基于Tene-cor自动聚焦成像算子的弹性波微地震逆时定位

微地震震源定位是微地震研究中的关键技术, 微地震震源位置可以通过微地震信号的逆时反传来确定。在弹性介质逆时定位过程中, 微地震信号中的P波、S波会耦合在一起, 在震源聚焦结果中产生假象, 影响震源方位的拾取。提出了基于Tene-cor聚焦成像算子的弹性波微地震逆时定位算法, 首先, 通过纵横波解耦的弹性波方程得到P波和S波的逆时波场, 然后, 施加Tene-cor成像算子对解耦的逆时波场记录进行互相关成像得到震源位置。分别利用合成数据和野外实际数据测试了该算法的定位效果。数值算例表明, 该定位算法除了能够压制成像结果中因波场耦合导致的串扰噪声外, 还可以聚焦因干涉成像产生的辐射状假象, 在不同检波器采集条件、频带缺失和速度模型不精确的条件下, 该算法相较于传统定位成像算法能够有效提高震源定位分辨率。

Source location is a key technique in microseismic research, and microseismic sources can be located by reverse time propagation of microseismic signals.In the process of reverse time location in elastic media, coupled P-waves and S-waves in microseismic signals will produce artifacts in source focusing results, which have a negative impact on picking source locations.We propose an elastic-wave reverse-time microseismic location algorithm based on the Tene-cor focusing imaging operator.Elastic wave equations with decoupled P- and S-waves are used to obtain the reverse-time wave fields of P- and S-waves, which are then imaged through cross correlation using the Tene-cor imaging operator to obtain source locations.The algorithm is tested using synthetic data and field data.Numerical examples show that the location algorithm proposed in this paper can focus the radial artifacts generated by interference imaging in addition to suppressing the crosstalk noises caused by wavefield coupling in the imaging results.Compared with traditional algorithms, our method can effectively improve the resolution of source location in the context of different receiver conditions, missing frequency bands, and inaccurate velocity models.