Problems in space-time kriging of geohydrological data   总被引：6，自引：0，他引：6  

Shahrokh Rouhani  Donald E. Myers 《Mathematical Geology》1990,22(5):611-623

Spatiotemporal variables constitute a large class of geohydrological phenomena. Estimation of these variables requires the extension of geostatistical tools into the space-time domain. Before applying these techniques to space-time data, a number of important problems must be addressed. These problems can be grouped into four general categories: (1) fundamental differences with respect to spatial problems, (2) data characteristics, (3) structural analysis including valid models, and (4) space-time kriging. Adequate consideration of these problems leads to more appropriate estimation techniques for spatiotemporal data.  相似文献   

下地幔侧向不均匀及绝对板块运动对大地水准面的影响     

李金文  管泽霖 《武汉大学学报(信息科学版)》1991,(2)

本文提出并研究了板块上大地水准面受下地幔侧向不均匀性及板块绝对运动的影响而随时间变化的问题。利用已有的下地幔侧向不均匀性模型、板块绝对运动速度模型进行了计算,并分核幔边界不存在起伏和存在起伏两种情况进行了讨论。结果表明,在相当长时间内,其垂直变化绝对幅度可达 200米。确定古大地水准面应考虑这一变化。  相似文献   

Research advances,geological implication and application in Ordos Basin of the “pore-size controlled precipitation” in diagenesis of carbonate rock reservoir     

Sheng Hui  Duan Zheng-Ming  Liu Shan-Wei  Zeng Zhe  Feng Jian-Wei 《古地理学报》1999,22(4):744-760

Based on the discovery of pore-size controlled mineral precipitation and cementation heterogeneity in carbonate rock reservoirs,the state of art and the geological implications are summarized,referring to the fluid-rock interaction and chemical hydrodynamics in porous media. (1)The pore-size controlled precipitation phenomenon is common in geological environments,as shown by the heterogeneous cementation and eventual features that the large pores are filled while small pores can be preserved. Related studies are mainly divided into three aspects,including pore structure observations at different scales,numerical simulation of fluid-rock interaction and mineral precipitation experiment. (2)The kinetic models related to surface chemistry can be used to explain the heterogeneous precipitation affected by pore-size distribution. The larger interfacial tension and mineral crystal curvature in the micropores result in the much higher effective solubility.Thus the fluids in micropores can maintain a higher supersaturation with no minerals precipitation. (3)The pore-size controlled precipitation leads to the selective preservation of micropores. It means that the much larger pores tend to be cement-filled while the smaller pores are preserved in the case of coexistence of pores at different scales. The impacts of cementation types on the overall permeability of rock are different. The pore-size controlled precipitation phenomenon is also worthy of attention in the research of geothermal development and geologic sequestration of carbon dioxide. In the last part, based on the heterogeneous cementation and porosity distribution of the Majiagou Formation in the Ordos Basin,we study the impacts of diagenetic fluids properties,origin and cementation patterns on the evolution of pore structure and high-quality reservoir distribution.The discovery and emphasis of pore-size controlled precipitation is of great theoretical significance to our understanding of the complex fluid-rock interaction process,which provides a new perspective for reservoir diagenesis and pore preservation.  相似文献   

The broad-band fractal nature of heterogeneity in the upper crust from petrophysical logs   总被引：2，自引：0，他引：2  

Sean Dolan  Christopher Bean  & Bruno Riollet 《Geophysical Journal International》1998,132(3):489-507

  相似文献   

北堡油田中区东营组储层非均质性研究   总被引：5，自引：0，他引：5  

杨少春  王志欣  周海民 《高校地质学报》1998,(3)

储层非均质性包括微观和宏观非均质性。通过对岩心薄片、铸体薄片、电镜、Ｘ－衍射等试验数据以及测井储层评价数据分析,揭示冀东北堡油田中区东营组储层非均质特征为：储层岩石成分复杂,不稳定组分含量高,分选差,含泥沙质结构;压实作用、溶蚀作用及粘土矿物转化现象普遍,成岩变化大;中小孔细喉结构,连通性差,微观非均质性强。宏观非均质性较强,层内纵向上渗透率差异明显,渗透率非均质参数值较大;层间非均质程度与层内的相近;平面非均质性强,砂体连通性差,有效砂层系数较小,非均质参数在平面上变化大。采用压裂措施,降低储层非均质性,改善储层连通性,可提高开发效果。  相似文献   

A Spatial-Temporal/3-D Model for Volcanic Hazard Assessment: Application to the Yucca Mountain Region, Nevada     

