薄层复合波振幅与厚度函数关系的改进

薄层厚度的定量预测方法一直是地球物理学家研究的热点问题之一。预测主要是通过建立薄层厚度与地震反射波振幅、频谱、地震属性之间的关系,进而直接或间接地预测薄层厚度。这种函数关系依赖于选取的地震子波的特性。已有的研究成果中选用的地震子波基本上是实际地震子波的近似,由于子波的误差不可避免地会影响函数关系的精度。选取更为接近实际情况的黏弹性波解作为地震子波,建立了薄层顶底反射的复合波振幅与厚度的一阶近似关系,与Widess的近似关系相比具有更高的精度。

Improvement of function between thin-bed composite amplitude and its thickness

The quantitative prediction of thin-bed thickness is the one of important problems of the geophysicist’s research.These methods is often implemented through establishing the relationships between thin-bed thickness and seismic dominant amplitude，frequency or other attributes，and then used to directly or indirectly predict thin-bed thickness.These relationships are always dependent on the characteristics of selected seismic wavelet，which is an approximation of realistic wavelet.However，the calculation of selected wavelets is subject to the influence of seismic data quality and its accuracy is not sufficient.A more realistic wavelet was presented in this paper using the solution of viscoelastic wave equations.The first order approximation formula was established to describe the relationship between the thin-bed thickness and the amplitude of compound seismic waves reflected from top and bottom of thin-bed.Compared with the Widess’s method，the proposed method has a higher precision.