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1.
Sand temper compositions of regionally distinct Hohokam pottery sherds were determined by detailed point counts using sedimentary petrographic methods. Different temper compositions from different sites were compared with maps of sand composition zones within the geographic range of the pottery in order to establish the probable provenance of each sherd. A number of probable instances of intraregional pottery exchange were identified. The larger number of sand sources in undecorated vs. decorated pottery at each site suggests that undecorated pottery was made in more places than decorated vessels, and may have been traded differently as well. Petrographic analysis of temper is a useful method for studying exchange of homogeneous pottery in geologically diverse areas, and for investigating prehistoric Hohokam interaction in the Tucson and Red Rock Basins on a scale not possible with traditional archaeological techniques.  相似文献   

2.
王林松  陈超  杜劲松  王秋革  孙石达 《地球科学》2014,39(11):1607-1616
通过对我国大型水库蓄水的时空特征进行深入分析, 统计得到近60年来大型水库蓄水累积的库容量已达到697km3, 占全国所有水库库容量的83.3%及全球库容量的6.5%;而2000年以来的大型水库数量及蓄水量的变化有明显的加速, 库容量的变化率为16.7km3/a, 远高于1950年到2000年的4.9km3/a的增长率; 同时借助卫星重力(Gravity Recovery and Climate Experiment, GRACE)观测手段, 对2000年以后主要分布在长江流域以南地区的水库进行水储量估算, 结果显示GRACE仅能估算得到63%的水库变化量, 两者之间的差异可能反映了该地区地下水的长期变化. 结合大型水库的分布位置与库容量, 基于海平面变化方程计算得到了中国近海相对海平面的空间变化. 水库蓄水导致的渤海与东南沿海海域的相对海平面上升明显, 最大上升高度约为8mm; 而2000年以后的水库对海平面的影响主要集中在东南沿海, 其中南海海域较为突出, 上升高度约为2~3mm, 在此期间蓄水造成的近海不同验潮站位置的海平面增长速度在0.02~0.11mm/a之间变化.   相似文献   

3.
Dams and their reservoirs, constructed to manage the water scarcity problems of a region, sometimes lose whole or part of their functionality due to sedimentation. This issue, seen as a negative impact as far as reservoir life and its purpose is concerned, can be a boon to the construction industry, by providing a highly demanding construction material in the form of sand dredged from the reservoirs. Malampuzha reservoir, a multipurpose reservoir in the South Indian state of Kerala, is also losing considerable part of its storage due to siltation. This paper assesses the rate of sedimentation in Malampuzha reservoir, through bathymetric survey and suggests measures for utilization of the removable sediment. Our analysis has shown that the reservoir capacity is reduced from 226 to 205.19 Mm3; a reduction in capacity of 20.81 Mm3 in 55 years. The rate of sedimentation of the reservoir is estimated as 16.95 mm/year. The dead storage capacity of the reservoir has reduced to 47.5 % from the original at present. The composition of deposited sediments is also identified, based on which its productive use is recommended.  相似文献   

4.
In this study, the types of micropores in a reservoir are analyzed using casting thin section(CTS) observation and scanning electron microscopy(SEM) experiments. The high-pressure mercury injection(HPMI) and constant-rate mercury injection(CRMI) experiments are performed to study the micropore structure of the reservoir. Nuclear magnetic resonance(NMR), gas-water relative seepage, and gas-water two-phase displacement studies are performed to examine the seepage ability and parameters of the reservoir, and further analyses are done to confirm the controlling effects of reservoir micropore structures on seepage ability. The experimental results show that Benxi, Taiyuan, Shanxi, and Shihezi formations in the study area are typical ultra-low porosity and ultra-low permeability reservoirs. Owing to compaction and later diagenetic transformation, they contain few primary pores. Secondary pores are the main pore types of reservoirs in the study area. Six main types of secondary pores are: intergranular dissolved pores, intragranular dissolved pores, lithic dissolved pores, intercrystalline dissolved pores, micropores, and microfracture. The results show that reservoirs with small pore-throat radius, medium displacement pressure, and large differences in pore-throat structures are present in the study area. The four types of micropore structures observed are: lower displacement pressure and fine pores with medium-fine throats, low displacement pressure and fine micropores with fine throats, medium displacement pressure and micropores with micro-fine throats, and high displacement pressure and micropores with micro throats. The micropore structure is complex, and the reservoir seepage ability is poor in the study areas. The movable fluid saturation, range of the gas-water two-phase seepage zone, and displacement types are the three parameters that well represent the reservoir seepage ability. According to the characteristic parameters of microscopic pore structure and seepage characteristics, the reservoirs in the study area are classified into four types(Ⅰ–Ⅳ), and types Ⅰ, Ⅱ, and Ⅲ are the main types observed. From type Ⅰ to type Ⅳ, the displacement pressure increases, and the movable fluid saturation and gas-water two-phase seepage zone decrease, and the displacement type changes from the reticulation-uniform displacement to dendritic and snake like.  相似文献   

