利用折射波的海底节点地震三分量检波器重定向方法

在海底节点(Ocean Bottom Nodes, OBN)地震中，因为水下检波器实际姿态的任意性，三分量检波器的重定向成为OBN勘探需解决的首要问题。为此，提出一种根据折射波偏振特性进行OBN三分量检波器重定向的方法。首先，引入三个欧拉角描述坐标系的旋转，给出检波点两侧炮点产生折射波偏振矢量的三种特性，并根据该三种特性建立误差函数以描述检波器姿态与设计姿态的偏差；然后，利用不同欧拉角对原始地震记录进行旋转，每次旋转后求取检波点两侧炮点产生折射波的偏振矢量，并计算相应的误差函数，误差函数最小的欧拉角即为姿态校正角；最后，利用求取的校正角对原始地震记录进行校正，即可实现检波器重新定向，从而将实际采集信号校正到检波器沿设计方位放置时应有的地震记录。模型试验和实际数据处理结果表明，该方法易于实现且计算精度高，可用于未安装罗经姿态传感器的OBN地震数据校正。

Three-component geophone reorientation method based on refracted waves for ocean bottom nodes seismic survey

For ocean bottom nodes (OBN) seismic exploration,since the orientation of a geophone at the sea bottom is unknown,three-component geophone reorientation is a primary problem to be solved in OBN seismic exploration. This paper proposes a three-component geophone reorientation method for OBN exploration based on the polarization characteristics of the refraction waves produced by the shots on both sides of the detection point. First,we introduce three Euler angles to describe the rotation of the coordinate system and establish an error function based on the characteristics of polarization vectors to describe the deviation between the actual orientation and the design orientation of the geophone. Then we use different Euler angles to rotate the original seismic data. After each rotation,we can achieve the polarization vectors of the refracted waves produced by the shots on both sides of the detection point and calculate the corresponding error function. The Euler angle that minimizes the error function is the correction angle. The obtained correction angle can be used to correct the original seismic record and realize the reorientation of the geophone. Consequently, the actual signals can be corrected to be the seismic records when the geophone is placed in line with the design orientation. We apply the proposed method to synthetic data and field data,and the results show that the method is easy to implement with high calculation accuracy. This method can be used in the correction of OBN seismic data in the case of without a compass sensor for orientation.