Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solu...Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solution polymerization and applied in the field with a new secondary temporary plugging technique. The optimization and performance evaluation of thermo-sensitive temporary plugging agent were carried out through laboratory experiments. The optimized formula is as follows:(6%-8%) acrylamide +(0.08%-0.12%) ammonium persulfate +(1.5%-2.0%) sepiolite +(0.5%-0.8%) polyethylene glycol diacrylate. The thermo-sensitive temporary plugging agent is suitable for formation temperatures of 70-90 ?C, it has high temporary plugging strength(5-40 k Pa), controllable degradation time(1-15 d), the apparent viscosity after degradation of less than 100 m Pa?S and the permeability recovery value of simulated cores of more than 95%. Based on the research results, secondary temporary plugging technique was used in a horizontal well in the Jidong Oilfield. After treatment, the well saw a drop of water cut to 27%, and now it has a water cut of 67%, its daily increased oil production was 4.8 t, and the cumulative oil increment was 750 t, demonstrating that the technique worked well in controlling water production and increasing oil production.展开更多
For the waterflooding of late development on an offshore oilfield has become worse, and some wells group has entered into high water cut-off period, water plugging work becomes particularly important. Due to the limit...For the waterflooding of late development on an offshore oilfield has become worse, and some wells group has entered into high water cut-off period, water plugging work becomes particularly important. Due to the limited construction of offshore oilfield, space water supply difficulties, and stability of plugging agent, self-generating enhanced foam has been designed as the aimed block plugging system. The formula is determined as: 23.25% of NH4Cl + 30% of NaNO2 + 0.1% of catalyst + 0.6% of COSL-3 foaming agent + 0.25% of HS-type HPAM foam stabilizer. Measurement point of pipe with permeability of 0.5 μm2 and 2 μm2 has been used in the plugging and EOR experiments. The experiments show that this system has the selective plugging effect for the heterogeneous formation, especially for middle and posterior part of high permeability formation, and the recovery rate of low permeability pipe is enhanced up to 32.15%.展开更多
In this paper, to solve the problems of low water absorption and weak pressure bearing capacity of current plugging materials, acrylic acid (AA), acrylamide (AM), and sodium allyl sulfonate (SAS) are used as monomers,...In this paper, to solve the problems of low water absorption and weak pressure bearing capacity of current plugging materials, acrylic acid (AA), acrylamide (AM), and sodium allyl sulfonate (SAS) are used as monomers, and soluble starch is used as grafting. Material, the use of free radical aqueous solution method to synthesize the plugging agent SWL-1 with good water absorption and strong salt resistance. The monomer ratio is set as n (AA):n (AM):n (SAS) = 5:2:1, the experimental synthesis temperature is 70°C, and the orthogonal experiment is used to determine the experimental synthesis conditions as AA neutralization degree 80%, The amount of initiator is 0.60%, the amount of crosslinking agent is 0.50%, the ratio of monomer to starch is 7:1, and the amount of calcium carbonate is 13%. The comprehensive evaluation of the performance of the plugging agent SWL-1 shows that the water absorption performance at 60°C is the best 268.78 g/g, and the water absorption performance in 8% NaCl, 0.9% CaCl<sub>2</sub> and composite brine is 21.5 g/g, 12.5 g/g and 24.9 g/g, indicating good resistance to sodium and calcium, the water retention rate is still higher than 30% after 15 days at 160°C. The sand bed plugging test found that the maximum pressure of SWL-1 was 7 MPa, and the crack plugging test found that when the crack width was 1 mm, 2 mm, and 3 mm, the maximum compressive strength of SWL-1 was 10 MPa. The acid solubility test showed that the maximum pressure was 10 MPa. The highest rate is 86.38%.展开更多
Emulsifier-free poly(methyl methacrylate-styrene) [P(MMA-St)] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcoholwater medium by a solvothermal method. Then, through radica...Emulsifier-free poly(methyl methacrylate-styrene) [P(MMA-St)] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcoholwater medium by a solvothermal method. Then, through radical graft copolymerization of thermo-sensitive mono- mer N-isopropylacrylamide (NIPAm) and hydrophilic monomer acrylic acid (AA) onto the surface of P(MMA- St) nanospheres at 80 ℃, a series of thermo-sensitive polymer nanospheres, named SD-SEAL with different lower critical solution temperatures (LCST), were prepared by adjusting the mole ratio of NIPAm to AA. The products were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, particle size distribution, and specific surface area analysis. The temperature-sensitive behavior was studied by light transmittance tests, while the sealing performance was investigated by pressure transmission tests with Lungmachi Formation shales. The experimental results showed that the synthesized nanoparticles are sensitive to temperature and had apparent LCST values which increased with an increase in hydrophilic monomer AA. When the temperature was higher than its LCST value, SD- SEAL played a dual role of physical plugging and chemical inhibition, slowed down pressure transmission, and reduced shale permeability remarkably. The plugged layer of shale was changed to being hydrophobic, which greatly improved the shale stability展开更多
