Transient‐state groundwater flow in various geometries with wells at arbitrary positions: analytical methods     

M. W. Roth  C. M Wilson  M. Z. Iqbal 《水文研究》2003,17(17):3519-3530

We have developed a method for analytically solving the porous medium flow equation in many different geometries for horizontal (two‐dimensional), homogeneous and isotropic aquifers containing impermeable boundaries and any number of pumping or injection wells located at arbitrary positions within the system. Solutions and results are presented for rectangular and circular aquifers but the method presented here is easily extendible to many geometries. Results are also presented for systems where constant head boundary conditions can be emulated internal to the aquifer boundary. Recommendations for extensions of the present work are briefly discussed. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Detection of free vertical convection and double-diffusion in groundwater monitoring wells with geophysical borehole measurements     

Susann Berthold  Frank Börner 《Environmental Geology》2008,54(7):1547-1566

Two algorithms for in-situ detection and identification of vertical free convective and double-diffusive flows in groundwater monitoring wells or boreholes are proposed. With one algorithm the causes (driving forces) and with the other one the effects (convection or double-diffusion) of vertical transport processes can be detected based on geophysical borehole measurements in the water column. Five density-driven flow processes are identified: thermal, solutal, and thermosolutal convection leading to an equalization, as well as saltfingers and diffusive layering leading to an intensification of a vertical density gradient. The occurrence of density-driven transport processes could be proven in many groundwater monitoring wells and boreholes; especially shallow sections of boreholes or groundwater monitoring wells are affected dramatically by such vertical flows. Deep sections are also impaired as the critical threshold for the onset of a density-driven flow is considerably low. In monitoring wells or boreholes, several sections with different types of density-driven vertical flows may exist at the same time. Results from experimental investigations in a medium-scale testing facility with high aspect ratio (height/radius = 19) and from numerical modeling of a water column agree well with paramters of in-situ detected convection cells.  相似文献   

汕尾市100kW波力电站空气透平与气室匹配设计   总被引：3，自引：0，他引：3  

梁贤光 《海洋工程》2005,23(1):53-61

根据用1/15模型,在造波水槽中进行试验获得气室的Δ Pi- Q、ηA- Q、 NA- Q特性,以及用300mm透平模型,在1000mm活塞式往复流透平试验台进行试验获得的对称翼透平、双向固定导叶冲动透平和双向自调节导叶冲动透平的CP-、ηT-特性,进行了气室与三种空气透平的匹配设计。表明在设计波况下,采用1.025m的双向自调节导叶冲动透平时,ηT·ηA达50.43%;采用0.975m的双向自调节导叶冲动透平时,ηT·ηA达46.66%;采用0.975m的双向固定导叶冲动透平时,ηT·ηA达33.66%;采用1.45m对称翼透平时,ηT·ηA仅为29.9%。并对四种不同匹配方案进行了对比分析。  相似文献   

低渗透储层水平井—直井联合布井极限注采井距研究     

侯晓春  陆程  蔡文  郑兴范 《现代地质》2008,22(1)

低渗透储层水平井—直井联合布井技术具有广泛的应用前景,其布井方式至关重要。首先利用劈分流场的方法直观地给出常规储层水平井—直井联合布井的产能评价方法;然后针对低渗透储层的渗流特点,在考虑启动压力梯度条件下建立新的井网渗流物理模型并求解得到产能评价公式;最后经分析计算给出启动压力梯度影响的面积井网极限注采井距关系曲线。研究结果为低渗透储层部署水平井—直井联合井网提供理论依据。  相似文献   

Glacio-lacustrine stratigraphy,aquifer characterization and contaminant transport: a case study in South Lake Tahoe,California, USA     

Craig W. Morgan  Graham M. Kent  Gordon G. Seitz  Michaela Novak 《Hydrogeology Journal》2008,16(5):981-994

A hydrogeologic model that has been used by many researchers and consultants to describe an area of South Lake Tahoe, California, USA impacted by MTBE contamination describes a relatively homogeneous unconfined aquifer comprised of poorly sorted glacial outwash deposits, within which water-supply wells are able to exert significant alteration in natural groundwater flow. A re-examination of the area’s hydrogeology is presented, which supports a layered heterogeneous aquifer system constructed of alternating fine and coarser-grained glacio-lacustrine depositional units. This re-evaluation was accomplished through a review of lithologic logs across an area of approximately 1 km², combined with observations of significant hydraulic head differences and knowledge of the depositional environments controlled by Pleistocene Lake Tahoe high stands. Many of the fine-grained units observed at depths from 6 to 15 m, although relatively thin, are generally continuous and serve as significant barriers to groundwater flow. The vertical migration of contamination across these fine-grained units to deeper groundwaters was facilitated by cross-screened monitoring wells installed as part of site investigation activities. This conclusion highlights the importance of geologic characterization and proper monitoring well construction at contaminated site investigations.

