反射波振幅谱特征与地震仪前置放大器设计  

The Characters of Amplitude Spectrum of Reflected Wave and the Design of Pre-amplifier in Seismic Instrument

作　　者：袁子龙[1] 李婷婷[1] 

机构地区：[1]大庆石油学院,大庆163318

出　　处：《仪器仪表学报》2006年第2期137-140,共4页Chinese Journal of Scientific Instrument

基　　金：黑龙江省自然科学基金(E0317);黑龙江省教育厅科学技术研究(10543003)资助项目

摘　　要：由于地层吸收衰减及球面扩散,使得深层地震反射波的振幅衰减严重,导致地震仪记录信号的有效动态范围远小于120dB,满足不了高分辨率地震勘探对记录信号动态范围的要求。从视等厚层状吸收介质模型入手,理论计算了地震反射波的振幅谱。其特征分析表明:反射波振幅随深度的增加按指数规律衰减,但衰减主要发生在1.5s前的中浅层。设计了智能程控型前置放大器,它的增益随深度增加自动增大,其值依次为0dB、18dB、24dB、30dB、36dB和42dB,使深浅层地震反射波的振幅在记录前均得到适当补偿,确保了地震仪记录信号的有效动态范围接近120dB,这对高分辨率地震勘探理论和开发新一代地震仪具有重要意义。By the absorption of earth and the spherical diffusion the attenuation of amplitude in deep layer is serious, so the actual dynamic range of seismic instrument is much lower than 120dB which can＇t meet the needs of high resolution seismic exploration. Starting from the layer absorbing media model, the amplitude spectrum is calculated theoretically. By analyzing those characters it can be known that the amplitude of reflected wave attenuates according to the rule of exponent and the attenuation happens mainly in the medium depth. The intelligent programming pre amplifier is also designed whose gain （0dB, 18dB, 24dB, 30dB, 36dB and 42dB） can in crease with the increment of depth automatically. Thus the amplitude of reflected wave can be compensated before recording and the actual dynamic range of seismic instrument is close to 120dB which bears important mean ing to the theory of high resolution and to developing new generation of seismic instrument.

关 键 词：地震反射波 振幅谱地层吸收 动态范围 地震仪 前置放大器 

分 类 号：P631.4[天文地球—地质矿产勘探]