基于SOM和PSO的非监督地震相分析技术   总被引：5，自引：2，他引：3       下载免费PDF全文

张  郑晓东  李劲松  路交通  曹成寅  隋京坤 《地球物理学报》2015,58(9):3412-3423

地震相分析技术是储层预测的一种重要方法,可以用来描述有利沉积相带的分布规律.传统的地震相聚类分析方法对大数据的处理运算速度较慢,且容易陷入局部极小值,造成聚类分析的结构不准确.本文提出基于自组织神经网络(SOM)和粒子群优化方法(PSO)相结合的地震相分析技术,利用自组织神经网络能够保持原始地震数据的拓扑结构特性的特点,将大量冗余样本压缩为小样本数据,再通过粒子群的全局寻优能力改善K均值聚类的效果.理论模型和实际应用表明该方法能既有效实现数据压缩,又能提供较为准确的全局解,在地震相预测中兼顾计算效率和计算精度.  相似文献   

地震偏移反演成像的迭代正则化方法研究   总被引：12，自引：7，他引：5       下载免费PDF全文

王彦飞  杨长春  段秋梁 《地球物理学报》2009,52(6):1615-1624

利用伴随算子L^*,直接的偏移方法通常导致一个低分辨率或模糊的地震成像.线性化偏移反演方法需求解一个最小二乘问题.但直接的最小二乘方法的数值不稳定,为目视解译带来困难.本文建立约束正则化数学模型,研究了地震偏移反演成像问题的迭代正则化求解方法.首先对最小二乘问题施加正则化约束,接着利用梯度迭代法求解反演成像问题,特别是提出了共轭梯度方法的混合实现技巧.为了表征该方法的可实际利用性,分别对一维,二维和三维地震模型进行了数值模拟.结果表明该正则偏移反演成像方法是有效的,对于实际的地震成像问题有着良好的应用前景.  相似文献   

Calibration and uncertainty analysis of the SWAT model using Genetic Algorithms and Bayesian Model Averaging   总被引：4，自引：0，他引：4  

Xuesong Zhang  Raghavan Srinivasan  David Bosch 《Journal of Hydrology》2009,374(3-4):307-317

In this paper, the Genetic Algorithms (GA) and Bayesian Model Averaging (BMA) were used to simultaneously conduct calibration and uncertainty analysis for the Soil and Water Assessment Tool (SWAT). In this combined method, several SWAT models with different structures are first selected; next GA is used to calibrate each model using observed streamflow data; finally, BMA is applied to combine the ensemble predictions and provide uncertainty interval estimation. This method was tested in two contrasting basins, the Little River Experimental Basin in Georgia, USA, and the Yellow River Headwater Basin in China. The results obtained in the two case studies show that this combined method can provide deterministic predictions better than or comparable to the best calibrated model using GA. The 66.7% and 90% uncertainty intervals estimated by this method were analyzed. The differences between the percentage of coverage of observations and the corresponding expected coverage percentage are within 10% for both calibration and validation periods in these two test basins. This combined methodology provides a practical and flexible tool to attain reliable deterministic simulation and uncertainty analysis of SWAT.  相似文献   

Application of GA in optimization of pore network models generated by multi-cellular growth algorithms     

Saeid Jamshidi  Ramin Bozorgmehry Boozarjomehry  Mahmoud Reza Pishvaie 《Advances in water resources》2009

In pore network modeling, the void space of a rock sample is represented at the microscopic scale by a network of pores connected by throats. Construction of a reasonable representation of the geometry and topology of the pore space will lead to a reliable prediction of the properties of porous media. Recently, the theory of multi-cellular growth (or L-systems) has been used as a flexible tool for generation of pore network models which do not require any special information such as 2D SEM or 3D pore space images. In general, the networks generated by this method are irregular pore network models which are inherently closer to the complicated nature of the porous media rather than regular lattice networks. In this approach, the construction process is controlled only by the production rules that govern the development process of the network. In this study, genetic algorithm has been used to obtain the optimum values of the uncertain parameters of these production rules to build an appropriate irregular lattice network capable of the prediction of both static and hydraulic information of the target porous medium.  相似文献   

A mixed continuous and discrete nonlinear constrained algorithm for optimizing ship hull structural design     

Oscar B. Augusto  Alexandre Kawano 《Ocean Engineering》1998,25(9):793-811

A nonlinear search algorithm for optimizing constrained design of ship structures is presented. The decision variables can be continuous or discrete and the constraints can be homogeneous or inequality nonlinear functions of those variables. The algorithm does not use gradients; therefore, it can work with non-systematized functions such as tables or another class of design routine. It was tested in the structural design of a Patrol Boat and has proved to be a powerful tool decreasing the time expended in preliminary design when it is done by the conventional spiral approach.  相似文献   

On an inverse problem of ship-induced internal waves   总被引：1，自引：0，他引：1  

E. Avital  T. Miloh 《Ocean Engineering》1998,26(2):99-110

An inverse problem for trapped internal waves is considered in an attempt to provide a practical tool for estimating the density stratification in the sea from the wake pattern behind a moving vessel. The ambient stratification is represented by Barber's (1993) exponential series and the coefficients are found by matching the first mode dispersion relation to the one found from the wake data. A fast algorithm for calculating the dispersion relation is derived. It is shown that when the series converges with a low number of coefficients, the inverse profile is adequate, as happens for example for typical sea loch profiles. In more general circumstances the predicted maximum stratification still provides a reasonable approximation as a result of Barber's (1993) theorem.  相似文献   

