空间相关分析因素对储层建模中克里金估计结果的影响

研究采样数据的空间分布及合理地选择参数是得到符合真实地质情况的克里金估计结果的基础。利用某储层数据来研究空间相关分析的主要影响因素与克里金估计结果的直接关系 ,为正确使用这些参数提供参考。这些因素与参数包括采样点的位置分布特征、变差函数模型的块金效应、变差函数模型的变程、变差函数模型的类型、空间结构的各向异性和空间搜索范围。在分析每种因素影响的同时 ,给出了相应的实际数据估计的结果图。研究结果表明 ,距离估计点较近的采样点对估计结果的影响较大 ;主轴方向的采样点比垂直于主轴方向上的采样点对估计结果的影响大 ;搜索半径通常取 1.3～ 2倍的变程值。同时还认为 ,在大多数情况下应选用球状模型和指数模型 ,除非十分必要时使用高斯模型

Effects of the factors for spatial correlation analysis on Kriging estimation in reservoir modeling

The spatial distribution analysis of the sampled data and the proper selection of parameters are the precondition of realistic Kriging estimation map consistent with the geologic information. The ordinary Kriging algorithm was taken as an example to study the direct relationships between the main factors and estimation map, in order to provide an useful reference for the correct selection of the parameters. These factors or parameters include the distribution characteristics of sampled data, and the nugget effect, range and type of variation model, as well as the anisotropy and searching range of space configuration. When the effect of each factor or parameter is analyzed, the relative estimation maps obtained form the practical data can be presented. The results show that the sampling points near the estimated location have larger weight values for the Kringing estimation, and the sampling points in the direction parallel to the main axis have a larger effect on the estimated value than the vertical direction. The searching radius usually ranges from 1.3 to twice times of the variogram range. The ball and index models should be chosen in common condition, and the Gauss model is used in some necessary conditions.