一种多波宽频地震数据采集设计与仪器实现关键技术  

Design of multi-wave broadband seismic data acquisition and key technology

作　　者：刘勇[1,2] 庹先国[1,2,3] 李怀良[1,3] 沈统[1,2] 陆景[2,3] 

机构地区：[1]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059 [2]四川理工学院,四川自贡643000 [3]核废物与环境保护国防重点学科实验室(西南科技大学),四川绵阳621010

出　　处：《地球物理学报》2017年第11期4302-4312,共11页Chinese Journal of Geophysics

基　　金：自然科学基金重大科研仪器设备研制专项"复杂山地多波宽频带地震数据采集系统研制"(41227802);自然科学基金应急管理项目(41641041)资助

摘　　要：随着多波多分量技术的发展,宽频数据采集逐渐成为地震勘探的发展趋势.通过高保真获取全波场信息,并尽可能保留高频有效成分,进而利用多种波场信息相互验证和补充,是提高地震勘探精度的有效方法.受仪器带宽限制,常规设备在高频段很难同时保持高分辨率和大动态范围特征,在多波地震采集时,极容易出现分辨率不足和限幅失真等现象,极大影响多波多分量方法的实际应用效果.鉴于此,本文给出一种利用积分器、高频ADC、DAC和抽取滤波器构成的低成本宽频数据采集方法.通过构造环路滤波器(调制器),对高频ADC输出数据中的量化噪声二次整形,并配合抽取滤波,对带外噪声进行有效压制.实际测试表明,通过精细电路结构设计,采集站有效分辨率可达24位(采样率为2 kHz),动态范围超过140 dB,SNR达142 dB.相比传统设备,其采集数据在5～25 Hz的低频段和100 Hz以上的高频段都具有更加丰富的有效信息,非常适合多波多分量数据采集.In the field of seismic exploration, multi-wave and multi-component technology is widely used and broadband data acquisition has gradually become a trend. By obtaining the full wave field with high frequency component preserved, verifying and supplementing each other with various wave field, it can be an effective method to improve the accuracy of exploration. Limited by bandwidth, conventional equipment cannot maintain high resolution and large dynamic range when it works at high frequency, which will lead insufficient resolution and limiting distortion. Given all that, this paper presents a low-cost broadband data acquisition method. Specifically, the loop filter （modulator）, constructed by an integrator, a high frequency ADC and DAC, is used to shape the quantization noise caused by ADC. In addition, the CIC filter, the half-band filter and the FIR filter are used to construct the decimation filter to suppress the out-of-band noise. The result shows that the resolution of the acquisition station can reach 24 bits （sampling rate of 2 kHz）, while the dynamic range is of more than 140 dB and SNR is up to 142 dB as well. Moreover, the effective information is richer both at low （5~25 Hz） and high frequency （〉100 Hz）. Compared with the traditional equipment, the design is suitable for multi-wave and multi-component data acquisition.

关 键 词：多波勘探 宽频采集 动态范围 量化噪声 地震数据采集系统 

分 类 号：P631[天文地球—地质矿产勘探]