地震数据采集系统频谱均衡滤波理论研究

Study on the Theory of Spectrum Equilibrating Filter in Seismic Data Acquisition System

建立视等厚层状吸收介质模型,计算地层吸收衰减特性,以此为依据给出了频谱均衡滤波器的数学模型和设计框图。选择主频为200 Hz的雷克子波,理论计算原始地震反射波的特征参数(主振幅、主频率、频带宽度)。利用所设计的频谱均衡滤波器对原始地震反射进行滤波,能够有效补偿地层的吸收衰减,地震反射波的特征参数得到明显改善。时间从0.5～3.0 s,主振幅增强了20.55～30.40 dB,主频率提高了104～74 Hz,频带被拓宽了205～186 Hz,分辨率提高到2.9～13.9 m(分辨率提高了56%～67%)。

A set of uniform thickness models of layered absorption media were established. The absorption and attenuation character of stratum were calculated as well. Based on these results the mathematic model and spectrum equilibrating filter （SEF） frame were designed. Ricker wavelet whose predominant frequency is 200Hz was chosen as the exciting wave, and the character parameters （predominant amplitude,predominant frequency and frequency bandwidth） of its reflected wave were calculated. Filtered by SEF the strata＇s absorption and attenuation was compensated and the parameters of reflected wave could be improved as well. When time range changed from 0.5s to 3.0s, the predominant amplitude, predominant frequency and frequency band increased 20.55-30.40 dB , 104-74 Hz and 205-186 Hz , respectively, and the resolution increased to 2.9-13.9 m（increasing 56%-67%）.