The finite element method has been applied to simulate the dynamics of a water plugging string in a complex horizontal well of a low-permeability oilfield.The force associated with the pipe string and the packer has b...The finite element method has been applied to simulate the dynamics of a water plugging string in a complex horizontal well of a low-permeability oilfield.The force associated with the pipe string and the packer has been determined under the sucking action of the oil well pump.Such analysis has been conducted for a real drilling well,taking into account the process of lifting,lowering,unblocking and water plugging.Comparison between field measured data and simulation data indicates that the model is reliable and accurate.The packer creep effect under different pressure differences has also been investigated in the framework of the same model.展开更多
Fluid flow characteristics in a four-strand tundish with gas blowing were studied by water modeling experiments.It is found that gas blowing can greatly improve the flow characteristics in the tundish with a turbulenc...Fluid flow characteristics in a four-strand tundish with gas blowing were studied by water modeling experiments.It is found that gas blowing can greatly improve the flow characteristics in the tundish with a turbulence inhibitor.It dramatically increases the peak concentration time,and greatly decreases the dead volume,and reduces the minimum residence time.The gas blowing location,gas flow rate,and porous plug area greatly influence the flow characteristics in the tundish; the gas blowing location near the baffle,smaller gas flow rate,and smaller porous plug area are better for improving the fluid flow characteristics.Using gas blowing can reduce the difference of flows at the middle outlets and side outlets for the multi-strand tundish.Bubbles produced by gas blowing can absorb small inclusions and provide the condition for inclusion collision and aggregation.Therefore,introducing gas blowing into a tundish and combining the turbulence inhibitor can improve inclusion floating and removal,and the cleanness of molten steel can be advanced.展开更多
The geological hazards, such as water inrush and mud outburst, are easily induced by the high water pressure caverns ahead of a karst tunnel face. Therefore, it is a pivotal issue to determine the reserved thickness o...The geological hazards, such as water inrush and mud outburst, are easily induced by the high water pressure caverns ahead of a karst tunnel face. Therefore, it is a pivotal issue to determine the reserved thickness of rock plug during the construction of tunnels. The limit analysis principle is employed to analyze the safe thickness from the point of energy dissipation, and the nonlinear and non-associated characteristics of geotechnical materials are both considered. On the basis of a plane failure pattern of rock plug, the expressions of detaching curve and rock plug thickness are derived. The effect of each parameter on the safe thickness of rock plug is discussed in detail, which interprets the corresponding failure scope of rock plug. The obtained results indicate that the thickness of rock plug is highly influenced by the nonlinear dilatancy coefficient and the nonlinear coefficient. The proposed method is validated by a comparison of the calculated results with those of the engineering project of the "526 karst cavern" of Yunwushan tunnel. This proposed method can provide reference basis for the design and excavation of karst tunnels in the future.展开更多
A semi-implicit and Eulerian - Lagrangian finite difference method for three-dimensionalshallow flow has been extended to a more complete system of equations incorporating second-moment turbulence closure model and tr...A semi-implicit and Eulerian - Lagrangian finite difference method for three-dimensionalshallow flow has been extended to a more complete system of equations incorporating second-moment turbulence closure model and transport equations of salinity and temperature. The simulation for flooding and drying of mudflats has been improved. The model is applied to Xiamen waters. Based on extensive survey data, water level elevation, temperature and salinity field along the eastern open boundary and at the Jiulong River inlets and runoffs are analyzed, specified and calibrated. The computed results show good agreement with the measured data, reproduce flooding, emergence of large and complex mudflat region.展开更多
