Digital rock physics: numerical prediction of pressure-dependent ultrasonic velocities using micro-CT imaging
Digital rock physics: numerical prediction of pressure-dependent ultrasonic velocities using micro-CT imaging
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DOI：
10.1111/j.1365-246x.2012.05437.x
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发表时间：
2012-06-01
影响因子：
2.8
通讯作者：
Saenger, Erik H.
中科院分区：
文献类型：
--
作者：
Madonna, Claudio;Almqvist, Bjarne S. G.;Saenger, Erik H.
数字岩石物理学将现代微观成像与先进的数值模拟相结合，以分析岩石的物理性质。基于微结构图像的弹性波传播模型被用来估计岩石的有效弹性性质。这篇文章的目的是描述和理解实验室实验如何与使用贝里亚砂岩的数字岩石物理结果进行比较。我们在实验上测量了压力相关的超声速度和孔径分布。数值模拟得到的有效弹性性质是基于微计算机层析成像(Micro-CT)图像的，这些图像系统地比实验室测量的更坚硬。由于断层图像不能分辨样品的小规模气孔和裂缝网络，我们假设数值过高可归因于图像中缺失的最小气孔和颗粒对颗粒的接触。为了协调数值和实验数据之间的差异，我们建议使用晶界重建算法。这允许在虚拟岩石模型中实现和近似迄今未解析的特征。因此，我们可以利用显微CT图像来预测随压力变化的有效速度。
Digital rock physics combines modern microscopic imaging with advanced numerical simulations to analyse the physical properties of rocks. Elastic-wave propagation modelling based on the microstructure images is used to estimate the effective elastic properties of the rock. The goal of this paper is to describe and understand how laboratory experiments compare with digital rock physics results using Berea sandstone. We experimentally measure pressure-dependent ultrasonic velocities and the pore size distribution. The effective elastic properties resulting from numerical simulations are based on microcomputed tomography (micro-CT) images, which are systematically stiffer than the laboratory measures. Because the tomographic images do not resolve the small-scale pore and crack network of the sample, we hypothesize that the numerical overprediction is attributable to the smallest pores and grain-to-grain contacts that are missing in the images. To reconcile the difference between numerical and experimental data, we suggest to use a grain boundary reconstruction algorithm. This allows to implement and approximate so far unresolved features in the virtual rock model. As a result, we can predict pressure-dependent effective velocity using micro-CT images.