Residence times of Manukau Harbour,New Zealand     

W. N. Vant  B. L. Williams 《新西兰海洋与淡水研究杂志》2013,47(3-4):393-404

Residence times of the three main channel systems of Manukau Harbour were calculated by methods based on the salinity measured in 10 tidal excursion segments: the freshwater replacement technique and a volume exchange model. The amount of freshwater present in the segments at high water was low (< 11% throughout the year), so salinities were high, with minimum values (winter) in each segment being in the range 30.1–34.0 (compared with a median value of 34.5 in the nearby coastal waters). The proportion of each segments’ volume which was exchanged with an adjacent segment during a tidal cycle varied markedly across the harbour, from ≤ 5 % in several shallow inner harbour segments to 65% in a deep segment adjacent to the entrance channel. For annual average conditions the freshwater replacement times of the channels were 11–18 days. Slightly longer residence times—12–26 days—were obtained from the volume exchange model. Calculated replacement times for two non‐conservative tracers— inorganic phosphorus and nitrogen—were approximately half those for freshwater, as 5–12% of these species disappeared from the water column each day.  相似文献   

多工艺联合洗井和抽水试验在CGSD-01井中的应用          下载免费PDF全文

陈浩文  宋志彬  和国磊  李胜涛  许本冲  马汉臣  杜垚森  殷国乐 《探矿工程》2019,46(6):8-13

天津东丽湖CGSD-01井为地热勘探井,设计井深4000 m,完钻井深4051.68 m。为最大程度清理钻井过程中对含水层的堵塞,本井采用了焦磷酸钠洗井、压缩空气洗井和酸化洗井3种工艺方法联合洗井,并先后进行2次抽水试验。联合抽水试验表明多工艺联合洗井效果理想。本文主要阐述了CGSD-01井洗井及抽水试验实施工艺,以期为今后同类研究及施工提供有益的借鉴。  相似文献   

绿色地质勘查综合技术应用分析          下载免费PDF全文

贾占宏  高元宏  梁俭  刘海声  陈佰辉 《探矿工程》2017,44(4):1-4

绿色地质勘查是青海省乃至我国地质找矿发展的必然趋势。开展绿色地质勘查需要了解地质勘查工程影响生态环境的范围及形式,在此基础上综合多种先进的勘探技术手段,以最大程度降低扰动地表生态环境为基础满足预查、普查等阶段的地质找矿目的。其方法包括结合环保型冲洗液、浅层取样钻探、便携钻探设备浅孔钻探、重型钻探设备深部钻探与多向分支定向钻探取样方法等,并综合资料探索三维地质建模的方法开展绿色地质勘查。  相似文献   

多种钻探工艺技术在白涧铁矿区的应用实践          下载免费PDF全文

李光宏  李红梅 《探矿工程》2017,44(9):49-52

白涧铁矿区地层复杂多变,褶皱、断裂极为发育,使得钻探施工难度大。根据其地层条件,采用了多种钻探工艺技术,包括弹子式单管钻进、PDC绳索取心钻进、跟管钻进、金刚石绳索取心钻进。根据地层条件不同,采取了不同的冲洗液配制方案,在施工过程中灵活配合使用,取得良好的效果,顺利完成了预期任务。取得了明显的经济效益并积累了经验。  相似文献   

绿色勘查技术在青海格尔木铜金山矿区钻探施工的应用分析          下载免费PDF全文

刘海声  穆元红  刘鹏  高元宏  窦斌  汪洪民  庞怀玮  张世元 《探矿工程》2017,44(3):27-30

青海省格尔木市铜金山矿区是青海省2016年实施的11个绿色勘查示范项目之一。以该矿区为例,在钻探施工中,根据工程概况,选择具体的绿色勘查技术方案,形成可复制、可推广的经验做法。通过分析可以得到,绿色勘查技术在海拔高、自然条件恶劣、植被稀疏的地区可以应用,并且在设备选用、道路修筑、施工区及生活区修建等辅助工序方面总结可供推广的经验。同时,由于矿区的局限性,在环保型冲洗液的使用等影响钻探施工的核心技术方面还需进一步研究。  相似文献   

无固相冲洗液在变质岩系复杂地层绳索取心钻进中的应用          下载免费PDF全文

刘志峰 《探矿工程》2017,44(4):14-18

辽宁省北镇市杜屯地区超大型石墨矿处于变质岩系中,在勘查过程中分析了该区变质岩系复杂地层的成因及特点,采用了绳索取心与无固相冲洗液钻进工艺,并分析了冲洗液对石墨岩矿层稳定性的影响,对冲洗液体系进行了优化,分析了冲洗液的护壁作用机理。同时对钻进过程中的技术应对措施进行了优化,解决了绳索取心钻进过程中钻杆结泥皮及技术套管的使用等问题,顺利地完成了矿床的勘探工作,取得了良好的技术经济成果。  相似文献   

