微地震技术在农安油页岩靶区的应用

Application of micro-seismic technology in Nong'an oil shale target region

微地震初至时间拾取是微地震资料处理过程中的一个重要步骤,也是地层速度模型建立的重要依据。为提高拾取精度,本文提出一种新的自动拾取初至时间的方法,计算三分量地震数据的小时窗协方差矩阵特征值,将其作为特征函数引入到STA/LTA能量比法当中,从而实现自动拾取初至时间,并结合P波时差法完成震源定位。理论模型及农安浅井油页岩水力压裂试验的微地震资料处理结果表明,该方法可以有效地拾取微地震初至时间并实现震源定位。

Picking up first break is an important step in micro-seismic data process,and it is the significant gist of velocity model establishment. In order to enhance the precision of pickup,this paper presents a new automatic first break pickup method,by calculating the small time window covariance matrix characteristic value of the three-component seismic data,which can be introduced into the STA / LTA energy ratio method as the characteristic function to realize the first break pickup automatically. After then,combined with the P wave time difference method,the source location in the data process is achieved. The results of the synthetic model and the micro-seismic data of shallow well hydraulic fracturing test of oil shale in Nong＇an indicate that the proposed method can realize the automatic first break picking and source locating effectively.