共查询到20条相似文献，搜索用时 31 毫秒
1.
动态模式匹配算法在地层对比中的应用 总被引：2，自引：0，他引：2
动态序列匹配算法已经被广泛地用于模式识别过程中。采用特殊的编码方法来模仿人眼的工作原理，对待识别信号与标准模式信号进行计算机自动匹配。从而达到识别未知信号的目的。针对利用测井曲线的地层对比，本文在动态匹配算法的基础上，为提高对比的可靠性，研究了以相似度S为主体，加上曲线的均值Y、曲线的方差σ、地层厚度△H以及作为改进参数—岩性特征值为辅助参数的匹配距离计算方法。按照最小匹配费用原则从匹配代价矩阵中确定了地层匹配路径。实际资料处理表明，该方法不仅能够较好找出匹配地层，还可有效判断地层尖灭现象。 相似文献
2.
Conditional Simulation with Patterns 总被引：17，自引：0，他引：17
An entirely new approach to stochastic simulation is proposed through the direct simulation of patterns. Unlike pixel-based
(single grid cells) or object-based stochastic simulation, pattern-based simulation simulates by pasting patterns directly
onto the simulation grid. A pattern is a multi-pixel configuration identifying a meaningful entity (a puzzle piece) of the
underlying spatial continuity. The methodology relies on the use of a training image from which the pattern set (database)
is extracted. The use of training images is not new. The concept of a training image is extensively used in simulating Markov
random fields or for sequentially simulating structures using multiple-point statistics. Both these approaches rely on extracting
statistics from the training image, then reproducing these statistics in multiple stochastic realizations, at the same time
conditioning to any available data. The proposed approach does not rely, explicitly, on either a statistical or probabilistic
methodology. Instead, a sequential simulation method is proposed that borrows heavily from the pattern recognition literature
and simulates by pasting at each visited location along a random path a pattern that is compatible with the available local
data and any previously simulated patterns. This paper discusses the various implementation details to accomplish this idea.
Several 2D illustrative as well as realistic and complex 3D examples are presented to showcase the versatility of the proposed
algorithm. 相似文献
3.
A method for multiscale parameter estimation with application to reservoir history matching is presented. Starting from a
given fine-scale model, coarser models are generated using a global upscaling technique where the coarse models are tuned
to match the solution of the fine model. Conditioning to dynamic data is done by history-matching the coarse model. Using
consistently the same resolution both for the forward and inverse problems, this model is successively refined using a combination
of downscaling and history matching until model-matching dynamic data are obtained at the finest scale. Large-scale corrections
are obtained using fast models, which, combined with a downscaling procedure, provide a better initial model for the final
adjustment on the fine scale. The result is thus a series of models with different resolution, all matching history as good
as possible with this grid. Numerical examples show that this method may significantly reduce the computational effort and/or
improve the quality of the solution when achieving a fine-scale match as compared to history-matching directly on the fine
scale. 相似文献
4.
In most multiple-point simulation algorithms, all statistical features are provided by one or several training images (TI) that serve as a substitute for a random field model. However, because in practice the TI is always of finite size, the stochastic nature of multiple-point simulation is questionable. This issue is addressed by considering the case of a sequential simulation algorithm applied to a binary TI that is a genuine realization of an underlying random field. At each step, the algorithm uses templates containing the current target point as well as all previously simulated points. The simulation is validated by checking that all statistical features of the random field (supported by the simulation domain) are retrieved as an average over a large number of outcomes. The results are as follows. It is demonstrated that multiple-point simulation performs well whenever the TI is a complete (infinitely large) realization of a stationary, ergodic random field. As soon as the TI is restricted to a limited domain, the statistical features cannot be obtained exactly, but integral range techniques make it possible to predict how much the TI should be extended to approximate them up to a prespecified precision. Moreover, one can take advantage of extending the TI to reduce the number of disruptions in the execution of the algorithm, which arise when no conditioning template can be found in the TI. 相似文献
5.