Ammonium and nitrate concentrations were analyzed in near-bottom water and pore water collected from ten stations of the intertidal flat of the Changjiang Estuary during April, July, November and February. The magnitu...Ammonium and nitrate concentrations were analyzed in near-bottom water and pore water collected from ten stations of the intertidal flat of the Changjiang Estuary during April, July, November and February. The magnitudes of the benthic exchange fluxes were determined on the basis of concentration gradients of ammonium and nitrate at the near-bottom water and interstitial water interface in combination with calculations of a modified Fick' s first law. Ammonium fluxes varied from - 5.05 to 1.43 μg/( cm^2·d) and were greatly regulated by the production of ammonium in surface sediments, while nitrate fluxes ranged from - 0. 38 to 1.36 μg/ ( cm^2·d) and were dominated by nitrate concentrations in the tidal water. It was found that ammonium was mainly released from sediments into water columns at most of stations whereas nitrate was mostly diffused from overlying waters to intertidal sediments. In total, 823.75 t/a ammonium-N was passed from intertidal sediments to water while about 521.90 t/a nitrate-N was removed from overlying waters to intertidal sediments. This suggests that intertidal sediments had the significant influence on modulating inorganic nitrogen in the tidal water.展开更多
Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yiel...Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency(WUE) of high-yield maize under conditions of mulching and drip irrigation.A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days(labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days(D3, D6, D9, D12, and D15).In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize.The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha^-1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m-3, respectively.Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments.These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soilwater evaporation and evapotranspiration, and produce the highest yield and WUE.In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.展开更多
Layer regrouping is to divide all the layers into several sets of production series according to the physical properties and recovery percent of layers at high water-cut stage, which is an important technique to impro...Layer regrouping is to divide all the layers into several sets of production series according to the physical properties and recovery percent of layers at high water-cut stage, which is an important technique to improve oil recovery for high water-cut multilayered reservoirs. Dif- ferent regroup scenarios may lead to different production performances. Based on unstable oil-water flow theory, a multilayer commingled reservoir simulator is established by modifying the production split method. Taking into account the differences of layer properties, including per- meability, oil viscosity, and remaining oil saturation, the pseudo flow resistance contrast is proposed to serve as a characteristic index of layer regrouping for high water-cut multilayered reservoirs. The production indices of multi- layered reservoirs with different pseudo flow resistances are predicted with the established model in which the data are taken from the Shengtuo Oilfield. Simulation results show that the pseudo flow resistance contrast should be less than 4 when the layer regrouping is implemented. The K-means clustering method, which is based on the objec- tive function, is used to automatically carry out the layer regrouping process according to pseudo flow resistances. The research result is applied to the IV-VI sand groups of the second member of the Shahejie Formation in the Shengtuo Oilfield, a favorable development performance is obtained, and the oil recovery is enhanced by 6.08 %.展开更多
Under the water resources perspective,coupling coordination of economy-ecology-society system in Xinjiang was taken as the research object. By building the coupling evaluation index system of the water resources-econo...Under the water resources perspective,coupling coordination of economy-ecology-society system in Xinjiang was taken as the research object. By building the coupling evaluation index system of the water resources-economy-ecology-society system,quantitative evaluation and analysis of the coupling coordination of the water resources-economy-ecology-society system from 2001 to 2014 were conducted. The results showed that benefit indexes of economic system and social system grew rapidly,while benefit indexes of water resources system and ecosystem fluctuated smoothly from 2001 to 2014; coupling state of the whole system was at rival stage,and coupling coordination was reluctant coordination type,and the coupling index was slightly higher than the coupling coordination index. Moreover,it showed that the more the coupling systems,the lower indices of coupling and the coupling coordination.展开更多
