Design and operation problems related to water curtain system forunderground water-sealed oil storage caverns

The underground water-sealed storage technique is critically important and generally accepted for the national energy strategy in China. Although several small underground water-sealed oil storage caverns have been built in China since the 1970s, there is still a lack of experience for large-volume underground storage in complicated geological conditions. The current design concept of water curtain system and the technical instruction for system operation have limitations in maintaining the stability of surrounding rock mass during the construction of the main storage caverns, as well as the long-term stability. Although several large-scale underground oil storage projects are under construction at present in China, the design concepts and construction methods, especially for the water curtain system, are mainly based on the ideal porosity medium flow theory and the experiences gained from the similar projects overseas. The storage projects currently constructed in China have the specific features such as huge scale, large depth, multiple-level arrangement, high seepage pressure, complicated geological conditions, and high in situ stresses, which are the challenging issues for the stability of the storage caverns. Based on years’ experiences obtained from the first large-scale （millions of cubic meters） underground water-sealed oil storage project in China, some design and operation problems related to water curtain system during project construction are discussed. The drawbacks and merits of the water curtain system are also presented. As an example, the conventional concept of “filling joints with water” is widely used in many cases, as a basic concept for the design of the water curtain system, but it is immature. In this paper, the advantages and disadvantages of the conventional concept are pointed out, with respect to the long-term stability as well as the safety of construction of storage caverns. Finally, new concepts and principles for design and construction of the underground water-sealed oil storage caverns are proposed.

Structural Design and Performance Analysis of a Deep-Water Ball Joint Seal

To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in this paper.The spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene(PTFE).Rational structural design makes the seal independent from the ball and other components,making it easy to replace if leakage occurs at its surface.PTFE can elastically deform over a certain deformation range,which guarantees that two sealing surfaces fit tightly together.O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical surfaces.Using a finite element technique and nonlinear theory,the performance of the spherical seal under the influence of various factors is determined.The results show that the spherical seal designed in this paper exhibits excellent sealing performance under lowtemperature and high-pressure conditions.The spherical seal,a combination of an O-ring and PTFE,has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.

2219铝合金酒石酸-硫酸阳极氧化工艺研究

以航天领域常用的2219铝合金为研究对象,通过单因素实验和正交试验研究了酒石酸浓度、硫酸浓度、氧化温度、氧化时间和氧化电压对酒石酸-硫酸阳极氧化膜的微观形貌、厚度和耐蚀性的影响,并研究了热水封闭时间对氧化膜耐蚀性能的影响。结果表明:当硫酸浓度为50 g/L,酒石酸浓度为80 g/L,氧化电压为16 V,氧化温度为35℃,氧化时间为28 min时,阳极氧化膜的耐蚀性最佳。阳极氧化膜的耐蚀性随热水封闭时间的增加而先增加后减少,当热水封闭时间为40 min时,其耐腐蚀性能最佳,经336 h中性盐雾实验后无腐蚀斑点产生。

水浴密封消解-原子荧光法测定土壤中的汞和砷

建立水浴密封消解-原子荧光法测定土壤中的汞和砷。采用一次性聚丙烯离心管、恒温水浴振荡器为消解设备,取样质量为0.3~0.5 g,以5 mL王水溶液(1∶1)为消解液,消解时间为1 h。汞、砷的质量浓度分别在0~2、0~20μg/L范围内与荧光强度线性关系良好,相关系数分别为0.999 7、0.999 8,汞和砷的检出限分别为0.001、0.01 mg/kg,定量限分别为0.004、0.04 mg/kg。采用该方法对土壤成分分析标准物质GSS-8、GSS-23、GSS-29进行测定,汞和砷测定结果的相对标准偏差分别为3.5%~6.6%、1.8%~3.8%(n=6),相对误差分别为-3.3%~4.9%、-2.1%~2.5%。汞和砷的回收率分别为93.7%~104%、98.6%~102%。该方法采用一次性聚丙烯离心管,无需消清洗解管,消解过程简单,消解液用量少,适用于大批量土壤样品测定。

