A comprehensive picking method for p-wave first arrival point of microseismic signal

Abstract

The invention discloses a method for comprehensively picking up the first arrival point of a microseismic signal P wave, comprising the following steps: importing microseismic time series data; picking the first threshold trigger point k1 of the STA / LTA method; picking the maximum kurtosis point of the PAI‑K method k2; pick AIC method autocorrelation minimum value point k3; comprehensive method to determine the first arrival point k of P wave: (1) when k1 is not picked up, take k=k3; (2) when k1 is picked up: ①|k1‑k3|≤ a, take k=k3; ②|k1‑k2|≤a, and |k1‑k3|>a, take k=k2; ③|k1‑k2|>a, and |k1‑k3|>a, take k =k1. The comprehensive picking method effectively solves the technical problems of STA / LTA method with many non-picking events, low picking accuracy, and poor picking stability of PAI-K method and AIC method. This method has the characteristics of simple processing, strong applicability and high accuracy.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and in particular relates to a method for comprehensively picking up the first arrival point of a P wave of a microseismic signal. Background technique [0002] As an advanced and effective means of regional disaster monitoring and prediction, microseismic monitoring technology has been widely used in mining engineering, oil and gas exploitation, slope stability and tunnel engineering at home and abroad. Microseismic monitoring technology mainly includes: monitoring network layout, data processing, and microseismic event location (Ge, 2005), and picking the P wave first arrival point of microseismic signals is one of the core tasks of data processing. At present, the first arrival point of P wave is mainly picked manually, but the efficiency of manual picking is low and it is easily affected by personal factors. For this reason, it is very important to develop a high-precision and stab...

AI Technical Summary

Problems solved by technology

The STA / LTA method utilizes the changes in the amplitude and frequency of the microseismic signal at the first arrival point of the P wave. This algorithm is simple and easy to understand, and the calculation speed is fast. The signal is easily triggered by noise in advance; when the threshold value is large, the microseismic signal may not be triggered or triggered late, resulting in a large error, so it is difficult to find a threshold value suitable for different waveforms

The PAI-K method and the AIC method make full use of the singularity of the microseismic signals before and after the first arrival of the P wave, and the picking accuracy is high ( image 3 and Table 2), but are susceptible to low signal-to-noise ratios, spikes, and tail oscillations ( figure 2 ), poor pickup stability

[0004] It can be seen that there are great limitations in the existing methods for picking the P-wave first arrival point of microseismic signals, and it is necessary to study an automatic picking method with high picking accuracy and good stability

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