The migration-based microseismic event location methods using waveform stacking algorithms are widely used for hydro-fracturing monitoring. These methods have the advantage of not requiring the accurate first arrival time around a detected event, which is more suitable for noisy data than classical travel time-based methods. However, accuracy of these methods can be affected under the condition of relatively low signal-to-noise ratio (SNR). Therefore, in order to enhance the location accuracy of microseismic events in a borehole system, we have proposed a migration-based location method using improved waveform stacking with polarity correction based on a master-event technique, which optimizes the combination way of P- and S-wave waveform stacking. This method can enhance the convergence of the objective function and the location accuracy for microseismic events as compared to the conventional waveform stacking. The proposed method has been successfully tested by using synthetic data example and field data recorded from one downhole monitoring well. Our study clearly indicates that the presented method is more viable and stable under low SNR.

使用波形叠加算法的基于偏移的微地震事件定位方法被广泛用于水力压裂监测。这些方法的优点是不需要围绕检测到的事件的准确的首次到达时间，这比基于传统旅行时间的方法更适合于嘈杂的数据。但是，这些方法的准确性可能会在信噪比（SNR）相对较低的情况下受到影响。因此，为了提高井筒系统中微震事件的定位精度，我们提出了一种基于偏移的定位方法，该方法利用基于主事件技术的经过改进的叠加有极性校正的波形叠加技术，优化了P-和小号波波形叠加。与传统的波形叠加相比，该方法可以增强目标函数的收敛性和微震事件的定位精度。通过使用合成数据示例和从一口井下监测井记录的现场数据，已成功测试了该方法。我们的研究清楚表明，该方法在低信噪比下更可行，更稳定。