[Objective] This study aimed to further explore the dynamics of related physiological indexes of rice seedlings under different NH4+ /NO3- ratio and different water condition. [Method] Under the hydroponic condition ...[Objective] This study aimed to further explore the dynamics of related physiological indexes of rice seedlings under different NH4+ /NO3- ratio and different water condition. [Method] Under the hydroponic condition in laboratory, 3 NH4+/NO3- ratios (0/100, 50/50 and 100/0) and 2 water conditions (+PEG,-PEG) were designed for Fengliangyou 7203. [Result] The root-canopy ratio of rice seedlings increased under any of the NH4+/NO3- ratios and water conditions. Under water stress, the root-canopy ratio of rice seedlings changed most greatly at the NH4+/NO3- ratio of 0/ 100; the overall water potential of rice seedlings reached the lowest at the NH4+/ NO3- ratio of 100/0; and the changes of water potential and xylem flow pH were relatively stable at the NH4+/NO3- ratio of 50/50. Under the condition of no water stress, the growth of rice seedlings was best at the NH4+/NO3- ratio of 50/50, followed by the NH4+/NO3- ratios of 0/100 and 100/0. [Conclusion] This study will pro- vide a basis for understanding the relationship between water potential and xylem flow.展开更多
The molecular dynamics simulation method was adopted to study the transient characteristics of Li^+,CO3^2-,and SO4^2- in Na^+,K^+,Li^+,Cl^-,and SO4^2-/H2O system.The composition of Na^+,K^+,Li^+,Cl^-,SO4^2- and CO3^2-...The molecular dynamics simulation method was adopted to study the transient characteristics of Li^+,CO3^2-,and SO4^2- in Na^+,K^+,Li^+,Cl^-,and SO4^2-/H2O system.The composition of Na^+,K^+,Li^+,Cl^-,SO4^2- and CO3^2- was selected to optimize the initial structural model and conduct dynamic simulation.The mean azimuth shift and diffusion coefficient of Li^+,CO3^2-,and SO4^2- in the system,the radial distribution function and potential energy between Li^+ and -OW,SO4^2- and -OW as well as CO3^2- and -OW,and the dielectric constant of hydrogen bond were expounded and analyzed.At the same time,the Li enrichment behavior in the evaporation process of salt lake brine was analyzed based on the simulated data.The results show that the simulation results are in good agreement with the experimental values,which verifies that,compared with other ions,the crystallization of Li^+ and SO4^2- occurs earlier after reaching saturation.展开更多
[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC...[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC was established, and the influencing factors such as nitrogen pressure and water bath temperature were discussed. [ Result] Detection limit of the method was from 3.2 to 14.1 ng/L, the relative standard deviation was between 4.0% and 9.6%, and the average recovery ranged from 80.8% to 106.0%. By optimizing nitrogen pressure and water bath temperature in the sample pretreatment process, when nitrogen pressure was +0.087 kPa, and water bath temperature was ±36 ℃, recovery effect of this method was better. [ Conclusion] The determination method had accurate qualitative and quantitative results, and met detection requirement of 16 kinds of OCPs in water.展开更多
基金Supported by the National Key Special Science and Technology Project(2016ZX05015-002)PetroChina Key Special Science and Technology Project(2016E-0104)
文摘Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solution polymerization and applied in the field with a new secondary temporary plugging technique. The optimization and performance evaluation of thermo-sensitive temporary plugging agent were carried out through laboratory experiments. The optimized formula is as follows:(6%-8%) acrylamide +(0.08%-0.12%) ammonium persulfate +(1.5%-2.0%) sepiolite +(0.5%-0.8%) polyethylene glycol diacrylate. The thermo-sensitive temporary plugging agent is suitable for formation temperatures of 70-90 ?C, it has high temporary plugging strength(5-40 k Pa), controllable degradation time(1-15 d), the apparent viscosity after degradation of less than 100 m Pa?S and the permeability recovery value of simulated cores of more than 95%. Based on the research results, secondary temporary plugging technique was used in a horizontal well in the Jidong Oilfield. After treatment, the well saw a drop of water cut to 27%, and now it has a water cut of 67%, its daily increased oil production was 4.8 t, and the cumulative oil increment was 750 t, demonstrating that the technique worked well in controlling water production and increasing oil production.
文摘For the waterflooding of late development on an offshore oilfield has become worse, and some wells group has entered into high water cut-off period, water plugging work becomes particularly important. Due to the limited construction of offshore oilfield, space water supply difficulties, and stability of plugging agent, self-generating enhanced foam has been designed as the aimed block plugging system. The formula is determined as: 23.25% of NH4Cl + 30% of NaNO2 + 0.1% of catalyst + 0.6% of COSL-3 foaming agent + 0.25% of HS-type HPAM foam stabilizer. Measurement point of pipe with permeability of 0.5 μm2 and 2 μm2 has been used in the plugging and EOR experiments. The experiments show that this system has the selective plugging effect for the heterogeneous formation, especially for middle and posterior part of high permeability formation, and the recovery rate of low permeability pipe is enhanced up to 32.15%.
