Digital rock physics applied to squirt flow
Digital rock physics applied to squirt flow
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DOI：
10.1190/geo2020-0731.1
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发表时间：
2021-04
期刊：
影响因子：
3.3
通讯作者：
Simón Lissa;M. Ruf;H. Steeb;B. Quintal
中科院分区：
文献类型：
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作者：
Simón Lissa;M. Ruf;H. Steeb;B. Quintal
我们已经开发了一个工作流程，用于计算地震波模量的分散和衰减，由于喷流的数值模型来自于微X射线计算机断层扫描图像的开裂（通过热处理）卡拉拉大理石样品。为了生成数值模型，对图像进行处理、分割和网格化。采用有限元法求解线性化的准静态Navier-Stokes方程，该方程描述了裂纹内可压缩粘性流体的层流流动，并与固相的准静态Lamé-Navier方程耦合。我们计算有效的P-和S-波模量在三个笛卡尔方向的模型在干燥的条件下（饱和空气）和一个较小的模型完全饱和甘油和排水或不排水的边界条件。对于甘油饱和的模型，结果表明显着的和频率依赖的P-和S-波衰减和相应的色散所造成的喷流。喷射流响应于由施加的变形在裂缝中引起的流体压力梯度而发生。我们的数字岩石物理工作流程可用于使用岩石样本的图像解释衰减的实验室测量结果。
We have developed a workflow for computing the seismic-wave moduli dispersion and attenuation due to squirt flow in a numerical model derived from a micro X-ray computed tomography image of cracked (through thermal treatment) Carrara marble sample. To generate the numerical model, the image is processed, segmented, and meshed. The finite-element method is adopted to solve the linearized, quasistatic Navier-Stokes equations describing laminar flow of a compressible viscous fluid inside the cracks coupled with the quasistatic Lamé-Navier equations for the solid phase. We compute the effective P- and S-wave moduli in the three Cartesian directions for a model in dry conditions (saturated with air) and for a smaller model fully saturated with glycerin and having either drained or undrained boundary conditions. For the model saturated with glycerin, the results indicate significant and frequency-dependent P- and S-wave attenuation and the corresponding dispersion caused by squirt flow. Squirt flow occurs in response to fluid pressure gradients induced in the cracks by the imposed deformations. Our digital rock-physics workflow can be used to interpret laboratory measurements of attenuation using images of the rock sample.