5.
Water reservoirs play an important role in areas with limited and erratic precipitation where water is stored and re-distributed later for different purposes. Irrigation is primarily a major water consumer in arid countries of Central Asia for the economic development, employment and food security of the region. The major rivers of Central Asia (e.g., Amu Darya, Syr Darya, and Zerafshan) are turbid watercourses. Sedimentation reduces the main reservoir asset i.e., its volume capacity. In addition, vast territories of the region’s countries have been transformed for agriculture to grow water intensive crops such as cotton, rice and wheat during the Soviet Union that dramatically accelerated soil erosion by water and wind. Thus, many man-made water reservoirs are affected by high sedimentation rates. Moreover, uneven spatial and temporal water resources and a Soviet-inherited unified hydraulic infrastructure have raised transboundary reservoir management issues over water resources allocation among the countries in the region such as Kyrgyzstan, Tajikistan, Kazakhstan, Uzbekistan and Turkmenistan. The rivers such as Syr Darya and Amu Darya are already regulated by more than 78 and 94 %, respectively and attempts for new reservoir projects upstream raises increased concerns of the downstream countries (e.g., the Rogun hydropower station in Tajikistan and the Toktogul reservoir in Kyrgyzstan). For instance, the uncoordinated use of reservoirs has caused the Arnasai lake problem in Uzbekistan with environmental, material damage and social unrest. The aim of this paper is first to review the present conditions and the role of man-made water reservoirs for irrigation in Central Asia with special focus on Uzbekistan, second to document past and current reservoir sedimentation conditions in Uzbekistan and third to discuss research carried out by Soviet and present-time local research community in the domain of erosion and sedimentation in the region.  相似文献   

6.
综合利用小水库群简易优化调度   总被引:3,自引:0,他引:3       下载免费PDF全文
朱颖元 《水科学进展》2001,12(3):390-394
提出一种以弃水量最小为目标函数的水库群简易优化调度方法──动态空库系数法。任一时刻某水库的空库系数反映该水库在该时刻的蓄水能力和供水能力。本法用时段初各水库空库系数的大小决定水库群的蓄放水次序,在满足约束条件下,时段末保持各水库的空库系数相等,由此尽可能地拦蓄径流,使弃水量最小。  相似文献   

7.
The lag-one serial correlation coefficient is one of the important hydrological metric used as a quantitative measure of carry-over capacity of water stored within a catchment. In this study, the annual lag-one serial correlation coefficient has been computed for 27 unregulated streams spread across the two main climatic regions of New Jersey, USA. The computed mean annual lag-one serial correlation coefficient was found to be 0.17, which is typical of the national value. It appears that streams that drain northern catchments have higher carry-over capacity in comparison to their southern counterparts. Further, the Goud–Dincer Gamma method of reservoir storage capacity was used to compare the average reservoir storage needed to meet the over-year storage requirement for a hypothetical reservoir located within the two main climatic regions. The results revealed that on average, a reservoir needed to meet over-year storage requirements in climate region 1 (northern New Jersey) needs to be a little more than one half times as large as those in climate region 2 (southern New Jersey) for the same level of regulation. Though groundwater recharge to streams in the southern catchments are generally higher than their northern counterparts, it appears relatively less ground water (release from storage) in any given year in the south is carried from the previous year(s).  相似文献   

8.
The objective of this paper is to estimate water seepage from the upper reservoir of Azad pumped storage power plant (PSPP), based on combined geotechnical investigations and geostatistical methods. Azad PSPP has been located in Sanandaj Province in Iran. In order to select the optimum water tightening alternative, such as clay blanket, concrete cover (or concrete lining), geomembrane, asphalt cover etc, estimation of water seepage from the reservoir is essential. Six exploratory boreholes were drilled at the pumped storage reservoir area and permeability tests (Lugeon tests) were conducted in all of them. Records at the boreholes have been considered as the main source for seepage calculations. Due to expansion of upper reservoir and a few boreholes, distribution of permeability and permeability changes in the reservoir area is not indicator of reservoir. In this research using geostatistical method (Kriging), lugeon values have been estimated for walls of reservoir. According to correspondence between estimated permeability distribution and geological conditions, the estimated values are acceptable. In addition results show that in about 60% of tests, permeability is very high and potential of water seepage is very high. Seepage was estimated for reservoir by using both analytical (vedernikov method) and numerical method. Results from both methods are very close and the average of seepage is around 280000 m3/day. From the results and general geological considerations, seepage is concentrated at fault zones. Results show that by using appropriate permeability distribution, the estimated values of water seepage are reliable. Due to the high amount of water seepage and economic importance of water in this region, water tightening is necessary.  相似文献   

