| 地震波在孔隙介质中低频衰减现象的粘弹性特征分析及近似（英文） |
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| 引用本文： | 凌云,韩立国,张益明.地震波在孔隙介质中低频衰减现象的粘弹性特征分析及近似（英文）[J].应用地球物理,2014,11(4):355-363. |
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| 作者姓名： | 凌云 韩立国 张益明 |
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| 作者单位： | 吉林大学地球探测科学与技术学院;中海石油研究中心; |
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| 基金项目： | sponsored by the National Science and Technology Major Project(Grant No.2011ZX05025-001-07) |
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| 摘 要： | 由于介观尺度的孔隙流体流动,弹性波传播过孔隙岩层时在地震频段表现出较强的频散和衰减。Johnson理论给出了在任意孔隙形状的条件下,部分气水饱和孔隙介质的理论相速度和品质因子的解析解。本文在Johnson模型的基础上,通过对Q值曲线的低频和高频近似,推导了Q值曲线的近似公式,以及基于孔隙介质基本地球物理参数和孔隙斑块几何形态参数T和比表面积S/V的最大衰减Qmin近似公式。通过与理论值的对比,对Qmin近似公式存在的线性误差进行改正,进一步提高了精度。复杂的斑块形态对最大衰减Qmin和过渡频率ftr的都产生一定影响,且对ftr影响更大。因为数值模拟直接求解介观尺度的Biot孔隙介质方程需要极大的计算量,我们使用Zener模型建立了等效粘弹模型,有效地模拟了地震频带内的衰减和频散现象。
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| 关 键 词： | 介观尺度 Johnson模型 衰减 速度频散 Zener模型 |
Viscoelastic characteristics of low-frequency seismic wave attenuation in porous media |
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| Yun?Ling,Li-Guo?HanEmail author,Yi-Ming?Zhang.Viscoelastic characteristics of low-frequency seismic wave attenuation in porous media[J].Applied Geophysics,2014,11(4):355-363. |
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| Authors: | Yun?Ling Email author" target="_blank">Li-Guo?HanEmail author Yi-Ming?Zhang |
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| Institution: | Ling Yun, Han Li-Guo, and Zhang Yi-Ming |
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| Abstract: | Mesoscopic fluid flow is the major cause of wave attenuation and velocity dispersion at seismic frequencies in porous rocks. The Johnson model provides solutions for the frequency-dependent quality factor and phase velocity in partially saturated porous media with pore patches of arbitrary shapes. We use the Johnson model to derive approximations for the quality factor Q at the high and low frequency limit, and obtain the approximate equation for Qmin based on geophysical and geometric parameters. A more accurate equation for Qmin is obtained after correcting for the linear errors between the exact and approximate Q values. The complexity of the pore patch shape affects the maximum attenuation of Qmin and the transition frequency ftr; furthermore, the effect on ftr is stronger than that on Qmin. Numerical solutions to Biot’s equation are computationally intensive; thus, we build an equivalent viscoelastic model on the basis of the Zener model, which well approximates the wave attenuation and dispersion in porous rocks in the seismic band. |
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| Keywords: | Mesoscopic scale johnson model attenuation velocity dispersion zener model |
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