微破裂向量扫描技术的自动化数据处理

Data processing automatically in vector scanning for microseismic

本文是微破裂向量扫描技术(Vector Scanning—VS)系列文章的第四篇.前三篇分别为微地震压裂监测技术研发进展、VS的原理、VS的数据采集(见本文参考文献).为满足微震监测中应用VS的必要条件,即获得小振幅的随机记录,在数据处理中,必须数值化地判断凸显的、或隐藏在背景噪声中的有规律的干扰.目标区内外与监测目标无关的干扰记录被视为外来能量,应去除或压制.换言之,依然是尽力提高有效信噪比.数据处理的主要任务是:处理准备,包括扫描几何设计、构建监测目标区的速度模型、与计算扫描体内各点的地震波射线传播到达各观测点的走时和入射参数表;判别、去除、和压制各类干扰噪声;及完成扫描计算.作为去噪后达到的目标,小振幅的随机背景记录应当是:远处无穷个振源及观测点附近弱电磁场干扰的组合,是无规律或时空上不可预报从而也不可能去除的波动;这些背景噪声的振幅应尽可能的小;有效频率带内,每个频率携带有差别不大的能量密度,即接近白噪声.因而,在时间、频率、和空间域,必须在去噪过程中搜寻、压制或去除下列干扰:任何在周期上可能重复的记录;任何携带较高能量的窄带频率;凸显的任何较大振幅;以及除有用信号外,台站间可能相关的其他记录;等等.要实现数据处理的工程化,主要是软件的高度自动化,需要将VS的必要条件、物理等科技知识、经过验证的观测结论、和计算经验实现数值化,融入到一个专家系统中.

This is the 4th in a series of papers of the vector scanning（ VS） technique for microseismic. The first three are the development of microseismic monitoring for hydro-fracturing,the principle,and the Data acquisition of VS（ see References）. To satisfy the necessary condition of applying VS,which is that all of the records have to be random with small amplitudes,we have to identify any visible or hidden regular interferes in background noise.Any relatively greater outside energy from the sources associated without our monitoring target should be removed in the processing.Our processing progress covers the jobs：（ 1） the preparation,including a scanning geometric design, making a 3D velocity model,and calculating a corresponding travel time table between each pair of station and scanning point for whole target volume;（ 2）the data filtering,including band pass and reject,removing periodic records and those interferes with larger amplitudes; and（ 3） the vector scanning. We have integrated numerically,as more as we can,the knowledge of the necessary condition of applying VS,the mathematics and physics, the observation and calculation experiments,the communication between internet, microseismic and telecommunication networks, etc. in an expert system for automatically data acquisition and processing.