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951.
Justyna K. Przybysz-Jarnut Remus G. Hanea Jan-Dirk Jansen Arnold W. Heemink 《Computational Geosciences》2007,11(1):73-85
A data assimilation method was applied to estimate poorly known parameters (permeabilities) in a numerical reservoir model.
Most variational methods for data assimilation are based on the assumption that the model is perfect except for the poorly
known parameters. The representer method allows also for model errors, i.e. for uncertainties in the state variables (pressures
and saturations). The method is based on minimizing a cost functional, assuming all the errors and parameters to be multivariate
Gaussian random variables with given mean and covariances. The uncertain parameters and variables are expanded into a finite
sum of basis functions called representers, and the gradients of the cost functional are obtained with an adjoint method.
This approach gives an optimal parametrization in the sense that the final result is equal to the solution of the full inverse
problem. The method was tested on a simple one-dimensional model to simulate two-phase (oil-water) flow through a heterogeneous
reservoir. The results show that the method is able to provide an acceptable estimate of the permeability field. We used pressure
measurements from a small number of observation wells in between the injection and production wells, but the representer method
could be used equally well to assimilate data from other sources. The method appears to be a promising data assimilation tool
for applications in reservoir engineering. 相似文献
952.
基于直线特征匹配的序列图像自动配准 总被引:2,自引:0,他引:2
提出了一种运用相应直线段特征作为控制基础的序列图像自动配准方法。根据相应直线段"共线"原理建立了图像配准模型,该模型的优点是不必精确定位相应直线段的端点,突破了相应特征必须严格"同名"的限制。同时,根据图像配准对控制直线段的要求,分别设计了序列图像中直线段特征的自动提取和自动匹配算法,从而实现了概略对准条件下的序列图像的全自动配准。 相似文献
953.
Mengnan Liu Hao Liu Antonius Johannes van Loon Jie Xu Shimeng Hao Yingzhao Zhang 《Sedimentology》2023,70(1):5-30
Based on high-quality two-dimensional seismic profiles and well data, the seismic reflection characteristics from the late Pliocene and Pleistocene succession of the Qiongdongnan Basin in the South China Sea have been analysed. The result will help in understanding the sedimentological development of slope areas. Twenty coeval clinothems are recognized and four major clinothem types are distinguished. In addition, three types of shelf-edge trajectories are recognized. The various parameters of the clinothems are analysed quantitatively and the relationships between the various clinothem types are studied in combination with the controlling roles. It is concluded that: (i) the shelf-edge trajectories are related to the type of clinothem; (ii) fluctuations in the relative sea level, in combination with variations in sediment supply, result in different clinothem types and geometric parameters; these parameters show interdependencies; (iii) the alternations of progradation and aggradation of clinothems may provide information of the relative sea level and changes in sediment supply; (iv) some lowstand fans could develop at the foot of the slope in the central–eastern part of the basin when the relative sea level started to fall or began to rise. The results of the present study are consequently significant for further quantitative analyses of the characteristics and development of the continental slope, not only in the Qiongdongnan Basin, but also in other basins. 相似文献
955.
Semantically aligning the heterogeneous geospatial datasets (GDs) produced by different organizations demands efficient similarity matching methods. However, the strategies employed to align the schema (concept and property) and instances are usually not reusable, and the effects of unbalanced information tend to be neglected in GD alignment. To solve this problem, a holistic approach is presented in this paper to integrally align the geospatial entities (concepts, properties and instances) simultaneously. Spatial, lexical, structural and extensional similarity metrics are designed and automatically aggregated by means of approval voting. The presented approach is validated with real geographical semantic webs, Geonames and OpenStreetMap. Compared with the well-known extensional-based aligning system, the presented approach not only considers more information involved in GD alignment, but also avoids the artificial parameter setting in metric aggregation. It reduces the dependency on specific information, and makes the alignment more robust under the unbalanced distribution of various information. 相似文献
956.
目前,废弃露天矿山的治理不仅需要消除地质灾害隐患,同时需要进行生态环境治理。滚石灾害是高陡边坡最易发生的地质灾害类型之一。在治理过程中,必须充分考虑滚石的弹跳高度和落点分布范围,同时合理运用台阶植被绿化等生态治理措施。以温州市平阳县鳌江镇荆溪山废弃矿山高陡边坡为例,通过对落石运动轨迹模拟分析,提出综合生态治理方案,为相关边坡生态治理提供参考。 相似文献
957.
准确、高效地获取地震资料的频率信息是时频技术的关键。目前最热门的匹配追踪算法相比常用的小波变换和广义S变换来说,具有更高的时频分辨率和局部自适应性,能同时在时间域和频率域获得较准确的定位,提取较准确的频率域信息,为地震属性研究、油气检测等研究工作服务。RGB色彩融合技术是一种显示技术,它可以将多个频率体分为低、中、高三个频带进行融合显示,全面地反映各频带信息,弥补单一属性包含信息较少的缺点。将采用匹配追踪的RGB色彩融合技术应用于实际地震资料,清楚地刻画了河道的边界,并对河道内部的非均质性有一定程度的反映,较常规属性具有更深刻的意义。 相似文献
958.
959.
针对基于最近邻距离比率约束和几何条件约束的影像特征匹配方法,在处理重复纹理影像以及视角和尺度变化大的宽基线影像时,存在匹配正确率低和匹配点对数量少的问题,设计了结合运动平滑约束与核线约束的AKAZE特征匹配提纯算法。①为提高影像特征的不变性、显著性和时效性,采用AKAZE算子提取影像特征,经暴力匹配快速构建初始匹配集;②基于网格运动统计区分真假匹配,剔除不能满足运动平滑约束的匹配点对;③为消除局部相似特征引起的误匹配,采用核线约束提高匹配纯度。实验结果表明:所提算法实现了重复纹理影像、倾斜影像和宽基线影像同名点对的高精度匹配,增加了匹配点对数量,拓展了特征匹配的适用范围。 相似文献
960.