction rate of small flood was 21%-28%. Moreover,the flood volume was reduced by 9%-14% and 18%-35% for moderate floods and small floods,respectively. The resultssuggest that the bamboo forest reconstruction is an effective control solution for small to moderate flood in the URTR,the effect of forest conversion on flood volume is increasingly reduced as the rainfall amount increases to more extreme magnitude. Using a hydrological model with scenarios analysis is an effective simulation approach in investigating the relationship between forest type change and flood control. This method would provide reliable support for flood control and disaster mitigation in mountainous cities.展开更多
The design of the flow field is highly responsible for the performance of the Proton Exchange Membrane Fuel Cell (PEMFC). In this study, pin type flow channel is numerically analyzed by arranging carbon made porous ma...The design of the flow field is highly responsible for the performance of the Proton Exchange Membrane Fuel Cell (PEMFC). In this study, pin type flow channel is numerically analyzed by arranging carbon made porous material in uniform and zigzag manner on the rib surface of the flow field. The study focuses on enhancing the performance of PEMFC by reducing liquid flooding in the interface between the rib and Gas Diffusion Layer (GDL). A single PEMFC having an active area of 25 cm2, with three flow channel designs (conventional serpentine, pin type flow channel with 2 mm cubical porous inserts in zigzag and uniform pattern) are modeled for the numerical analysis. The effect of porosity of the carbon inserts on the cell performance is studied by varying its value from 0.6 to 0.9. The results show that the performance of the flow channel with zigzag and uniformly positioned porous inserts is more than the conventional serpentine flow channel by 20.36% and 16.87% respectively. The reason for this increase is the removal of the accumulated water from the rib surface due to the capillary action of the porous carbon inserts. This helps in eliminating the stagnant water regions under the rib and thereby helps in reducing liquid flooding.展开更多
Winter-flooded paddy field is an agricultural method which putting a water among the winter, it is paid attention as an environmental friendly agriculture. Especially, it is said, winter-flooding is control paddy weed...Winter-flooded paddy field is an agricultural method which putting a water among the winter, it is paid attention as an environmental friendly agriculture. Especially, it is said, winter-flooding is control paddy weeds and there is the farming potential that the annual rice yield is high. However, there is no detailed research about the effects of weed communities by winter-flooding, as the purpose of this study, we investigated the effects of the inhibition of weed communities (life cycle, harmful weed) by winter-flooding at a shore of Inba Lake, Chiba Prefecture, Japan, and compared them to paddy weeds in a dry paddy field. Methods examined the plant height (cm) and the cover degree class of all appearance species in each quadrant frame (1 m2). Quadrant in the two type paddies were 10 frames (D1-D10) at the control, and were 10 frames (W1-W10) at the treatment (Figure 1). In a winter-flooded paddy field, species number and plant volume of winter-annual plants decreased in the third winter after winter-flooding, In particular, the plant volume of Alopecurus aequalis, Cardamine flexuosa decreased significantly. We considered that the cause of this decrease was due to the depth of flooding (more than 10 cm). Eleocharis kuroguwai and Echinochloa oryzoides, which are perennial plants, Sagittaria trifolia, which is an annual plant, increased in a winter-flooded paddy field in the third summer after winter-flooding. We considered that these species grew thicker at places where the seeds germinated, and grew easily, because the conservation situation of the seeds fitted well under the winter-flooding conditions. They started to grow immediately after the drainage of water. The period of drainage coincided with increasing light intensity and temperature. In addition, the annual rice yield of the third year after winter-flooding was higher than that of the habitual practice rice field.展开更多
基金Supported by the National Natural Science Foundation of China(51974268)the Sichuan Province Science and Technology Program(2019YJ0423)。
文摘A novel type curve is presented for oil recovery factor prediction suitable for gas flooding by innovatively introducing the equivalent water-gas cut to replace the water cut,comprehensively considering the impact of three-phase flow(oil,gas,water),and deriving the theoretical equations of gas flooding type curve based on Tong’s type curve.The equivalent water-gas cut is the ratio of the cumulative underground volume of gas and water production to the total underground volume of produced fluids.Field production data and the numerical simulation results are used to demonstrate the feasibility of the new type curve and verify the accuracy of the prediction results with field cases.The new type curve is suitable for oil recovery factor prediction of both water flooding and gas flooding.When a reservoir has no gas injected or produced,the gas phase can be ignored and only the oil and water phases need to be considered,in this case,this gas flooding type curve returns to the Tong’s type curve,which can evaluate the oil recovery factor of water flooding.For reservoirs with equivalent water-gas cuts of 60%-80%,the regression method of the new type curve works well in predicting the oil recovery factor.For reservoirs with equivalent water-gas cuts higher than 80%,both the regression and assignment methods of the new type curve can accurately predict the oil recovery factor of gas flooding.