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Electronic supplementary material   The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Michaela NovakEmail:

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一种基于双重距离的空间聚类方法   总被引：10，自引：1，他引：9  

李光强  邓敏  程涛  朱建军 《测绘学报》2008,37(4):0-520

传统聚类方法大都是基于空间位置或非空间属性的相似性来进行聚类,分裂了空间要素固有的二重特性,从而导致了许多实际应用中空间聚类结果难以同时满足空间位置毗邻和非空间属性相近。然而,兼顾两者特性的空间聚类方法又存在算法复杂、结果不确定以及不易扩展等问题。为此,本文通过引入直接可达和相连概念,提出了一种基于双重距离的空间聚类方法,并给出了基于双重距离空间聚类的算法,分析了算法的复杂度。通过实验进一步验证了基于双重距离空间聚类算法不仅能发现任意形状的类簇,而且具有很好的抗噪性。  相似文献   

Optimization of nonconventional wells under uncertainty using statistical proxies     

Vincent Artus  Louis J. Durlofsky  Jérôme Onwunalu  Khalid Aziz 《Computational Geosciences》2006,10(4):389-404

The determination of the optimal type and placement of a nonconventional well in a heterogeneous reservoir represents a challenging optimization problem. This determination is significantly more complicated if uncertainty in the reservoir geology is included in the optimization. In this study, a genetic algorithm is applied to optimize the deployment of nonconventional wells. Geological uncertainty is accounted for by optimizing over multiple reservoir models (realizations) subject to a prescribed risk attitude. To reduce the excessive computational requirements of the base method, a new statistical proxy (which provides fast estimates of the objective function) based on cluster analysis is introduced into the optimization process. This proxy provides an estimate of the cumulative distribution function (CDF) of the scenario performance, which enables the quantification of proxy uncertainty. Knowledge of the proxy-based performance estimate in conjunction with the proxy CDF enables the systematic selection of the most appropriate scenarios for full simulation. Application of the overall method for the optimization of monobore and dual-lateral well placement demonstrates the performance of the hybrid optimization procedure. Specifically, it is shown that by simulating only 10% or 20% of the scenarios (as determined by application of the proxy), optimization results very close to those achieved by simulating all cases are obtained.  相似文献   

分形在储层参数井间预测中的应用   总被引：2，自引：0，他引：2  

陈克勇  张哨楠  邓礼正  胡永章 《新疆地质》2005,23(4):413-416

现有地震资料难以实现储层薄层的预测，分形理论的引入，可弥补这一不足．以具有连续性和等间距采样点的测井资料为基础，以分形分析理论为手段，结合生产实际进行了研究．根据分形地质统计学中对储层参数的研究，得出其分形理论模型，并通过VisualBasic语言编程，在计算机上实现了某地区4口井储层参数（包括孔隙度、渗透率和泥质含量）的井间预测，其结果达到了预期的效果，说明将分形理论用于储层参数井间预测具有可行性．  相似文献   

沁水盆地煤层气钻井工艺方法   总被引：1，自引：1，他引：1  

李云峰 《中国煤田地质》2005,17(6):52-53,70

针对沁水盆地煤层气概况,地层情况及开采条件,介绍了参数井、生产井、多分支地面煤层气水平开发井、丛式井等钻井工艺、钻具组合、井身结构及井身质量要求.  相似文献   

华容县注滋口大桥12#墩钻孔灌注桩成井措施与施工实践     

明邵军 《湖南地质》2002,21(3):207-210

华容县注滋口大桥12#墩钻孔灌注桩工程条件极差，经多种方法试验，最后采用了经济合理的冲击与回旋相结合的处理措施，成功地解决了上部大厚度、大体积的块石层及下部砂砾层整体失稳等技术难题。  相似文献