文摘In this paper, to solve the problems of low water absorption and weak pressure bearing capacity of current plugging materials, acrylic acid (AA), acrylamide (AM), and sodium allyl sulfonate (SAS) are used as monomers, and soluble starch is used as grafting. Material, the use of free radical aqueous solution method to synthesize the plugging agent SWL-1 with good water absorption and strong salt resistance. The monomer ratio is set as n (AA):n (AM):n (SAS) = 5:2:1, the experimental synthesis temperature is 70°C, and the orthogonal experiment is used to determine the experimental synthesis conditions as AA neutralization degree 80%, The amount of initiator is 0.60%, the amount of crosslinking agent is 0.50%, the ratio of monomer to starch is 7:1, and the amount of calcium carbonate is 13%. The comprehensive evaluation of the performance of the plugging agent SWL-1 shows that the water absorption performance at 60°C is the best 268.78 g/g, and the water absorption performance in 8% NaCl, 0.9% CaCl<sub>2</sub> and composite brine is 21.5 g/g, 12.5 g/g and 24.9 g/g, indicating good resistance to sodium and calcium, the water retention rate is still higher than 30% after 15 days at 160°C. The sand bed plugging test found that the maximum pressure of SWL-1 was 7 MPa, and the crack plugging test found that when the crack width was 1 mm, 2 mm, and 3 mm, the maximum compressive strength of SWL-1 was 10 MPa. The acid solubility test showed that the maximum pressure was 10 MPa. The highest rate is 86.38%.
基金financial support from the National Science Foundation of China (Nos. 51374233, 51474235)the Postdoctoral Innovative Project Foundation of Shandong Province (No. 201602027)+2 种基金the Qingdao Postdoctoral Applied Research Project (No. 2015242)the Fundamental Research Funds for the Central Universities (No. 15CX06021A)the Graduate Student Innovation Project from China University of Petroleum (East China) (No. YCX2015011)
文摘Emulsifier-free poly(methyl methacrylate-styrene) [P(MMA-St)] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcoholwater medium by a solvothermal method. Then, through radical graft copolymerization of thermo-sensitive mono- mer N-isopropylacrylamide (NIPAm) and hydrophilic monomer acrylic acid (AA) onto the surface of P(MMA- St) nanospheres at 80 ℃, a series of thermo-sensitive polymer nanospheres, named SD-SEAL with different lower critical solution temperatures (LCST), were prepared by adjusting the mole ratio of NIPAm to AA. The products were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, particle size distribution, and specific surface area analysis. The temperature-sensitive behavior was studied by light transmittance tests, while the sealing performance was investigated by pressure transmission tests with Lungmachi Formation shales. The experimental results showed that the synthesized nanoparticles are sensitive to temperature and had apparent LCST values which increased with an increase in hydrophilic monomer AA. When the temperature was higher than its LCST value, SD- SEAL played a dual role of physical plugging and chemical inhibition, slowed down pressure transmission, and reduced shale permeability remarkably. The plugged layer of shale was changed to being hydrophobic, which greatly improved the shale stability
文摘The finite element method has been applied to simulate the dynamics of a water plugging string in a complex horizontal well of a low-permeability oilfield.The force associated with the pipe string and the packer has been determined under the sucking action of the oil well pump.Such analysis has been conducted for a real drilling well,taking into account the process of lifting,lowering,unblocking and water plugging.Comparison between field measured data and simulation data indicates that the model is reliable and accurate.The packer creep effect under different pressure differences has also been investigated in the framework of the same model.
文摘Fluid flow characteristics in a four-strand tundish with gas blowing were studied by water modeling experiments.It is found that gas blowing can greatly improve the flow characteristics in the tundish with a turbulence inhibitor.It dramatically increases the peak concentration time,and greatly decreases the dead volume,and reduces the minimum residence time.The gas blowing location,gas flow rate,and porous plug area greatly influence the flow characteristics in the tundish; the gas blowing location near the baffle,smaller gas flow rate,and smaller porous plug area are better for improving the fluid flow characteristics.Using gas blowing can reduce the difference of flows at the middle outlets and side outlets for the multi-strand tundish.Bubbles produced by gas blowing can absorb small inclusions and provide the condition for inclusion collision and aggregation.Therefore,introducing gas blowing into a tundish and combining the turbulence inhibitor can improve inclusion floating and removal,and the cleanness of molten steel can be advanced.