9.
陕北地区延长组发育低(特)渗储层,除发育通常的高阻油层外,还极易形成低阻油层;因此,低阻油层的发现,极大拓宽了该区石油勘探和开发的领域。根据志丹油田樊川油区长61的石油地质特征,结合大量实验和生产数据资料的分析对比,对该区低阻油层的成因机理及宏观控制因素进行了分析。结果表明:长61储层的孔隙结构复杂导致束缚水饱和度增高,高地层水矿化度、高泥质含量及放射性砂岩的存在,是低阻油层得以形成的主要原因。通过大量实际试油和测井资料的对比可见,应用计算自然电位与自然电位曲线重叠法可以快速直观显示其含油性,声波时差-深电阻率的交会图与自然伽马-深电阻率交会图相结合可有效识别低阻油层。对区内85口探井进行了测井资料的二次解释,在长6发现了初次解释所遗漏的45个低阻油层,油层数由原来的117个增加到162个,净增27.8%。  相似文献   

10.
岩溶地区水库渗漏是碳酸盐岩地区兴建水利枢纽的主要工程地质问题之一,尤其是在可溶岩广布、岩溶发育强烈、地形复杂地区。拟建兴文县新坝水库地处岩溶地区,存在岩溶渗漏的可能性。通过对该水库库区地质概况、岩溶水系统进行分析研究,论证了水库潜在的三条岩溶渗漏途径均不会发生渗漏;并利用库区降雨量与泉流量进行水均衡计算,计算结果进一步论证了该水库不存在岩溶渗漏问题。  相似文献   

11.
山东临沂地区古生代复合热储成矿模式研究   总被引:1,自引:0,他引:1  
曹艳玲 《地质与勘探》2021,57(5):1136-1148
山东临沂地区地热资源丰富,前人对于临沂地区沂沭断裂带成热模式存在诸多争议。通过对研究区地热地质条件、地球物理特征和地热井数据进行综合研究,从地热产生的源、通、储、盖四要素进行分析,研究结果表明研究区地热成矿模式为古生代层状和带状复合热储地热成矿模式,断裂带为带状热储,断裂带周边稳定区域为层状热储。研究区热储为古生代砂岩,同时张性、张扭性断裂发育,导致热储为层状和带状的复合热储,较单一成因热储要复杂。对地热井数据归一化处理分析表明,盖层岩性及厚度对深部地热水温度存在较大影响,并且热储厚度对水温也存在影响,表现为表层有第四系覆盖的地热水温度,较无第四系覆盖的要高;盖层厚度越大,水温越高,热储厚度越大,水温也越高。这为进一步地热勘查与开采提供了理论指导。  相似文献   

12.
The Santa Cruz arroyo in the Tucson Basin, Arizona, has undergone major environmental changes over the last 8000 years. the Holocene stratigraphy along a 15 km segment of the arroyo, known as the San Xavier reach, which traverses the San Xavier Indian Reservation was investigated in detail. the Holocene alluvial sequence reveals that aggradation occurred until 8000 yr B.P. within a braided stream, was followed by a major period of channel erosion and widening from 8000 to 5500 yr B.P., which, in turn, was followed by vertical aggradation of the floodplain and five short periods of channel cutting. Broad climatic changes are correlated with major changes in the fluvial regime and landscape. However, the cycles of arroyo cutting and filling, during the semiarid climate of the last 2500 years, were probably the result of the creation of unstable internal geomorphic conditions, flooding, and human impacts on the floodplain. the alluvial history of the San Xavier reach has had a pronounced effect on the preservation and completeness of the archaeological record. Periods of erosion have created absences or gaps in the archaeological record and deep burial has removed some of the preserved archaeological remains from view. Environmental changes on the floodplain also influenced late prehistoric Hohokam settlement and subsistence patterns in the San Xavier region.  相似文献   

