【摘要】 从七北101井零偏VSP记录中的一组强波出发,通过对零偏与非零偏VSP原始波场中直达纵波和下行转换波第一波至时间的分析,证明其一为纵波震源所激发的纵波在地表某个强阻抗差界面上产生的转换横波。由于这种波具有纯横波的运动学特点,我们可以用于计算横波的速度。利用直达波初至进行三分量矢量定位,在横向垂直分量上得到了信噪比较高的直达横波,选取振幅较强的同相轴提取初至时间,进一步求取了横波速度及泊松比。更多还原

【Abstract】 The arrival time of the compressional waves and downward converted waves in zero and nonzero-offset VSP wave fields were analyzed based on a group of strong wave in zero VSP logs in Qibei 101. The result showed that one of them was converted S wave, converted from the compressional wave generated from compressional wave source, generated on a strong impedance surface. The S wave velocity is calculated by the converted waves as it is of kinematics feature of pure S wave. The three component vectors were adjusted by the arrival of direct wave, the direct S wave, which were high S/N ratio, were obtained and the arrival time were picked up from strong amplitude events. The velocities of shear waves and poisson ratio were calculated.更多还原