基金Project(2013CB036004) supported by the National Basic Research Program of ChinaProjects(51378510,51308072) supported by National Natural Science Foundation of ChinaProject(CX2014B069) supported by the Hunan Provincial Innovation Foundation for Postgraduate,China
文摘The geological hazards, such as water inrush and mud outburst, are easily induced by the high water pressure caverns ahead of a karst tunnel face. Therefore, it is a pivotal issue to determine the reserved thickness of rock plug during the construction of tunnels. The limit analysis principle is employed to analyze the safe thickness from the point of energy dissipation, and the nonlinear and non-associated characteristics of geotechnical materials are both considered. On the basis of a plane failure pattern of rock plug, the expressions of detaching curve and rock plug thickness are derived. The effect of each parameter on the safe thickness of rock plug is discussed in detail, which interprets the corresponding failure scope of rock plug. The obtained results indicate that the thickness of rock plug is highly influenced by the nonlinear dilatancy coefficient and the nonlinear coefficient. The proposed method is validated by a comparison of the calculated results with those of the engineering project of the "526 karst cavern" of Yunwushan tunnel. This proposed method can provide reference basis for the design and excavation of karst tunnels in the future.
文摘A semi-implicit and Eulerian - Lagrangian finite difference method for three-dimensionalshallow flow has been extended to a more complete system of equations incorporating second-moment turbulence closure model and transport equations of salinity and temperature. The simulation for flooding and drying of mudflats has been improved. The model is applied to Xiamen waters. Based on extensive survey data, water level elevation, temperature and salinity field along the eastern open boundary and at the Jiulong River inlets and runoffs are analyzed, specified and calibrated. The computed results show good agreement with the measured data, reproduce flooding, emergence of large and complex mudflat region.
基金This research is part of the project of the biogeochemical cycling of multi-materials in the Changjiang estuarine and coastal complex ecosystem supported by the National Natural Science Key Foundation of China under contract Nos 40131020 and 49801018 the Tidal Flat Project by Science and Technology Committee of Shanghai under contract No. 04DZ12049+1 种基金 China Postdoctoral Science Foundation under contract No. 2005037135 Shanghai Postdoctoral Science Foundation under contract No.04R214122.
文摘Ammonium and nitrate concentrations were analyzed in near-bottom water and pore water collected from ten stations of the intertidal flat of the Changjiang Estuary during April, July, November and February. The magnitudes of the benthic exchange fluxes were determined on the basis of concentration gradients of ammonium and nitrate at the near-bottom water and interstitial water interface in combination with calculations of a modified Fick' s first law. Ammonium fluxes varied from - 5.05 to 1.43 μg/( cm^2·d) and were greatly regulated by the production of ammonium in surface sediments, while nitrate fluxes ranged from - 0. 38 to 1.36 μg/ ( cm^2·d) and were dominated by nitrate concentrations in the tidal water. It was found that ammonium was mainly released from sediments into water columns at most of stations whereas nitrate was mostly diffused from overlying waters to intertidal sediments. In total, 823.75 t/a ammonium-N was passed from intertidal sediments to water while about 521.90 t/a nitrate-N was removed from overlying waters to intertidal sediments. This suggests that intertidal sediments had the significant influence on modulating inorganic nitrogen in the tidal water.
基金research support from the National Key Research and Development Program of China (2016YFD0300110, 2016YFD0300101)the National Basic Research Program of China (2015CB150401)+2 种基金the National Natural Science Foundation of China (31360302)the Science and Technology Program of the Sixth Division of Xinjiang Construction Corps in China (1703)the Agricultural Science and Technology Innovation Program for financial support.
文摘Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency(WUE) of high-yield maize under conditions of mulching and drip irrigation.A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days(labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days(D3, D6, D9, D12, and D15).In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize.The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha^-1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m-3, respectively.Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments.These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soilwater evaporation and evapotranspiration, and produce the highest yield and WUE.In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.
基金supported by the Program for Changjiang Scholars and Innovative Research Team in University(IRT1294)the China National Science and Technology Major Projects(Grant No:2016ZX05011)
文摘Layer regrouping is to divide all the layers into several sets of production series according to the physical properties and recovery percent of layers at high water-cut stage, which is an important technique to improve oil recovery for high water-cut multilayered reservoirs. Dif- ferent regroup scenarios may lead to different production performances. Based on unstable oil-water flow theory, a multilayer commingled reservoir simulator is established by modifying the production split method. Taking into account the differences of layer properties, including per- meability, oil viscosity, and remaining oil saturation, the pseudo flow resistance contrast is proposed to serve as a characteristic index of layer regrouping for high water-cut multilayered reservoirs. The production indices of multi- layered reservoirs with different pseudo flow resistances are predicted with the established model in which the data are taken from the Shengtuo Oilfield. Simulation results show that the pseudo flow resistance contrast should be less than 4 when the layer regrouping is implemented. The K-means clustering method, which is based on the objec- tive function, is used to automatically carry out the layer regrouping process according to pseudo flow resistances. The research result is applied to the IV-VI sand groups of the second member of the Shahejie Formation in the Shengtuo Oilfield, a favorable development performance is obtained, and the oil recovery is enhanced by 6.08 %.
