First Arrival Time Auto-Picking Method Based on Multi-Time Windows Energy Ratio

Abstract

First arrival time auto-picking technique plays an important role in seismic exploration. It is widely used in shallow layer tomography and static correction. Conventional method that based on sliding time windows energy ratio is not stable. Here a new method based on multi-time windows energy ratio is proposed. Combining with automatic quality control and phase-domain first arrival estimation technique, our method performs perfectly on seismic records of normal S/N ratio. In the computational process of conventional sliding time windows energy ratio method, first arrivals are often determined by the maximum energy ratio of two adjacent sliding time windows. It is well known that for low S/N ratio data the conventional picking is not effective, and for high S/N ratio data weak reflections are hardly detected. The reason is that first arrival time does not correspond to the maximum energy ratio. Meanwhile conventional method sometime picks local secondary extreme of energy ratio. The new method of multi-time windows energy ratio method takes both maximum and local secondary extreme in consideration. Hence new method promotes the stability and accuracy of first arrival picking. Combined with automatic quality control and phase-domain first arrival estimation, the new method performs well in its application in the middle part of Dzungarian Basin(Northwest China).