南黄海大陆架科钻CSDP-02井第四系、新近系地层海水冲洗液研究与应用   总被引：2，自引：2，他引：0       下载免费PDF全文

宋世杰  李晓东  陈师逊 《探矿工程》2017,44(4):10-13

针对南黄海大陆架科学钻探第四系、新近系地层,通过室内实验,以多功能剂（MBM）和抗盐共聚物（GTQ）为主要处理剂,选出适合第四系、新近系地层的冲洗液配方,并在CSDP-02井海上施工现场应用,取得了良好的效果,保证了钻探施工在第四系、新近系地层中的顺利进行。  相似文献   

Continuous flushing of contaminants from ballast water tanks     

Eames I  Landeryou M  Greig A  Snellings J 《Marine pollution bulletin》2008,56(2):250-260

The transport of non-indigenous species (NIS) with ship ballast water is a major environmental problem. The International Maritime Organisation (IMO) have recommended that ballast tanks are flushed through with sea water to remove NIS contaminants. The flushing efficiency is studied using mathematical models and a scaled experimental model of a ballast tank. The density contrast between the ballast water and water used for flushing is important when the Froude number Fr(w)=U(w)/sqr rt|g(')|H < 1 (defined in terms of average horizontal flow U(w), reduced buoyancy g', and H the vertical dimension in the tank). When denser water is used to flush a ballast tank, from below, it efficiently displaces lighter ballast water; but flushing through with light water creates a buoyant gravity current which effectively short circuits part of the tank. When Fr(w)>1, the density contrast between the ballast water and water used for flushing is not important and flushing is controlled by a bulk Péclet number, Pe(w). For Pe(w)<1 perfect mixing occurs, while for Pe(w)>1 displacement flushing occurs. Laboratory experiments of flushing were performed using a model two-dimensional ballast tank employing dye attenuation to measure the whole concentration field and these experiments confirm the essential features of the mathematical models. The results of this study are discussed in the context of current IMO flushing protocols.  相似文献   

Response characteristics of DOC flushing in an alpine catchment     

Elizabeth W. Boyer  George M. Hornberger  Kenneth E. Bencala  Diane M. McKnight 《水文研究》1997,11(12):1635-1647

The spatial distribution of source areas and associated residence times of water in the catchment are significant factors controlling the annual cycles of dissolved organic carbon (DOC) concentration in Deer Creek (Summit County, Colorado). During spring snowmelt (April–August 1992), stream DOC concentrations increased with the rising limb of the hydrograph, peaked before maximum discharge, then declined rapidly as melting continued. We investigated catchment sources of DOC to streamflow, measuring DOC in tension lysimeters, groundwater wells, snow and streamflow. Lysimeter data indicate that near-surface soil horizons are a primary contributor of DOC to streamflow during spring snowmelt. Concentrations of DOC in the lysimeters decrease rapidly during the melt period, supporting the hypothesis that hydrological flushing of catchment soils is the primary mechanism affecting the temporal variation of DOC in Deer Creek. Time constants of DOC flushing, characterizing the exponential decay of DOC concentration in the upper soil horizon, ranged from 10 to 30 days for the 10 lysimeter sites. Differences in the rate of flushing are influenced by topographical position, with near-stream riparian soils flushed more quickly than soils located further upslope. Variation in the amount of distribution of accumulated snow, and asynchronous melting of the snowpack across the landscape, staggered the onset of the spring flush throughout the catchment, prolonging the period of increased concentrations of DOC in the stream. Streamflow integrates the catchment-scale flushing responses, yielding a time constant associated with the recession of DOC in the stream channel (84 days) that is significantly longer than the time constants observed for particular locations in the upper soil. © 1997 John Wiley & Sons, Ltd.  相似文献   

Physical and coupled fully three-dimensional numerical modeling of pressurized bottom outlet flushing processes in reservoirs     

Ousmane Sawadogo  Gerrit R. Basson  Simon Schneiderbauer 《国际泥沙研究》2019,34(5):461-474

Sediment deposition in reservoirs is an important research topic in engineering practice. Reservoir sedimentation has the potential to affect ood levels, drainage for agricultural land, pump station and hydropower operation as well as navigation. This paper describes the development of a coupled fully three-dimensional (3D) numerical model for the prediction of the local sediment ushing scour upstream of the bottom outlet. The presented numerical model solves the Navier-Stokes equations in conjunction with the k- turbulence model which includes both sediment transport and hydrodynamic parameters. The proposed coupled fully 3D numerical model is used to simulate experimental tests based on non-cohesive sediment. The geometric features of the scour hole (temporal and spatial hole devel- opment) upstream of the bottom outlet were reasonably well predicted compared to the experimental data. Furthermore, the velocity eld upstream of the bottom outlet was in good agreement with mea- surements. The proposed numerical model for bottom outlet ushing was, therefore, validated because of its ability to accurately predict the scour hole development during the ushing process. The proposed numerical model can be considered reliable provided that the model is correctly calibrated and set up to re ect the conditions of a particular case study.  相似文献