基金Supported by"Effect Evaluation of Xinjiang Implementing the First Round of Subsidy Reward Mechanism Policy of Grassland Eco-protection" from Special Item of Xinjiang Animal Husbandry DepartmentPublic Welfare Scientific Research Project of Xinjiang Uygur Autonomous Region(XK201516)
文摘Under the water resources perspective,coupling coordination of economy-ecology-society system in Xinjiang was taken as the research object. By building the coupling evaluation index system of the water resources-economy-ecology-society system,quantitative evaluation and analysis of the coupling coordination of the water resources-economy-ecology-society system from 2001 to 2014 were conducted. The results showed that benefit indexes of economic system and social system grew rapidly,while benefit indexes of water resources system and ecosystem fluctuated smoothly from 2001 to 2014; coupling state of the whole system was at rival stage,and coupling coordination was reluctant coordination type,and the coupling index was slightly higher than the coupling coordination index. Moreover,it showed that the more the coupling systems,the lower indices of coupling and the coupling coordination.
基金Supported by Natural Science Foundation of Guangdong Province(2014 A030307013)~~
文摘[Objective] This study aimed to further explore the dynamics of related physiological indexes of rice seedlings under different NH4+ /NO3- ratio and different water condition. [Method] Under the hydroponic condition in laboratory, 3 NH4+/NO3- ratios (0/100, 50/50 and 100/0) and 2 water conditions (+PEG,-PEG) were designed for Fengliangyou 7203. [Result] The root-canopy ratio of rice seedlings increased under any of the NH4+/NO3- ratios and water conditions. Under water stress, the root-canopy ratio of rice seedlings changed most greatly at the NH4+/NO3- ratio of 0/ 100; the overall water potential of rice seedlings reached the lowest at the NH4+/ NO3- ratio of 100/0; and the changes of water potential and xylem flow pH were relatively stable at the NH4+/NO3- ratio of 50/50. Under the condition of no water stress, the growth of rice seedlings was best at the NH4+/NO3- ratio of 50/50, followed by the NH4+/NO3- ratios of 0/100 and 100/0. [Conclusion] This study will pro- vide a basis for understanding the relationship between water potential and xylem flow.
基金Funded by the Innovation Academy for Green Manufacture,CAS“IAGM2020C01”the Key R&D and the Transformation Projects in Qinghai Province(2019-GX-167)CAS“Light of West China”。
文摘The molecular dynamics simulation method was adopted to study the transient characteristics of Li^+,CO3^2-,and SO4^2- in Na^+,K^+,Li^+,Cl^-,and SO4^2-/H2O system.The composition of Na^+,K^+,Li^+,Cl^-,SO4^2- and CO3^2- was selected to optimize the initial structural model and conduct dynamic simulation.The mean azimuth shift and diffusion coefficient of Li^+,CO3^2-,and SO4^2- in the system,the radial distribution function and potential energy between Li^+ and -OW,SO4^2- and -OW as well as CO3^2- and -OW,and the dielectric constant of hydrogen bond were expounded and analyzed.At the same time,the Li enrichment behavior in the evaporation process of salt lake brine was analyzed based on the simulated data.The results show that the simulation results are in good agreement with the experimental values,which verifies that,compared with other ions,the crystallization of Li^+ and SO4^2- occurs earlier after reaching saturation.
文摘[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC was established, and the influencing factors such as nitrogen pressure and water bath temperature were discussed. [ Result] Detection limit of the method was from 3.2 to 14.1 ng/L, the relative standard deviation was between 4.0% and 9.6%, and the average recovery ranged from 80.8% to 106.0%. By optimizing nitrogen pressure and water bath temperature in the sample pretreatment process, when nitrogen pressure was +0.087 kPa, and water bath temperature was ±36 ℃, recovery effect of this method was better. [ Conclusion] The determination method had accurate qualitative and quantitative results, and met detection requirement of 16 kinds of OCPs in water.