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Study on Multi-scaling Laws of Rock Structures Affecting Hydraulic Properties

岩石结构影响水力特性的多尺度规律研究

基本信息

批准号：
14350535
负责人：
KOIKE Katsuaki
金额：
$ 4.22万
依托单位：
Kumamoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14350535/
关键词：
Rock Hydraulic Property Pore Fracture Scaling Law Geostatistics Spatial Estimation Variogram

项目摘要

Spatial estimation of geologic attributes requires extension of their properties, which are obtained from borehole cores and sampling at restricted points, to field scale. Therefore, scaling law, which relates data distributions at different scales, is indispensable to obtain detailed spatial model over wide area. Although fractal has been generally used as such a scaling law, it doe not consider spatial correlation structures specific to geologic attributes. We clarified that simulated annealing (SA) method, which adjusts the semivariogram of data selected randomly from the histogram to the semivariogram model defined, was the most suitable to spatial estimations at different scales, and proposed a new combination of scaling laws for the data and semivariogram.The SA was used for a pore distribution modeling in geologic media using bubble concrete material as a simulated porous rock. Pore distributions at several scales, 1×1 cm^2, 5×5 cm^2, 10×10 cm^2, 50×50 cm^2, 1×1 m^2, and 5×5 m^2, were modeled from the sectional pore data of cylindrical samples with 5 cm in diameter and 10 cm in height. The two scaling laws of pore radius on the semivariogram and histogram were used. Although the porosity was fixed, pores were connected largely with the increase of scale. This simulation result is also used to examine the effect of connectivity on hydraulic conductivity by comparing the hydraulic test results, which contributes to interpret the scale effect of hydraulic conductivity and estimate it at regional scale. The proposed method was also applied to the Berea sandstone samples, one of the well-studied porous sandstone over the world, and clarified a similar trend found in the simulation for the bubble concrete materials.

地质属性的空间估计需要将从钻孔岩心和限制点采样获得的属性扩展到野外尺度。因此，尺度律关系到数据在不同尺度上的分布，对于获得大范围内的详细空间模型是必不可少的。虽然分形通常被用作这样一种标度律，但它没有考虑特定于地质属性的空间相关性结构。阐明了将从直方图中随机选取的数据的半方差函数调整为定义的半方差函数模型的模拟退火法最适合于不同尺度下的空间估计，并提出了一种新的尺度律与半方差函数的组合，将模拟退火法用于模拟多孔岩石的地质介质中的孔隙分布。根据直径5 cm、高10 cm的圆柱状样品的截面孔隙数据，模拟了1×1 cm~2、5×5 cm~2、10×10 cm~2、50×50 cm~2、1×1 m~2和5×5 m~2几个尺度上的孔隙分布。采用半方差函数和直方图上的两个孔半径标度律。虽然孔隙率是固定的，但随着鳞片尺寸的增加，孔洞大量连通。通过与水力试验结果的比较，验证了连通性对渗透系数的影响，有助于解释渗透系数的尺度效应，并在区域尺度上进行估算。所提出的方法也被应用于贝里亚砂岩样品，这是世界上研究得很好的多孔砂岩之一，并阐明了在泡沫混凝土材料的模拟中发现的类似趋势。