Microseismic monitoring is a common means to guide hydraulic fracturing operations and evaluate fracturing effects in shale gas extraction.The signal collected by ground monitoring has weak energy and low signal-to-noise ratio,which makes it difficult to identify microseismic events,and seriously affects the accuracy of positioning.Aiming at the ground microseismic monitoring data with low signal-to-noise ratio,a new noise cancellation method is proposed by combining synchronoussqueezing S-transform,spectral decomposition and τ-p transform.Firstly,the time difference correction is carried out on the monitoring data,and the in-phase axis of the microseismic signal is leveled.Then,the synchrosqueezing S-transform was applied to decompose the leveled data to obtain single-frequency slices.Then,the τ-p transform is performed on each single-fre-quency slice,and the microseismic signal position is obtained according to the results of the τ-p transform.Fi-nally,noise cancellation is completed in the time-frequency domain according to the position of the signal.The processing results of ground microseismic monitoring data with low signal-to-noise ratio show that the new method can obtain ideal noise cancellation results.
关键词
地面微地震监测/微地震信号消噪/同步挤压S变换/τ-p变换/谱分解
Key words
ground microseismic monitoring/microseismic signal denoising/synchrosqueezing S-transform/r-p transform/spectral decomposition
万方数据