应用双相介质波动方程,推导了双相横向各向同性介质(TI)中波动方程的有限差分格式,对双相TI介质中弹性波有限差分数值进行了模拟.结果表明,弹性波在双相TI介质中传播时,除了存在常规的快纵波(qP1)和横波以外,还存在慢纵波( qP2).并且慢纵波的速度明显小于快纵波,而且受耗散系数的影响衰减地很快,所以在实际中很难观测到慢纵波.快纵波在固相和流相中相位相同,而慢纵波在固相和流相中的相位相反.慢纵波在流相中振幅大,而在固相中的振幅较小. 相似文献
6.
地层的自动分级对比技术 总被引：1，自引：0，他引：1
地层缺失和厚度不等是基于测井数据进行井间地层自动对比中需要解决的关键问题。融合聚类分析和动态波形匹配技术进行地层自动分级对比可以解决上述问题。利用聚类分析划分不同级别的层段。在高级别层段划分结果控制下 ,计算两井任何两个次级层段的累计最小“匹配代价” ,再反向追踪找出最佳匹配路径 ,从而获得最优的地层对比结果。利用这种动态波形匹配技术进行全局地层对比 ,使地层对比的可靠性增加。 相似文献
7.
基于GIS和背景数据知识的空间数据库遥感更新研究--以安徽省1:5万土地利用现状数据库为例 总被引：2，自引：0，他引：2
随着我国社会经济快速发展,地理空间数据库的快速动态更新是迫切需要解决的问题.采用遥感TM图像为数据源,基于GIS对数据操作、管理、显示等良好功能以及背景数据知识,通过地学知识发现和综合建立各地类解译标志,直接在空间背景数据库基础上进行多要素修改变更,具有时间省、工作量小、效率和精度高特点,成功地实现了1:5万土地利用现状数据库一级和部分二级地类2000年时相的快速、准确更新.该方法也可应用于其他相应比例尺地理空间数据库的更新. 相似文献
8.
地下储层分布是位置的函数,不同位置处的沉积模式具有差异性。在储层预测时,除了挖掘已有资料所提供的结构和统计信息外,还应该引入待估点位置的信息,以反映沉积储层模式随位置变化的非平稳特征。提出了一种基于沉积模式的多点地质统计学方法,通过距离函数将储层特征与沉积位置相关联,采用整体替换、结构化随机路径以及多重网格策略再现沉积模式。基于现代鄱阳湖沉积所建立的合成非平稳性三角洲前缘沉积地层建模表明,新设计的方法较传统的建模方法更好地反映了三角洲相沉积地层非平稳沉积模式,新设计方法有更好的地质适用性。研究丰富了储层三维建模理论和方法,为实际油藏建模提供了新手段。 相似文献
9.
Snehamoy Chatterjee Roussos Dimitrakopoulos Hussein Mustapha 《Mathematical Geosciences》2012,44(3):343-374
A pattern-based simulation technique using wavelet analysis is proposed for the simulation (wavesim) of categorical and continuous variables. Patterns are extracted by scanning a training image with a template and then storing
them in a pattern database. The dimension reduction of patterns in the pattern database is performed by wavelet decomposition
at certain scale and the approximate sub-band is used for pattern database classification. The pattern database classification
is performed by the k-means clustering algorithm and classes are represented by a class prototype. For the simulation of categorical variables,
the conditional cumulative density function (ccdf) for each class is generated based on the frequency of the individual categories at the central node of the template. During
the simulation process, the similarity of the conditioning data event with the class prototypes is measured using the L
2-norm. When simulating categorical variables, the ccdf of the best matched class is used to draw a pattern from a class. When continuous variables are simulated, a random pattern
is drawn from the best matched class. Several examples of conditional and unconditional simulation with two- and three- dimensional
data sets show that the spatial continuity of geometric features and shapes is well reproduced. A comparative study with the
filtersim algorithm shows that the wavesim performs better than filtersim in all examples. A full-field case study at the Olympic Dam base metals deposit, South Australia, simulates the lithological
rock-type units as categorical variables. Results show that the proportions of various rock-type units in the hard data are
well reproduced when similar to those in the training image; when rock-type proportions between the training image and hard
data differ, the results show a compromise between the two. 相似文献
10.
