Computation of dynamic seismic responses to viscous fluid of digitized three-dimensional Berea sandstones with a coupled finite-difference method.
Computation of dynamic seismic responses to viscous fluid of digitized three-dimensional Berea sandstones with a coupled finite-difference method.
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DOI：
10.1121/1.4733545
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发表时间：
2012-08
期刊：
影响因子：
--
通讯作者：
Yang Zhang;M. Toksöz
中科院分区：
文献类型：
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作者：
Yang Zhang;M. Toksöz
利用三维数字化Berea砂岩的微层析图像，数值研究了饱和多孔岩石的地震响应。应力-应变计算用于计算岩石样品的速度和衰减，其尺寸远小于感兴趣的地震波长。为了补偿在成像过程中丢失的小裂纹对总速度和衰减的贡献，开发了一种混合方法来恢复裂纹分布，其中微分有效介质理论，Kuster-Toksöz模型和修改的喷流模型被用于两步Monte Carlo反演。在反演中，使用的P-和S-波的速度测量的干和水饱和的情况下，和测量的衰减的P-波为不同的流体。通过使用这种混合方法，饱和多孔岩石的速度和衰减的预测准确时，与实验室数据相比。混合方法是一种实用的方法，数值模拟饱和多孔岩石的地震属性，直到非常高的分辨率数字数据。在成像过程中丢失的裂缝对于准确预测饱和多孔岩石的速度和衰减是至关重要的。
The seismic response of saturated porous rocks is studied numerically using microtomographic images of three-dimensional digitized Berea sandstones. A stress-strain calculation is employed to compute the velocities and attenuations of rock samples whose sizes are much smaller than the seismic wavelength of interest. To compensate for the contributions of small cracks lost in the imaging process to the total velocity and attenuation, a hybrid method is developed to recover the crack distribution, in which the differential effective medium theory, the Kuster-Toksöz model, and a modified squirt-flow model are utilized in a two-step Monte Carlo inversion. In the inversion, the velocities of P- and S-waves measured for the dry and water-saturated cases, and the measured attenuation of P-waves for different fluids are used. By using such a hybrid method, both the velocities of saturated porous rocks and the attenuations are predicted accurately when compared to laboratory data. The hybrid method is a practical way to model numerically the seismic properties of saturated porous rocks until very high resolution digital data are available. Cracks lost in the imaging process are critical for accurately predicting velocities and attenuations of saturated porous rocks.