Comparison of picking method of microseismic first-break

Accurate picking of first breaks is one of the key technology of microseismic location. The paper analyzes the principle of STA/LTA, AIC, fractal dimension of three kinds of microseismic first-break picking method, presents a detailed test and verification of the simulation data, and compares first-break picking accuracy and efficiency of the three algorithms through actual data with different S/N ratio. The results show that for the data with high S/N ratio, first break picking accuracy of three methods is relatively high. When SNR decreases, first-arrival time that fractal dimension method picks has higher precision and good noise immunity. However, fractal dimension method has lower efficiency and is limited by algorithm principle, it is difficult to separately pick first breaks for fractal dimension and AIC method. So it is a very good method to identify microseismic events and determine preliminarily the time range of first breaks by STA/LTA method, then to pick first-arrival accurate time by AIC method.