Prediction of dispersion and attenuation on elastic wave velocities in partially saturated rock based on the fluid distribution obtained from three-dimensional (3D) micro-CT images

Frontiers in Earth Science

Earth Science

Chao Sun¹  Jérôme Fortin²  Genyang Tang³  Shangxu Wang³ 

[1] College of Resources and Geoscience, China University of Mining and Technology, Xuzhou, China;Laboratoire de Géologie, Ecole Normale Supérieure/CNRS, UMR8538, PSL Research University, Paris, France;State Key Laboratory of Petroleum Resources and Prospecting, Key Laboratory of Geophysical Prospecting, China National Petroleum Corporation, China University of Petroleum, Beijing, China;

关键词: 3D CT image;    dispersion;    attenuation;    mesoscopic-flow;    numerical modeling;   

DOI  :  10.3389/feart.2023.1267522

 received in 2023-07-26, accepted in 2023-08-14,  发布年份 2023

来源: Frontiers

【 摘 要 】

Elastic wave attenuation in partially saturated porous rock is primarily due to wave-induced fluid flow, which arises from the contrast in compressibility between air and water and is influenced by the water distribution within the rock. We propose a method for constructing a numerical model that predicts mesoscopic dispersion and attenuation. Initially, we use fluid distribution data sourced from 3D X-ray Computed Tomography images to construct the numerical model, utilizing Biot’s poroelastic equations as the governing equations. Subsequently, we implement the finite element method to derive solutions for the numerical model. Our focus is centered on two key challenges: 1) reducing memory cost, and 2) efficiently handling element intersection during the meshing process. The solutions illustrate the evolution of fluid pressure distribution and the frequency-dependent advancement of the elastic moduli, coupled with their corresponding attenuation. Ultimately, we compare these numerical predictions with previously published experimental data from a study on partially saturated Indiana limestone. The considerable agreement between our numerical results and the experimental data confirms the validity of our method, which crucially incorporates the actual fluid distribution (captured from 3D CT images) as a vital input.

【 授权许可】

Unknown   
Copyright © 2023 Sun, Fortin, Tang and Wang.