uDAS 分布式光纤传感地震仪及其应用

设计了一种超灵敏分布式声波传感地震仪(uDAS),该仪器以高性能相敏型光时域反射仪为基本构架,利用多频和随机光纤激光放大技术,结合干涉解调方法,实现了瑞利散射光信号相位的精确解调,可用于外界声波/振动信号的高精度拾取。实验结果表明,uDAS在1～500Hz内噪声底达4.5pε/Hz,同时具有线性幅度响应、长距离工作等特征。与电子检波器进行对比测试,二者的记录波形高度一致。uDAS已初步应用于井中地震监测、微测井等勘探作业,获得了高质量的生产资料。此外,uDAS在长期动态监测、管线监测等油气勘探与开发等业务中具有巨大的应用前景。

An ultra-sensitive distributed acoustic sensing (uDAS) seismograph is designed based on a high-performance phase-sensitive optical time domain reflectometer.Multi-frequency and random fiber laser amplification technologies combined with the interference demodulation method are adopted to achieve an accurate demodulation of the phase of the Rayleigh scattered light signal,which can be used for high-precision pickup of external sound waves/vibration signals.Experimental results show that uDAS has a noise floor of 4.5pε/Hz in the range of 1~500Hz.Moreover,it has the characteristics of linear amplitude response and long sensing distance.Compared with those obtained via electronic detectors,the recorded waveforms are highly consistent.uDAS has initially been used in borehole seismic monitoring,micro-logging,and other exploration activities,and has led to high quality production data.Currently,uDAS has great application prospects in petroleum exploration,such as in long-term dynamic monitoring and pipeline monitoring.

国家自然科学基金项目(51875091)资助。