零偏VSP衰减特性正反演模型试验

Forward Modeling Experiment on Attenuation Characteristics of Zero-offset VSP

当地震波在地层中传播时,能量的衰减是介质粘弹性性质的反应。这种介质所固有的衰减特性一般用品质因子Q来描述。该文研究的是零偏VSP衰减地震波长的正演模拟,在正演算法上采用了层状介质的波长递推公式,在基于"Ganley模型"的理论下模拟出了零偏VSP合成记录。为了验证正演模拟的正确性,用质心频率偏移法(Centroid Frequency Shift,简称CFS)对理论模型的Q值进行提取。模型结果表明了该文正演方法的正确性,也证明了CFS方法的实用性。

Energy attenuation is the reflection of non-elastic property of medium when seismic wave prop- agates in the straum, which attenuation characteristic of medium is usually represented by quality factor Q. This paper studies the forward modeling of zero-offset VSP attenuation seismic wave length, and the reeursion formula of wave length in layered medium is adopted in the forward simulation arithmetic. Based on the Ganley model, the zero-offset synthesized VSP data is simulated. In order to verify the cor- rectness of forward modeling, the centroid frequency shift method （CFS for short） is used to inverse the Q values on the forward zero-offset VSP geological model. The model results show that the correctness of forward modeling method, which also CFS method＇s practicality.