In this paper, a Bayesian framework is introduced for pattern modeling and multiple point statistics simulation. The method presented here is a generalized clustering-based method where the patterns can live on a hyper-plane of very low dimensionality in each cluster. The provided generalizationallows a remarkable increase in variability of the model and a significant reduction in the number of necessary clusters for pattern modeling which leads to more computational efficiency compared with clustering-based methods. The Bayesian model employed here is a nonlinear model which is composed of a mixture of linear models. Therefore, the model is stronger than linear models for data modeling and computationally more effective than nonlinear models. Furthermore, the model allows us to extract features from incomplete patterns and to compare patterns in feature space instead of spatial domain. Due to the lower dimensionality of feature space, comparison in feature space results in more computational efficiency as well. Despite most of the previously employed methods, the feature extraction filters employed here are customized for each training image (TI). This causes the features to be more informative and useful. Using a fully Bayesian model, the method does not require extensive parameter setting and tunes its parameters itself in a principled manner. Extensive experiments on different TIs (either continuous or categorical) show that the proposed method is capable of better reproduction of complex geostatistical patterns compared with other clustering-based methods using a very limited number of clusters. 相似文献
11.
Multiple-point statistics (MPS) allows simulations reproducing structures of a conceptual model given by a training image (TI) to be generated within a stochastic framework. In classical implementations, fixed search templates are used to retrieve the patterns from the TI. A multiple grid approach allows the large-scale structures present in the TI to be captured, while keeping the search template small. The technique consists in decomposing the simulation grid into several grid levels: One grid level is composed of each second node of the grid level one rank finer. Then each grid level is successively simulated by using the corresponding rescaled search template from the coarse level to the fine level (the simulation grid itself). For a conditional simulation, a basic method (as in snesim) to honor the hard data consists in assigning the data to the closest nodes of the current grid level before simulating it. In this paper, another method (implemented in impala) that consists in assigning the hard data to the closest nodes of the simulation grid (fine level), and then in spreading them up to the coarse grid by using simulations based on the MPS inferred from the TI is presented in detail. We study the effect of conditioning and show that the first method leads to systematic biases depending on the location of the conditioning data relative to the grid levels, whereas the second method allows for properly dealing with conditional simulations and a multiple grid approach. 相似文献
12.
13.
Multiple-point geostatistics has recently attracted significant attention for characterization of environmental variables. Such methods proceed by searching a large database of patterns obtained from a training image to find a match for a given data-event. The template-matching phase is usually the most time-consuming part of a MPS method. Linear transformations like discrete cosine transform or wavelet transform are capable of representing the image patches with a few nonzero coefficients. This sparsifying capability can be employed to speed up the template-matching problem up to hundreds of times by multiplying only nonzero coefficients. This method is only applicable to rectangular data-events because it is impossible to represent an odd-shaped data-event in a transformation domain. In this paper, the method is applied to speed up the image quilting (IQ) method. The experiments show that the proposed method is capable of accelerating the IQ method tens of times without sensible degradation in simulation results. The method has the potential to be employed for accelerating optimization-based and raster-scan patch-based MPS algorithms. 相似文献
14.
Comparison of 2D debris-flow simulation models with field events 总被引：7，自引：0，他引：7
Three two-dimensional (2D) debris-flow simulation models are applied to two large well-documented debris-flow events which
caused major deposition of solid material on the fan. The models are based on a Voellmy fluid rheology reflecting turbulent-like
and basal frictional stresses, a quadratic rheologic formulation including Bingham, collisional and turbulent stresses, and
a Herschel–Bulkley rheology representing a viscoplastic fluid. The rheologic or friction parameters of the models are either
assumed a priori or adjusted to best match field observations. All three models are capable of reasonably reproducing the
depositional pattern on the alluvial fan after the models have been calibrated using historical data from the torrent. Accurate
representation of the channel and fan topography is especially important to achieve a good replication of the observed deposition
pattern. 相似文献
15.
研究建立用多分量感应测井资料同时快速重建水平层状横向同性介质中横向与纵向电阻率和层界面深度的有效方法。首先,利用电磁场摄动方程、电导率函数与模型参数关系方程以及模式匹配算法得到电磁场并矢Green函数的半解析解,建立多分量感应测井响应的Frèchet导数矩阵的快速算法;在此基础上,借助于规范化处理和奇异值分解技术,给出同时反演水平层状地层中各个地层的纵、横向电阻率以及层界面深度的迭代过程,实现理论合成资料与输入资料的最佳拟合。数值计算证明,该反演算法能够取得较满意的反演效果。 相似文献
16.