13.
地下水库作为一种“环保型水资源开发工程”越来越受到人们的关注,而目前建设的地下水库多以潜水含水层作为调蓄目标含水层。对于承压型地下水库的研究相对较少。定量化研究大气降水对承压型地下水库水资源调蓄的影响成为承压型地下水库规划建设的一个研究问题。本文在介绍地下水库及其水资源调蓄的基础上.以大庆市西部地下水库为例.运用地下水流数值模拟方法定量研究了大气降水对承压型地下水库水资源调蓄的影响程度。研究表明。大气降水对该地下水库水资源调蓄的影响很小.在进行地下水库调蓄运转模型的设计时。可将多年平均降水入渗补给量作为该地下水库库区所接受的大气降水入渗补给量。  相似文献   

14.
The exploration targets in the Kuqa Depression at present are mainly structure traps in Cretaceous-Tertiary. Due to the complexity of mountain distribution and reservoir forming conditions, the exploration of Jurassic in the eastern Kuqa Depression has been in a state of semi-stagnation since the discovery of the Yinan-2 gas reservoir. According to the concept and theory of “continuous petroleum reservoirs” and the re-analysis of the forming conditions of the Yinan-2 gas reservoir and regional natural gas in the eastern Kuqa Depression, it is believed that the deep Jurassic has good natural gas accumulation conditions as well as geological conditions for forming continuous tight gas reservoirs. The boundary of the Yinan-2 gas reservoir is not controlled by a structural spillpoint. The downdip part of the structure is dominated by gas, while the hanging wall of the fault is filled by water and forming obvious inverted gas and water. The gas reservoir has the normal temperature and ultra-high pressure which formed in the near source or inner-source. All of these characteristics indicate that the Yinan-2 gas reservoir is different from conventional gas reservoirs. The deep Jurassic in the eastern Kuqa Depression has multisets of source-reservoir-cap assemblages, which comprise interbedded sandstones and mudstones. These assemblages are characterized by a self-generation, self-preserving and self-coverage model. Reservoir sandstones and coal measure mudstones are interbedded with each other at a large scale. As the source rocks, Triassic-Jurassic coal measure mudstones distribute continuously at a large scale and can generate and expel hydrocarbon. Source rocks contact intimately with the overlying sandstone reservoirs. During the late stage of hydrocarbon expulsion, natural gas charged continuously and directly into the neighboring reservoirs. Petroleum migrated mainly in a vertical direction over short distances. With ultra-high pressure and strong charging intensity, natural gas accumulated continuously. Reservoirs are dominated by sandstones of braided delta facies. The sand bodies distribute continuously horizontal. With low porosity and low permeability, the reservoirs are featured by strong heterogeneity. It is hypothesized that the sandstones of the interior depression tend to be relatively tight with increasing depth and structure stress weakness. Thus, it is predicted that continuous tight gas reservoirs of ultra-high pressure may exist in the deep formations of the eastern and even the whole Kuqa Depression. So, it is worth evaluating the exploration potential.  相似文献   

15.
科学控制梯级水库蓄泄过程是减少旱灾损失的重要手段。以减少干旱年份流域缺水量和优化缺水时空分布为目标,构建应对干旱的梯级水库群多时空尺度协同优化调度模型。采用交互式与改进粒子群优化方法,外层寻求多年调节水库旱限水位最优控制,内层优化梯级水库群年内蓄泄过程,实现流域水资源年际调控、年内优化、库群协同、空间协调。以2014年的黄河流域重旱为例,通过模型优化提出2012—2014年龙羊峡水库旱限水位及梯级水库群年内蓄泄过程,结果表明:通过龙羊峡水库旱限水位控制实现跨年度补水,控制各年度缺水率在4.9%~5.7%之间,通过水库群出库过程优化控制不同区域各时段缺水均匀分布,将农业缺水率控制在7.0%~11.0%之间,显著减轻了旱灾损失。  相似文献   

16.
This work aims to reconstruct the burial history of various kinds of sandstones penetrated by the well YS201 in the Yaoyingtai region of the Changling Fault Depression, southern Songliao Basin, China. Analyses of fluid inclusions in the reservoir rocks, combined with a review of the regional tectonic evolution, revealed the hydrocarbon accumulation stage and accumulation age of the Early Cretaceous Denglouku group and the first member of the Quantou group reservoir, which are the future exploration focus for deep gas reservoirs in this region. Acoustic time data and sedimentary rates calculated for sediments in the YS201 well yielded thicknesses for the Yingcheng, Nenjiang, and Mingshui groups of 506, 539.18, and 144.85 m, respectively, thereby revealing the burial history of the sediments in the well. Fluid inclusions of the Denglouku group reservoir and the first member of the Quantou group reservoir contain oil inclusions and hydro-carbonaceous salt water inclusions. The main peaks of the homogenization temperature and salinity of these saltwater inclusions in the first member of the Quantou group reservoir are generally 110–120℃ and 6 wt % –8 wt %, respectively, and for the Denglouku group are 130–140℃ and 4 wt%–6 wt%. The data for both reservoirs show only one main peak, indicating that they both have experienced single-stage accumulation. Combining the homogenization temperature of the reservoir fluid inclusions with the burial and thermal history of the sediments in the YS201 well, we infer that the hydrocarbon gas in these two intervals accumulated at 79 Ma(middle Late Cretaceous).  相似文献   

