地层衰减定量模拟的地震物理模拟方法

Q值是描述地层衰减特征的重要地震物理参数，研究Q值对提高地震资料分辨率，提高地震成像精度具有重要意义.本文从地震物理模拟中模型材料的动力学特征出发，提出了一种地层衰减定量模拟的地震物理模拟方法.通过铝样验证了衍射校正方法的准确性，利用有机玻璃实验分析了不同测量方法求取Q值的测量精度问题，从而优选测量方法；然后基于复合材料的实验数据，建立复合材料配比与各物理参数之间的函数关系，利用该函数关系指导地层衰减定量模拟.结合单层地震物理模型和近地表地震物理模型，研究了模拟地震记录及其频谱特征与野外实际情况之间的相似性，基于建立的函数关系研究分析了地层衰减定量模拟的准确性.实验结果表明，基于地震衰减定量模拟方法构建近地表地震物理模型时，模型中模拟参数不仅与设计参数保持很好的一致性，同时具有很高的准确性，模拟地层的频谱衰减特征与野外地层保持一致.

A method of seismic physical modeling for quantitative simulation of formation attenuation

The Q value is an important seismic physical parameter to describe attenuation characteristics of formation. It is of great significance to improvement of resolution of seismic data and accuracy of seismic imaging. In this paper, a seismic physical modeling method for the quantitative simulation of formation attenuation is proposed based on dynamic characteristics of attenuation materials. Firstly, the accuracy of the diffraction correction method is verified with the aluminum. Secondly the stability and accuracy of different measurements are analyzed through experiments on lucite, so as to select a preferable method for Q estimation. Then, the function between the mass ratio of compound materials and physical parameters is established based on experimental data, which can be used in quantitative simulation of formation attenuation. Combined with a single-layer seismic physical model and a near-surface seismic physical model, the similarities between the field situation and simulated seismic records as well as its spectral characteristics are studied. In addition, the accuracy of quantitative simulation of formation attenuation is analyzed by comparing the differences between the material Q values and the inversion Q values of the physical model. The results show that the simulation parameters of the model are not only consistent with the design ones, but also of high accuracy. Meanwhile, the attenuation characteristics of the simulated formation also show consistency with those of the formation in the field.