Abstract

We present a numerical investigation of the fracture connectivity effect on attenuation of seismic waves propagating in fractured porous fluid-saturated media. We design an algorithm for statistical modeling to generate fracture systems with prescribed percolation length. Generated statistical realizations of the fractured systems are then analyzed to evaluate the fracture-cluster length-scale. After that for all statistical realizations we simulated wave propagation observing formation of the wave-induced fluid flows. We show that fracture-to-background fluid flows are secretive to the branch size. Thus, in the case of permeable background, seismic attenuation is affected by the branch length; i.e., attenuation increases with the increase of the branches length. If the permeability of the background material is low, no fracture-to-background wave-induced fluid flows appear, whereas strong fracture-to-fracture fluid flows may take place. However, fracture-to-fracture fluid flows are local and depend only on the parameters of the individual fractures and their intersections. As a result, the effect of the fracture-to-fracture fluid flows on seismic attenuation is relatively low, even smaller than the attenuation due to scattering.

中文翻译：

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裂缝系统不同渗流长度的裂缝性多孔介质中的波传播

摘要

我们提供了一个裂缝连通性对在多孔多孔流体饱和介质中传播的地震波衰减的数值研究。我们设计了一种用于统计建模的算法，以生成具有规定渗流长度的裂缝系统。然后分析裂缝系统的生成统计实现，以评估裂缝群长度尺度。之后，对于所有统计实现，我们都模拟了波传播，观察了由波引起的流体流动的形成。我们表明，从裂缝到背景的流体流动是分支尺寸的秘密。因此，在具有可渗透背景的情况下，地震衰减受到分支长度的影响。即，衰减随着分支长度的增加而增加。如果背景材料的渗透率低，没有出现裂缝到背景波引起的流体流动，而可能发生强烈的裂缝到裂缝的流体流动。然而，裂缝间的流体流动是局部的，并且仅取决于单个裂缝及其相交的参数。结果，裂缝到裂缝的流体流动对地震衰减的影响相对较低，甚至小于由于散射引起的衰减。