井间地震纵横波分离方法研究及应用

Study on P and S wave separation method in cross-well seismic and its application

以VSP和井间地震勘探为主的井孔地震资料采集需采用三分量地震采集技术,该技术能够记录下信息丰富的地震波场,但是纵波波场和横波波场耦合在一起,成为多分量地震资料处理的重点和难点。通过对井孔地震资料采集观测系统的分析和研究,结合纵波波场和横波波场在不同分量上的关系,可以得到纵波和横波的极性与视速度,以及地震波到达检波器接收排列方向之间的关系。据此在基于Cauchy分布的高分辨率Radon变换的基础上,得到纵波波场和横波波场的分布关系,并在τ(截距时间)-p(视慢度或斜率)域中利用极化滤波方法,实现纵波波场与横波波场的有效分离。通过正演模拟数据试算和实际井间地震资料处理效果分析,认为该方法能够有效地分离纵波波场和横波波场,为后续纵横波的独立成像奠定了基础。

Three-component seismic acquisition technology used in VSP and cross-well seismic can record wealthy seismic wave field. The P and S wave couple together, which becomes the difficulty and emphasis of data processing. Through analyzing borehole seismic acquisition system, combined with polarity relation of P and S wave in different components, we can associate polarity of P and S wave with apparent velocity and direction of seismic wave reaching the geophone array. According to this relation, we obtained the distribution relation of P and S wave in τ-p domain based on the linear Radon transform （LRT）. Considering the convergence of LRT, we designed a polarization filtering method using the high-resolution Radon transform, and then accomplished the separation of P and S wave. The processing of simulated data of theoretical model and practical cross-well model separated P and S wave field successfully, which is useful for independent imaging of P and S wave.