基金the Directorat of High Education,Dept.of National Education of the Republic of Indonesia
文摘This research was conducted to study the influence of NaHCO3and fertilizer treatments on flooded soils tothe chemistry of soil and rice plant growth.The experiment was done in a greenhouse using a split-split plot design ofthree factors: two types of soil,three doses of fertilizers and three levels of NaHCO3with three replications.The firstfactor was two kind of soils Fluvaquent and Calciquert,the factor was without nutrient(blank),macro nutrients,andcompletely nutrients(second macro and micro nutrients),and the third factor was 0 mg/kg,200 mg/kg and 400 mg/kgof NaHCO3or equivalent with 0 mg,1 200 mg and 2 400 mg NaHCO3per pot.Each experimental unit used a pot of 10L capacity and filled with soil mud equivalent with 6 kg of dried soil.After each of treatment combination mixed into themud soil,two plants of IR-32 variety were grown,and flooded at5 cm high accordingly with growth period.Parametersobserved were the growth of tillers,electrical conductivity(E.C.) and pH.The experiment results showed that the treatment of NaHCO3increased the soluble salt content(E.C.) and soilacidity(pH) during flooding on Calciquerts and Fluvaquents.The content of soluble salt decreased to 2.0 mmhos/cm,while pHon Calciquert decreased towards the neutral pH.Anyhowthe pHon Fluvaquents increased approach to neutral.The treatments of NaHCO3inhibited the tiller growth,either macro fertilizer and completely fertilizer increased thetillers,but did not improve the negative effect of alkalinity due to of NaHCOtreatment.
基金Supported by the China Postdoctoral Science Foundation(Grant No.2018M641610)China National Science and Technology Major Project(2016ZX05025-003)
文摘To compare the oil displacement mechanisms and performances of continuous phase flooding agent(traditional polymer solution) and dispersed phase flooding agent(particle-type polymer SMG dispersion), the particle phase separation of SMG dispersion migrating in pores was simulated by using the microfluidic technology. Theoretically guided by the tree fork concentration distribution of red cells in biological fluid mechanics, the concentration distribution mathematical model of SMG in different pores is established. Furthermore, the micro and macro physical simulation experiments of continuous and dispersed phase flooding agents were carried out. The results show that the continuous flooding agent enters all the swept zones and increases the flow resistance in both larger and small pores. On the contrary, the particle phase separation phenomenon occurs during the injection process of dispersed flooding agent. The SMG particles gather in the larger pore to form bridge blinding, and the carrier fluid displace oil in the small pore. Working in cooperation, the SMG particle and carrier fluid drive the residual oil in the low permeability layers step by step and achieve the goal of enhanced oil recovery. The laboratory experimental results indicate that, the oil increment and water reduction effect of dispersed flooding agent is much better than that of continuous flooding agent, which is consistent with the field test results.
