Laboratory measurements of guided‐wave propagation within a fluid‐saturated fracture
Laboratory measurements of guided‐wave propagation within a fluid‐saturated fracture
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流体饱和裂缝内导波传播的实验室测量
DOI：
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发表时间：
2016
期刊：
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通讯作者：
V. Korneev
中科院分区：
文献类型：
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作者：
S. Nakagawa;S. Nakashima;V. Korneev
固体之间流体饱和的平坦通道，如裂缝，支持导波，有时被称为克劳克利斯波。在低频时，克劳克利斯波速度极低，衰减大，频散性强。由于kraklis波主要在裂缝形成的流体通道内传播，因此可以用于现场的地质裂缝表征。利用由一对扁平细长板和介质流体层组成的模拟裂缝（三层模型），我们对克劳克利斯波的速度和衰减进行了实验室测量。与以前使用超声波的实验不同，这些实验使用的频率远低于1千赫，导致极低的速度和波的大衰减。通过改变物理裂缝模型的流体密封刚度来改变裂缝的力学顺应性，并且还将支撑剂（裂缝填充高渗透砂）引入裂缝中以研究其对波传播的影响。利用孔弹性线滑界面模型推导了三层模型的理论频率方程，并将其解与实验结果进行了比较。
A fluid‐saturated flat channel between solids, such as a fracture, is known to support guided waves—sometimes called Krauklis waves. At low frequencies, Krauklis waves can have very low velocity and large attenuation and are very dispersive. Because they propagate primarily within the fluid channel formed by a fracture, Krauklis waves can potentially be used for geological fracture characterization in the field. Using an analogue fracture consisting of a pair of flat slender plates with a mediating fluid layer—a trilayer model—we conducted laboratory measurements of the velocity and attenuation of Krauklis waves. Unlike previous experiments using ultrasonic waves, these experiments used frequencies well below 1 kHz, resulting in extremely low velocity and large attenuation of the waves. The mechanical compliance of the fracture was varied by modifying the stiffness of the fluid seal of the physical fracture model, and proppant (fracture‐filling high‐permeability sand) was also introduced into the fracture to examine its impact on wave propagation. A theoretical frequency equation for the trilayer model was derived using the poroelastic linear‐slip interface model, and its solutions were compared to the experimental results.