17.
朱成涛 《水文》2017,37(3):48-52
根据长江防御洪水方案对雅砻江梯级水库的防洪库容预留要求,分析了预留防洪库容对梯级电站蓄水发电的影响。结合雅砻江水电开发的特点,提出了梯级水库防洪库容总量控制的解决思路,建立了基于防洪库容总量控制的蓄水期发电量最大模型,计算分析了9种不同来水情景的梯级水库优化蓄水方案,并给出了梯级水库总体优化蓄水策略。对该类问题研究具有一定借鉴意义。  相似文献   

18.
A multi-isotopic study of thermo-mineral waters from the Limagne Basin (French Massif Central) is reported. Lithium, B, Sr and Nd isotopic signatures in thermo-mineral waters and bedrocks were combined in order to determine the origin of these fluids from a reservoir point of view. Strontium and Nd isotopic systems showed that the thermo-mineral waters are mostly derived from a granitic reservoir type, with the exception of a few water samples having Sr and Nd isotopic signatures also reflecting a volcanic contribution (basalts). In a second step, Li and B isotopes were investigated, given that Li and B isotopic systematics are potentially affected by mass dependent fractionation during water/rock interaction and could provide some information on what takes place during this process. A great diversity of thermo-mineral waters within the Aigueperse area was clearly observed, which is directly related to the origin of these thermal waters in terms of reservoirs. These different geothermal reservoirs are characterized by different geological settings and intensity of water/rock interaction (i.e. depth and temperature).  相似文献   

19.
It is a common concern that the groundwater flow field caused by the Three Gorges Dam changes the regional seismic activity and environment. The changes in the seepage region could be effectively reflected through the analysis of the groundwater age using chlorofluorocarbons (CFC)-based techniques. In this study, the influences of the reservoir water on groundwater and the seepage region boundary of the reservoir were investigated using CFCs, stable isotopes, and water level in groundwater, reservoir water, and spring water during the water storage process of the Three Gorges Reservoir. The results show that the water supplied by the groundwater is older, whereas the water supplied by the reservoir and the springs is younger. With an increase in the water level of the reservoir, the water in well W3, which is located at the vice dam of the head region, becomes older due to the reservoir loading effect, whereas the water in well W4 become younger due to the lateral seepage of reservoir water. This finding indicates that the groundwater seepage regions in wells W3 and W4, which are located at upstream of the reservoir, are all influenced by the Three Gorges Reservoir. In contrast, the sampling points in the northern section of the Xiannvshan fault zone, which is farther from the dam, did not exhibit any direct hydraulic connection between the groundwater and the reservoir water; thus, the reservoir seepage effects may not affect the northern part of the Xiannvshan fault zone. These research results provide important reference data that can be used to analyze the effects of the Three Gorges reservoir storage on the regional environment.  相似文献   

20.
龙羊峡水库水温结构演变及其对下游河道水温影响   总被引:1,自引:0,他引:1       下载免费PDF全文
多年调节水库由于年际运行过程的差异引起水库水温结构变化,探明其规律及对下游河道水温响应具有重要意义。以黄河龙羊峡水库为研究对象,利用水库蓄水后的1988~2008年运行过程及水温观测资料,分析了水库运行方式与水温结构变化关系,探讨了水库不同运用过程对下游河道水温的影响。研究结果表明:龙羊峡水库水温结构演变及其对下游河道水温影响程度与水库运用过程密切相关。12~3月,水温结构为弱分层或等温分布,较高水位的蓄热增温效应明显,下游河道水温与水库水位变化具有同相位关系;5~10月,水温结构为分层分布,水位是决定分层形态变化最主要因素,下游河道水温与水库水位变化具有反相位关系,同时,水位与河道水温在不同的出入库水量条件下,呈现不同的线性相关关系。11月和4月,水温结构近乎为等温状态,也是水温结构变化的转折点。研究成果为分析大型水库在不同运行条件下水温结构及下游河道水温提供一定的参考依据。  相似文献   

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