无旁瓣伪随机脉冲压缩技术及其应用于可控震源的研究

A STUDY OF SIDELOBELESS PSEUDO-RANDOM PULSE COMPRESSION TECHNIQUE AND ITS APPLICATION TO VIBROSEIS

1. 西安交通大学;2. 江汉石油学院

1. Xi'an University of Communications;2. Jianghan Petroleum Institute

消除线性调频信号可控震源相关子波旁瓣是提高信噪比和地层分辨率的重要途径之一。本文给出了线性调频信号和一类无旁瓣伪随机信号相关子波的数学表达式。以此为基础,利用计算筛选方法进行信号寻优,找到了一种更便于相关处理的完全无旁瓣伪随机脉冲压缩信号。相关处理乘法可简单地用伪随机门控采样(模拟)或伪随机控制数据保留与剔除(数字)方法实现。本文通过计算仿真与超声模拟实验,证实了在可控震源系统中应用无旁瓣伪随机脉冲压缩技术的有效性。

The VIBROSEIS sidelobe elimination by using linear FM (frequency-modulated )signal is considered one of the significant approaches for enhancing S/N ratio as well as stratigraphic resolution. The correlation functions of linear FM signal along with a set of mathematic expressions of suchlike sidelobeless pseudo-random correlative wavelets are given in the paper. Based on which to perform the signal optimization by means of computer screening and hence a kind of pseudorandom pulse compression signal(with no single piece of sidelobe at all)which is apparently easier to do correlation is detected. The multiplication of correlation could be implemented just by pseudo random gating sampling (analog)or data reservation control and rejection (digital). Also, the workability of applying the sidelo-beless pseudo-random pulse compression technique to VIBROSEIS in seismic exploration has been verified through a number of computing practices and ultrasound simulation tests as well.