针对直接采用FLAC3D编制复杂开挖过程力学仿真程序所遇到的困难,开发了FLAC3D力学仿真程序代码生成系统(generating code system,简称GCS)。介绍了如何利用矿用地质软件Surpac,按空间、次序、结构功能及工程地质体属性对复杂开挖过程进行剖分,形成可编程的组件;着重解决了模型单元质心定位、单元捕捉、重组和应用程序变量到FLAC3D变量、函数、语句、数据结构之间映射等问题;使用VC++开发并给出了一个特定回采开挖过程的FLAC3D力学仿真代码生成系统实例,该应用程序以模型单元数据库为数据源,通过一系列与用户交互的页面,由用户对回采开挖过程所需步骤和参数进行选择和确认,并将这些步骤和参数传递给仿真代码生成系统,由系统自动完成FLAC3D力学仿真代码的生成。FLAC3D力学仿真程序代码生成系统架起了地质三维几何造型软件与三维计算软件之间的桥梁,可大大提高编制FLAC3D三维力学仿真代码的效率,降低程序编制的出错率,有利于应用FLAC3D软件更为深广地解决复杂岩土开挖过程中的力学问题。 相似文献
17.
Andreas S. Stordal Randi Valestrand Hans Arnfinn Karlsen Geir N?vdal Hans Julius Skaug 《Computational Geosciences》2012,16(2):467-482
Over the last years, the ensemble Kalman filter (EnKF) has become a very popular tool for history matching petroleum reservoirs.
EnKF is an alternative to more traditional history matching techniques as it is computationally fast and easy to implement.
Instead of seeking one best model estimate, EnKF is a Monte Carlo method that represents the solution with an ensemble of
state vectors. Lately, several ensemble-based methods have been proposed to improve upon the solution produced by EnKF. In
this paper, we compare EnKF with one of the most recently proposed methods, the adaptive Gaussian mixture filter (AGM), on
a 2D synthetic reservoir and the Punq-S3 test case. AGM was introduced to loosen up the requirement of a Gaussian prior distribution
as implicitly formulated in EnKF. By combining ideas from particle filters with EnKF, AGM extends the low-rank kernel particle
Kalman filter. The simulation study shows that while both methods match the historical data well, AGM is better at preserving
the geostatistics of the prior distribution. Further, AGM also produces estimated fields that have a higher empirical correlation
with the reference field than the corresponding fields obtained with EnKF. 相似文献
18.
19.
TANG Ligen ZHU Weiyao ZHU Huayin SUN Chunhui YANG Fenglai WANG Yan Li Xiaorui Li Haiming CHU Guangzhen WANG Jieming KONG Debin YUE Ming LIU Yuwei HUANG Kun 《《地质学报》英文版》2021,95(2):630-637
To tackle the problem that wells that are deployed in a specific pattern based on the requirements of gas reservoir development are not suitable for gas storage,we have conducted concentrically circular injection and production simulation experiments for gas storage,discovered the existence of a threshold radius,denoted by Rt, and derived the expression for Rt.Based on the analysis and discussion results,we propose a strategy for deploying gas storage wells in specific patterns.The expression for Rt shows that it is affected by factors such as the gas storage gas production/injection time,the upper pressure limit,the lower pressure limit,the bottomhole flow pressure at the ends of injection and production,the and permeability. The analysis and discussion results show that the Rt of a gas storage facility is much smaller than the Rt for gas reservoir development.In the gas storage facilities in China,the Rt for gas production is less than the Rt for the gas injection, and Rt increases with the difference in the operating pressure and with permeability K.Based on the characteristics of Rt,we propose three suggestions for gas storage well pattern deployment:(1)calculate Rt according to the designed functions of the gas storage facility and deploy the well pattern according to Rt;(2) deploy sparser,large-wellbore patterns in high-permeability areas and denser,small-wellbore patterns in high-permeability areas;and (3)achieve the gas injection well pattern by new drilling,and the gas production well pattern through a combination of the gas injection well pattern and old wells.By assessing a gas storage facility with a perfect well pattern after a number of adjustments,we found that the Rt of the 12 wells calculated in this paper is basically close to the corresponding actual radius,which validates our method.The results of this study provide a methodological basis for well pattern deployment in new gas storage construction. 相似文献