Chih-Hsiang Ho  Eugene I. Smith 《Mathematical Geology》1998,30(5):497-510

We present a 3-D Poisson model that permits identification and quantification of volcanic phenomena distributed through space and evolving in time (i.e., spatiotemporal data). Specifically, the model: (1) is volcanologically informative in solving problems of volcanic risk/hazard which depends on the location and time of future events; (2) contains model fitting computation algorithms that are efficient; and (3) is flexible enough to handle a large class of volcanic risk/hazard studies. Furthermore, we apply the model fitting techniques developed in this paper to the volcanic data from the Yucca Mountain project to demonstrate a unified volcanic hazard analysis. This study also evaluates the sensitivity of the statistical models developed by experts who have addressed the volcanic hazard/risk assessment problem near the Yucca Mountain region.  相似文献   

Application of the time-frequency polarization analysis to study the complexity of surface wave propagation     

Hong Chen  Zhong-Xian Huang 《地震学报(英文版)》1998,11(2):171-178

A new technique called the time-frequency polarization analysis was introduced in this paper. The technique combined the traditional surface wave analysis techniques (moving window and multi-filter) with the singular value decomposition method to measure the incidence azimuth of surface waves with different wavelengths. It was applied to study the progagation paths of surface waves across the different blocks of Chinese continent and different zones of Qinghai-Xizang (Tibet) plateau. The results show that the method can make full use of the differences in frequency compositions and arrival times of different surface wave modes, and give better polarization analysis results. The analysis by actual data shows that the lateral heterogeneity of the lithospheric structure influences the propagation paths of surface waves severely. Deviations of the paths across the Qinghai-Xizang plateau from great circle paths are great. Deviations of the surface waves across the different zones in Qinghai-Xizang plateau are different. This project was sponsored by the Joint Earthquake Science Foundation.  相似文献   

生态空间理论及其在生物入侵研究中的应用   总被引：5，自引：1，他引：5  

周霞  张林艳  叶万辉 《地球科学进展》2002,17(4):588-594

生态空间理论（theoryofspat ialecology）是对生态系统空间关系进行研究的一种理论，主要包括尺度、空间格局和镶嵌动态等。模型是研究空间关系的重要手段，其中莱文斯（Levins）模型、细胞自动机（cel lularautomata）模型和反应-扩散（React ion Di f fusion）模型是 3个基本的模型。尺度是生态学研究中的核心问题，对于不同的研究对象，应在相应的尺度上进行思考。空间异质性是不同尺度上的生态学过程的结果，同时它也影响各种生态学过程。随着人们对生物入侵的日益关注，空间生态学理论尤其是一些空间模型越来越多的应用于入侵和竞争的研究中。  相似文献   

A Numerical Study on Effects of Land-Surface Heterogeneity from “Combined Approach” on Atmospheric Process Part I: Principle and Method     

Zeng Xinmin  Zhao Ming  Su Bingkai 《大气科学进展》2000,17(1):103-120

1.IntroductionAnideallandsurfacemodelmustbothrealisticallydescribethelandsurfacecharacteristics(especiallytheuniversalheterogeneity)andbecomputationallyinexpensive.CurrentlyPOpularlandsurfacemodelsareallbasedon"bigfeartheory,inwhichamodelgridcellisdividedintomanypatches(e.g.,abaresoilpatchoravegetationpatch;manyregularpatchesdividedintoaccordingtogeographicallocations),andinwhichonlyinterpatchvariabilityistakenintoaccountwhileseldomintrapatchvariabilityis,whentheheterogeneityisconsidered.Even…  相似文献   

社交网络时空大数据聚类挖掘有效选择分析     

张媛  胡庆武 《测绘地理信息》2020,(2):45-50

来自社交网络的时空大数据具有海量和高动态的特性,有效选择时空数据进行聚焦挖掘分析至关重要。以微博位置签到数据为例,首先,对时空大数据空间聚类挖掘的有效选择问题进行了研究,针对社交网络时空数据不确定性问题,提出了时空大数据针对聚类挖掘的有效选择方法。聚类挖掘有效选择方法提出从空间、时间或属性等维度对时空大数据进行分割。然后,对分割得到的数据集进行空间探索分析(exploratory spatial data analysis,ESDA),得到具有聚类挖掘潜力的数据集。最后,以武汉市微博位置签到数据进行商圈热点探测为例,对提出的社交网络时空大数据聚类挖掘有效选择方法进行验证。结果表明,有效选择方法可以得到挖掘效率和精准性更高的时空数据集。  相似文献