基金funded by the National Natural Science Foundation of China (Grants No.51278239)
文摘To improve flood control efficiency and increase urban resilience to flooding,the impacts of forest type change on flood control in the upper reach of the Tingjiang River(URTR) were evaluated by a modified model based on the Soil Conservation Service curve number(SCS-CN) method. Parameters of the model were selected and determined according to the comprehensive analysis of model evaluation indexes. The first simulation of forest reconstruction scenario,namely a coniferous forest covering 59.35km^2 is replaced by a broad-leaved forest showed no significant impact on the flood reduction in the URTR. The second simulation was added with 61.75km^2 bamboo forest replaced by broad-leaved forest,the reduction of flood peak discharge and flood volume could be improved significantly. Specifically,flood peak discharge of 10-year return period event was reduced to 7-year event,and the reduction rate of small flood was 21%-28%. Moreover,the flood volume was reduced by 9%-14% and 18%-35% for moderate floods and small floods,respectively. The resultssuggest that the bamboo forest reconstruction is an effective control solution for small to moderate flood in the URTR,the effect of forest conversion on flood volume is increasingly reduced as the rainfall amount increases to more extreme magnitude. Using a hydrological model with scenarios analysis is an effective simulation approach in investigating the relationship between forest type change and flood control. This method would provide reliable support for flood control and disaster mitigation in mountainous cities.
文摘The design of the flow field is highly responsible for the performance of the Proton Exchange Membrane Fuel Cell (PEMFC). In this study, pin type flow channel is numerically analyzed by arranging carbon made porous material in uniform and zigzag manner on the rib surface of the flow field. The study focuses on enhancing the performance of PEMFC by reducing liquid flooding in the interface between the rib and Gas Diffusion Layer (GDL). A single PEMFC having an active area of 25 cm2, with three flow channel designs (conventional serpentine, pin type flow channel with 2 mm cubical porous inserts in zigzag and uniform pattern) are modeled for the numerical analysis. The effect of porosity of the carbon inserts on the cell performance is studied by varying its value from 0.6 to 0.9. The results show that the performance of the flow channel with zigzag and uniformly positioned porous inserts is more than the conventional serpentine flow channel by 20.36% and 16.87% respectively. The reason for this increase is the removal of the accumulated water from the rib surface due to the capillary action of the porous carbon inserts. This helps in eliminating the stagnant water regions under the rib and thereby helps in reducing liquid flooding.
文摘Winter-flooded paddy field is an agricultural method which putting a water among the winter, it is paid attention as an environmental friendly agriculture. Especially, it is said, winter-flooding is control paddy weeds and there is the farming potential that the annual rice yield is high. However, there is no detailed research about the effects of weed communities by winter-flooding, as the purpose of this study, we investigated the effects of the inhibition of weed communities (life cycle, harmful weed) by winter-flooding at a shore of Inba Lake, Chiba Prefecture, Japan, and compared them to paddy weeds in a dry paddy field. Methods examined the plant height (cm) and the cover degree class of all appearance species in each quadrant frame (1 m2). Quadrant in the two type paddies were 10 frames (D1-D10) at the control, and were 10 frames (W1-W10) at the treatment (Figure 1). In a winter-flooded paddy field, species number and plant volume of winter-annual plants decreased in the third winter after winter-flooding, In particular, the plant volume of Alopecurus aequalis, Cardamine flexuosa decreased significantly. We considered that the cause of this decrease was due to the depth of flooding (more than 10 cm). Eleocharis kuroguwai and Echinochloa oryzoides, which are perennial plants, Sagittaria trifolia, which is an annual plant, increased in a winter-flooded paddy field in the third summer after winter-flooding. We considered that these species grew thicker at places where the seeds germinated, and grew easily, because the conservation situation of the seeds fitted well under the winter-flooding conditions. They started to grow immediately after the drainage of water. The period of drainage coincided with increasing light intensity and temperature. In addition, the annual rice yield of the third year after winter-flooding was higher than that of the habitual practice rice field.
