基于直达波偏振分析的三分量检波器定向方法

A three-component geophone orientation method based on direct P-wave polarization

本文提出一种基于三分量地震记录直达波偏振分析的三分量检波器定向方法。该方法首先利用三分量地震记录的直达波振幅构造协方差矩阵,然后通过求解该协方差矩阵的主特征向量得到直达波的偏振方向,再根据炮点和接收点的位置计算直达波的传播方向,在此基础上,利用直达波的偏振方向和传播方向的差异最终确定三分量检波器与设计方向的水平和垂直偏角。利用估算的三分量检波器的水平和垂直偏角,通过三分量旋转技术实现三分量地震记录的重定向,进而消除由于三分量检波器放置方向的误差对波场带来的影响。模型和实际数据试算结果表明,该方法具有很高的计算精度和很好的应用效果。

For ocean bottom cable(OBC)surveys,it is difficult to precisely control the orientation of ocean-bottom seismometers in the marine environment.In this case,different wave energy will be projected to all the three components and will cause adverse influence on the subsequent processing imaging and inversion.This paper proposes a three-component geophone orientation estimation method by polarization analysis of three-component seismic records.Firstly the particle movement direction of the direct P-wave can be estimated with the principal eigenvector of the covariance matrix formed by the amplitudes of the direct P-wave of three-component seismic records.Then the propagation direction of the direct P-wave can be calculated with the source-receiver geometry.Finally the horizontal and vertical deviation angles of threecomponent geophones can be obtained by the relation between the particle movement direction and the propagation direction of the direct P-waves in the assumption of isotropic and homogeneous medium.Tests on synthetic and real data show that the proposed method can accurately estimate orientation of three component geophones.