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孙一男 《地震地磁观测与研究》2022,43(2):219-224
人工地震数据的存储管理及共享技术发展迅速,但是存储管理方式、资源利用率及服务水平等还有很大的提升空间。针对以上问题初步建立人工地震数据平台,利用Web和数据库技术,整合并存储已有人工地震数据资源,以便向公众及地震科研人员提供最新工作进展和研究成果。该平台的建立,利于科学研究工作的交流合作和观测资料的充分利用,从而为我国防震减灾事业做更大贡献。 相似文献
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对于致密砂岩储层而言,渗透率是评价储层物性、渗流特征的重要参数,也是储层产能挖潜和提高采收率的关键.致密砂岩储层孔隙类型多样,孔隙结构复杂,非均质性强,孔渗关系变化复杂,并非简单的线性关系.利用孔渗统计回归和测井解释方法预测精度较低,致密砂岩储层渗透率预测成为一项重要而艰巨的任务.本研究基于孔喉结构是致密砂岩储层渗透率的主控因素,重点利用毛管压力(MICP)、核磁共振(NMR)、岩心物性实验数据及测井资料,对基于统计回归理论、流体流动单元划分(FZI)储层分类理论、分形几何理论及人工智能理论的渗透率预测方法进行综述.最后指出,基于MICP、NMR及常规测井,将流体流动单元划分(FZI)储层分类技术、分形几何数字岩心技术以及人工智能机器学习技术相结合,可形成一套具有岩石物理学意义的致密砂岩储层渗透率评价和预测的有效方法. 相似文献
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Zhang Zhifu Meng Xiaohong Liu Hong Chen Jingbo Li YouMing 《应用地球物理》2006,3(4):218-225
An accurate and wide-angle one-way propagator for wavefield extrapolation is an important topic for research on wave-equation prestack depth migration in the presence of large and rapid velocity variations. Based on the optimal separable approximation presented in this paper, the mixed domain algorithm with forward and inverse Fourier transforms is used to construct the 3D one-way wavefield extrapolation operator. This operator separates variables in the wavenumber and spatial domains. The phase shift operation is implemented in the wavenumber domain while the time delay for lateral velocity variation is corrected in the spatial domain. The impulse responses of the one-way wave operator show that the numeric computation is consistent with the theoretical value for each velocity, revealing that the operator constructed with the optimal separable approximation can be applied to lateral velocity variations for the case of small steps. Imaging results of the SEG/EAGE model and field data indicate that the new method can be used to image complex structure. 相似文献
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跨孔电磁层析技术对桥墩溶岩洞的探测 总被引:2,自引:0,他引:2
郭贵安 《CT理论与应用研究》2001,10(1):44-51
肇庆大桥位于西江流域,是连接肇庆和珠江三角洲地区的主要干线上的大桥。5个主桥墩位于溶洞和断层破碎带上,以往常用的单桩单孔的方法只能查有10cm直径垂直下方的溶洞分布情况,这种常规的方法难于查明整个桥墩位下方的溶洞分布情况,而且一孔之见难于达到技术要求。近年来发展起来的CT成像技术,正好可以弥补这方面的不足。本次电磁波CT探测法在肇庆大桥5个主桥墩的溶洞探测结果说明,这种方法是可行的,溶洞探测结果还经过最后的钻桩验证。 相似文献
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In this paper, the changes in sediment transport over 51 years from 1955 to 2006 in the Kuye River in the Loess Plateau in China are assessed. Key factors affecting sediment yield and sediment transport, such as precipitation depth, discharge, and human activities are studied. To investigate the changes in sediment yield in this watershed, a trend analysis on sediment concentration, precipitation depth, and discharge is conducted. Precipitation depths at 2 Climate Stations (CSs), as well as discharge and sediment transport at 3 Gauging Stations (GSs) are used to assess the features of sediment transport in the Kuye River. The rtmoff modulus (defined as the annual average discharge per unit area, L/(s·km^2)) and the sediment transport modulus (defined as the annual suspended sediment transport per unit area, t/(yr km^2)) are introduced in this study to assess the changes in runoff and sediment yield for this watershed. The results show that the highest average monthly discharge during the study period in the Kuye River is 66.23 m^3/s in August with an average monthly sediment concentration of 88.9 kg/m^3. However, the highest average monthly sediment concentration during the study period in the Kuye River is 125.34 kg/m^3 and occurs in July, which has an average discharge of 42.6 m^3/s that is much less than the average monthly discharge in August. It is found that both the runoff modulus and sediment transport modulus at Wenjiachuan GS on the Kuye River has a clear downward trend. During the summer season from July to August, the sediment transport modulus at Wenjiachuan GS is much higher than those at Toudaoguai and Longmen GSs on the Yellow River. The easily erodible loess in the Kuye River watershed and the sparse vegetation are responsible for the extremely high sediment yield from the Kuye River watershed. The analyses of the grain size distribution of suspended load in the Kuye River are presented. The average monthly median grain size of suspended load in the Kuye River is largest in February and then decreases until June. In July, the average monthly median grain size of suspended load approaches another peak and decreases until September. Then, the median grain size of suspended load starts to increase until February of the following year. However, the average monthly median grain size of suspended load in the Yellow River at Toudaoguai and Longmen GSs is the smallest between early summer and late fall The median grain size in the Yellow River starts to increase in November and approaches the largest size in January. 相似文献
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3He/4He ratios up to 3.5 times the ratio of atmospheric He were found in groundwater samples. The3He enrichment can be attributed to radiogenic3He produced by in-situ beta-decay of3H. This shows that tritiogenic3He is accumulating in confined waters. From tritiogenic3He and3H concentrations, ages of groundwaters can be calculated. Detection of tritiogenic3He gives a tool to trace a tritium contamination which occurred in the past and cannot be assessed only by the3H counting method. 相似文献
