Seismic wave attenuation and dispersion resulting from wave-induced flow in porous rocks - A review
Seismic wave attenuation and dispersion resulting from wave-induced flow in porous rocks - A review
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DOI：
10.1190/1.3463417
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发表时间：
2010-09-01
期刊：
影响因子：
3.3
通讯作者：
Lebedev, Maxim
中科院分区：
文献类型：
--
作者：
Mueller, Tobias M.;Gurevich, Boris;Lebedev, Maxim
非均匀多孔介质中弹性波衰减的一个主要原因是不同尺度的非均匀性之间的孔隙流体的波动。据信，对于低于1 kHz的频率，最重要的原因是介观不均匀性之间的波诱导流动，介观不均匀性与典型的单个孔径相比较大，但与波长相比较小。在一些天然多孔材料中的各种实验室实验提供了厘米尺度介观不均匀性存在的证据。流体饱和岩石中地震衰减的实验室和现场测量提供了波致流动作用的迹象。波致流动的特征包括P波衰减的频率和饱和度依赖性及其相关的速度色散、频率依赖性剪切波分裂和衰减各向异性。在过去的四十年中，已经开发了许多波诱导流的衰减和速度弥散模型，其严格性和复杂性程度各不相同。这些模型可以根据其基本理论框架大致分为三类。第一组模型是基于毕奥的孔隙弹性理论。第二组是基于弹性动力学理论，其中局部流体流动通过一个额外的流体动力学方程。另一组模型是用粘弹性理论推导出来的。尽管所有模型都预测了弛豫过程典型的衰减和速度弥散，但存在差异，这些差异可能与无序类型（周期性、随机、空间维度）以及局部流动的合并方式有关。这些差异表现在衰减的不同渐近标度律和特征频率的不同表达式中。近年来，一些波浪诱导流体流动的理论模型已经得到了数值验证，使用有限差分，有限元和反射率算法应用于毕奥的孔隙弹性方程。将理论模型应用于真实的地震数据需要进一步研究，使用不同岩石的衰减和频散的宽带实验室和现场测量，以及开发更可靠的方法来估计来自现场数据的耗散属性。
One major cause of elastic wave attenuation in heterogeneous porous media is wave-induced flow of the pore fluid between heterogeneities of various scales. It is believed that for frequencies below 1 kHz, the most important cause is the wave-induced flow between mesoscopic inhomogeneities, which are large compared with the typical individual pore size but small compared to the wavelength. Various laboratory experiments in some natural porous materials provide evidence for the presence of centimeter-scale mesoscopic heterogeneities. Laboratory and field measurements of seismic attenuation in fluid-saturated rocks provide indications of the role of the wave-induced flow. Signatures of wave-induced flow include the frequency and saturation dependence of P-wave attenuation and its associated velocity dispersion, frequency-dependent shear-wave splitting, and attenuation anisotropy. During the last four decades, numerous models for attenuation and velocity dispersion from wave-induced flow have been developed with varying degrees of rigor and complexity. These models can be categorized roughly into three groups according to their underlying theoretical framework. The first group of models is based on Biot's theory of poroelasticity. The second group is based on elastodynamic theory where local fluid flow is incorporated through an additional hydrodynamic equation. Another group of models is derived using the theory of viscoelasticity. Though all models predict attenuation and velocity dispersion typical for a relaxation process, there exist differences that can be related to the type of disorder (periodic, random, space dimension) and to the way the local flow is incorporated. The differences manifest themselves in different asymptotic scaling laws for attenuation and in different expressions for characteristic frequencies. In recent years, some theoretical models of wave-induced fluid flow have been validated numerically, using finite-difference, finite-element, and reflectivity algorithms applied to Biot's equations of poroelasticity. Application of theoretical models to real seismic data requires further studies using broadband laboratory and field measurements of attenuation and dispersion for different rocks as well as development of more robust methods for estimating dissipation attributes from field data.