关于GB 50208-2011中腻子型遇水膨胀止水条物理性能要求的修订建议

分析了GB 50208—2011《地下防水工程质量验收规范》对腻子型遇水膨胀止水条物理性能的要求,指出了其与现行相关标准存在的不协调问题,如7 d膨胀率≤最终膨胀率60%的规定导致合规产品可能无法通过验收检测。在此基础上,针对该验收规范对腻子型遇水膨胀止水条物理性能的要求提出修订建议:取消有关试验条件的规定;取消21 d膨胀率作为最终膨胀率的规定;取消7 d膨胀率≤最终膨胀率60%的要求;明确硬度测试方法。

基于时间-温度拟合曲线的岩心密闭试验参数优化方法

密闭试验是含气储层含水观察常用方法,但是在实际操作过程中试验温度与密闭时间没有统一标准,观察结果对比性较差,不利于岩性含水性的判断。通过试验测定在不同温度下岩心水分挥发量与时间的关系,用曲线拟合方法,优选出岩心密闭试验最佳参数组合,结果表明,在60℃条件下,密闭时间为120 min后观察袋壁附着水珠产状效果最佳。参数定量后,密闭试验的可比性显著增强,实现了从单井解释到井间对比,在油田勘探开发中具有一定的应用前景。

Three-dimensional hydrodynamic model of Xiamen waters

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.

The diffusive fluxes of inorganic nitrogen across the intertidal sediment-water interface of the Changjiang Estuary in China

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.

Using irrigation intervals to optimize water-use efficiency and maize yield in Xinjiang,northwest China

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.

Layer regrouping for water-flooded commingled reservoirs at a high water-cut stage

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 %.

The Coupling Coordination Evolution Research of Economy - Ecology - Society System in Xinjiang：Based on the Interaction Perspective of Water Resources

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.

Protection Performance of Plasma Sprayed Al_(2)O_(3)-13 wt%TiO_(2) Coating Sealed with an Organic-inorganic Hybrid Agent

An organic-inorganic hybrid sealing agent was fabricated and used in the plasma sprayed Al_(2)O_(3)-13 wt%TiO_(2)coating,and conventional silicone agent was also used for comparison.Protection performance of the coatings was comprehensively evaluated based on both anti-corrosion and anti-biofouling properties.The results reveal that the sealing treatment is remarkably useful to decrease the porosity of the coating,and the porosity of the coating sealed with the hybrid agent is only 0.035%.Immersion corrosion test and Tafel polarization test reveal that the sealed coating with the hybrid agent exhibits a better corrosion resistance by compared with the coating sealed with silicone agent.The corrosion current density i_(corr) of the hybrid agent sealed coating is only 0.7×10^(-6)A·cm^(-2).Moreover,anti-biofouling tests both in the outdoor analogue hydraulic environment and in the natural marine environment prove that the mentioned novel coating presents a better combination of corrosion resistance and anti-biofouling property by compared with the other coatings,and it could be used as a protection of metal components in the marine environment.

AMEX-10-SEAL在输水钢管局部修复中的应用

以上海市区原水引水管渠闸凌支线输水钢管局部修复为例,探讨了国内首次将AMEX-10-SEAL修复技术应用在输水钢管中的情况。分析了AMEX-10-SEAL管道接头修复技术的原理、工艺特点、施工流程和使用效果,工程实践表明,该技术在输水钢管局部修复中具有工艺成熟、施工便捷、工期短、对周边环境影响小等特点。

强烈非均质裂隙介质优先流及其工程意义--以HN地下水封洞库为例

在地下洞库工程建设中,低渗岩体内发育的节理密集带、断层等空隙中通常形成优先流,从而对洞库涌水量与储品水封安全性造成严重影响,因此裂隙介质优先流的识别、工程风险评估以及防渗控制研究具有重要意义。以HN地下水封石油洞库为例,使用FEFLOW地下水模拟工具的非结构化剖分技术对优先流潜在通道进行了精细的几何刻画,建立了工程场区尺度的地下水水流模型,并对施工期中优先流防渗处置不同工况下洞库涌水量与储品水封安全性进行了模拟分析。结果表明:优先流是影响洞库围岩中地下水的流场形态以及洞库涌水量的重要因素,断层、节理密集带等不连续面是主洞室涌水主要的充水途径,优先流形成的涌水量占据主洞室总涌水量的60%以上。在地下工程施工期间做好优先流通道的防渗处理是必不可少的工作。