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Observations of trace gases (SO2, NH3, NO2 and O3) were made during the period 1981 to 1984 at 6 different locations representative of urban industrial, urban, nonurban, thermal power plant and marine environment. Diurnal variations of the trace gases were studied in an urban environment. Except in the urban industrial environment, the concentration of NH3 was found in the range of background values. Also, the average concentrations of NO2 and O3 at the different environments were in the order of background values. However, the concentrations of SO2 were substantially higher by about 7 times, in urban industrial and thermal power plant environments. The diurnal variations of SO2, NH3 and NO2 showed anitphase relationship with surface temperature at the urban environment station which is relatively free of industrial pollution. Discussion is centred on trace gas variations in different environments in India together with the values reported for various countries in the world. 相似文献
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The aim of this study is to estimate likely changes in flood indices under a future climate and to assess the uncertainty in these estimates for selected catchments in Poland. Precipitation and temperature time series from climate simulations from the EURO-CORDEX initiative for the periods 1971–2000, 2021–2050 and 2071–2100 following the RCP4.5 and RCP8.5 emission scenarios have been used to produce hydrological simulations based on the HBV hydrological model. As the climate model outputs for Poland are highly biased, post processing in the form of bias correction was first performed so that the climate time series could be applied in hydrological simulations at a catchment-scale. The results indicate that bias correction significantly improves flow simulations and estimated flood indices based on comparisons with simulations from observed climate data for the control period. The estimated changes in the mean annual flood and in flood quantiles under a future climate indicate a large spread in the estimates both within and between the catchments. An ANOVA analysis was used to assess the relative contributions of the 2 emission scenarios, the 7 climate models and the 4 bias correction methods to the total spread in the projected changes in extreme river flow indices for each catchment. The analysis indicates that the differences between climate models generally make the largest contribution to the spread in the ensemble of the three factors considered. The results for bias corrected data show small differences between the four bias correction methods considered, and, in contrast with the results for uncorrected simulations, project increases in flood indices for most catchments under a future climate. 相似文献
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Cu concentrations in surface (river and lake) and subsurface waters are determined. The geographic pattern of Cu distribution in natural water is identified. This pattern is controlled by the difference between its concentrations in drained rocks and soils and the geochemical redox conditions of its migration. Territories with low, medium, and elevated Cu concentrations in natural waters are identified. The concentrations of Cu in natural waters of the region are found to be generally lower than the Clarke values. 相似文献
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Changes in thermal extremes of the climate of Poland in 1951–2010 are examined. Warm extremes have become more frequent, while cold extremes have become less frequent. In the warming climate of Poland, the increase in the number of extremely warm days in a year and the decrease in the number of extremely cold days in a year have been observed. Also the increase of the maximum number of consecutive hot days in a year and the decrease of the maximum number of consecutive very cold and extremely cold days in a year have been observed. However, the trends are not of ubiquitous statistic significance, as the natural variability is strong. 相似文献
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M. MONIRUL QADER MIRZA 《水文科学杂志》2013,58(5):613-631
Abstract The basin area of the Ganges River in Bangladesh is extremely dependent on a regular water supply from upstream to meet requirements for agriculture, fisheries, navigation, salinity control, and domestic and industrial sectors. In 1975, India commissioned a barrage on the Ganges River at Farakka to divert a significant portion of the dry season flow in order to make the Calcutta Port navigable. Statistical analyses of discharge and water level data have been carried out to determine if significant changes have occurred in the hydrology of the Ganges system in Bangladesh in the post-Farakka period. Siltation of the Gorai River (an offtake of the Ganges River) has also been examined using the stage-discharge relationship and regression analysis. The analyses show that the diversion has caused considerable hydrological changes in the Ganges system in Bangladesh. The water supply in the dry season has been reduced substantially, while siltation of the Gorai River has increased significantly. 相似文献
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