结合PCA、多尺度分割及SVM的ASTER遥感蚀变信息提取     

唐淑兰  曹建农  王凯 《遥感学报》2021,25(2):653-664

为了利用遥感影像进行更加精确的找矿预测,本文选择新疆东天山尾亚地区ASTER数据进行矿化蚀变信息提取方法研究。为了提高信息提取精度,本文提出了结合主成分分析(PCA)、多尺度分割和支持向量机(SVM)的遥感矿化蚀变信息提取方法。首先,分析ASTER数据的特征,选取各矿化蚀变信息的特征波段,对组合波段进行主成分分析,获得主分量图像;然后,对各主分量图像进行多尺度分割,并获得分割之后的均值图像;接着,提取训练样本,利用SVM对训练样本进行训练,采用试验方法求得最优核参数和松弛变量,构造最优SVM模型;最后,运用最优SVM模型完成矿化蚀变信息的提取。进行主成分分析时,铁染蚀变信息选择Band1、2、3、4组合,Al-OH基团蚀变信息选择Band 1、4、6、7组合,OH和CO32-基团蚀变信息采用Band 1、2、8、9组合。在运行SVM时采用了序列最小优化算法(SMO)进行求解,速度提高了12%。实验结果表明,与波段比值法、主成分分析法及基于光谱角和SVM的方法等3种方法相比,本文方法提取铁染蚀变信息、Al-OH基团蚀变信息及OH和CO32-基团蚀变信息的总体精度可达到87.98%、 90.01%及88.93%,Kappa系数分别为0.8011、0.8134及0.8023,与成矿区带、已知矿点和已有不同地质背景成矿特征相关性较好。  相似文献   

3D Seismic survey design using mixed-radix based algorithm inversion     

Atahebson B. Santos  Milton J. Porsani  Manuelle S. Góis 《Geophysical Prospecting》2019,67(7):1720-1731

The determination of three-dimensional geometry and acquisition parameters, the seismic acquisition survey design, is constantly subject of studies in obtaining data with the highest seismic quality, operational efficiency and cost minimization. In this paper, we propose a methodology for inverting geometry parameters of three-dimensional orthogonal land seismic surveys based on a direct search method using a mixed-radix based algorithm. In this algorithm, the search space is discretized on a mixed-radix base, which depends on the extreme values and the search resolution of each parameter. We will show how to reparametrize the orthogonal acquisition geometry elements in order to obtain the independents and integers parameters that are necessary to construct the mixed-radix base. For the optimization purpose, we define an objective function to contemplate target parameters associated with the elements of the acquisition geometry directly related to the geophysical and operational constraints. Taking in account that the mathematical functions and the objective function we define for the problem have no significant computational cost, all model space parameters are fast and efficiently tested. We applied the algorithm, using as input data, provided by a one-line roll orthogonal reference geometry, assuming a pair of geological objectives as shallow and deep targets. All selected models that meet both the proposed objectives and the constraints are organized by decreasing order of fitness so that with the mixed-radix inversion algorithm we found not only the best model, but also a set of suitable models. Likewise, with the best set of geometries, it is possible to establish a direct comparison between them, analysing their adherence to the technical and operational requirements according to the availability and degree of detail of each one. We show the top 10 best results as a table, allowing a direct comparison between all aspects of these geometries, and we summarize the results showing graphically the fitness of all selected geometries and the inverted geometry elements for the 1000 best geometries. These graphical displays provide a direct way to understand how each model behaves as the fitness decreases. The algorithm is very flexible and its application can be extended to any environment and type of acquisition geometry, and in any phase study of an area be it regional, exploratory or development.  相似文献   

Optimizing compaction calculation for improved probabilistic 2D mapping     

Olena Babak  Kun Liu  Jeremy Gallop 《Geophysical Prospecting》2019,67(3):595-608

Integration of all available data in reservoir characterization is critically important. 2D mapping is a reliable and robust technique that allows integration of multiple secondary data, including geological and geophysical surfaces and maps, to generate realistic summaries of reservoir quality at each location in an area of interest with an associated measure of uncertainty. This is achieved in 2D mapping with a more straightforward implementation, requiring significantly less time and fewer resources than three-dimensional modelling. In this paper, we propose an approach for the empirical calculation and optimization of differential compaction maps by leveraging existing well control for the use in 2D mapping. Success of the proposal is demonstrated through tests of accuracy, precision and fairness of the local uncertainty distributions for 100 new stratigraphical wells drilled in the Christina Lake and Kirby East area.  相似文献   

气象条件对蜜脆苹果品质的影响          下载免费PDF全文

马玉平  吾米提.居马太  丛桂芝  冯岷华  祖农.阿比提 《沙漠与绿洲气象(新疆气象)》2021,15(5):139-143

根据伊犁州林业科学研究院2013—2019年分别从5个县不同的果园采样的品质检测资料,结合相应站点的气象资料,运用数理统计方法,研究了气象因子对蜜脆苹果主要品质构成因子(果实大小、可溶性固形物、酸度、果实硬度)的影响,从影响要素上来看,气温、降水、日照时数和相对湿度是影响蜜脆苹果品质最主要的气象因子,影响时段主要集中在5～9月。  相似文献