Effects of Different NH_4^+/NO_3^- Ratio and Water Condition on Physiological Characteristics of Rice Seedlings

[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.

Lithium Behavior in Salt-water System Explored by Molecular Dynamics Simulation

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.

Determination of 16 Species 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.

Preliminary Study on Water Demand Law of 1-0 Rooted Cuttings of Populus szechuanica

In order to provide theoretical basis and technical support for the afforestation and artificial water supply of P.szechuanica in arid areas,the characteristics of water consumption of P.szechuanica were explored,and the law of water demand of P.szechuanica was grasped.In this paper,potted seedlings of 1-0 rooted cuttings of P.szechuanica were taken as research objects,and change situation of water consumption under different water control gradients was measured regularly by using weighing method,further analyzing dynamic change of water consumption of P.szechuanica and revealing water demand law of 1-0 rooted cuttings of P.szechuanica.The results showed that total change of water consumption of 1-0 rooted cuttings of P.szechuanica had"slow-fast-slow-fast"double-peak trend in the growth period of the current year,and corresponded with univariate linear relation(R^(2)=0.7137),with significant difference.In whole growth period,water consumption in August was the highest,which was 2.7 times of that in June and July and 1.5 times of that after September.In different water control treatments,the dynamic changes of daily and monthly water consumption were significantly different.In seven water control treatments,monthly water consumption was between(6315.95±1690.70)and(10105.28±3065.30)g/month,and mean was(8211.07±2308.23)g/month.With intensification of water control treatment,water consumption increased,but there was no seedling death due to water shortage.P.szechuanica has great plasticity in water demand,and can survive in both arid and humid environments.Meanwhile,it is revealed that P.szechuanica is the most widely distributed tree species in the region.

2015 IWA Alternative Water Resources Conference Nanjing,China(May 26-28,2015)

The IWA Alternative Water Resources（AWR）Conference is organized by the International Water Association,Hohai University,the IWA China Chapter of the AWR Cluster,and the Seawater Desalination and AWR Utilization Research Center of Hohai University.

Water-Deficit Response Is Not Affected by Glutathione Deficiency in Arabidopsis thaliana pad2-1 Plants

Changes in glutathione and ascorbate content, hydrogen peroxide and abscisic acid were studied in developing leaves in wild-type (Col-0) and glutathione-deficient mutant pad2-1 lines of Arabidopsis thaliana over a time period of 9 days of drought followed by re-watering. Glutathione deficient mutant (pad2-1) presents mechanisms of acclimation to water stress through the reduction of plant biomass and increase in endogenous concentrations of ascorbate and glutathione. These acclimation responses to stress appeared along with the first symptoms of stress and we suggest here that they are regulated by ABA and H2O2. Normally, wild type plants under conditions of stress require an initial response phase in which a decrease in antioxidants is observed before reaching acclimation through the increase in levels of antioxidants. pad2-1 is more sensitive to stress and reacts to it;however, it did not suffer more oxidative stress than Col-0 plants, even though pad2-1 had higher levels of endogenous H2O2 relative to wild-type. In both water stressed Col-0 and pad2-1 plants increases in ABA were observed, however, more sharply in wild-type stressed plants. Low levels of glutathione together with high levels of H2O2 may regulate endogenous ABA concentrations and could be related to the slow growth rates which were observed during the experiment. The results highlighted the double function of glutathione as an antioxidant and signal molecule and also, the different response patterns of wild-type and pad2-1 when faced with drought stress. The results bring new insights to the responses of pad2-1 under conditions of water stress.