Poroelastic coupling between fractures and the surrounding rock is important to numerous applications in geosciences. We measure the in-situ fluid pressure and local strain response of a fractured carbonate sample to hydrostatic pressure oscillations. A linear poroelastic model that represents the rock sample is parameterized using X-ray imaging and ultrasonic wave transmission measurements. The numerical solution, based on Biot's quasistatic equations, is consistent with the measured frequency dependent dispersion of the apparent bulk modulus of the background matrix and the in-situ pore pressure response, which is caused by fluid pressure diffusion from the compliant fractures into the stiffer matrix. The observed fluid pressure diffusion is causally related to the numerically quantified intrinsic attenuation at seismic frequencies, which is a major contributor to the dissipation of seismic waves. Our analysis supports the use of a simple approximation of fractures as compliant and planar inclusions in numerical simulations based on linear poroelasticity.

中文翻译：

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裂隙岩石对静水压力振荡的多孔弹性响应


裂缝与周围岩石之间的多孔弹性耦合对于地球科学中的许多应用都很重要。我们测量了裂隙碳酸盐样品的原位流体压力和局部应变响应对静水压力振荡的响应。代表岩石样品的线性多孔弹性模型使用 X 射线成像和超声波透射测量进行参数化。基于 Biot 准静态方程的数值解与测得的背景基体表观体积模量的频率依赖性色散和原位孔隙压力响应一致，这是由流体压力从柔顺性裂缝扩散到较硬的基体引起的。观测到的流体压力扩散与地震频率下数值量化的固有衰减有因果关系，这是地震波消散的主要因素。我们的分析支持在基于线性多孔弹性的数值模拟中使用裂缝的简单近似作为柔和平面夹杂物。