激发信号与反射信号的主频、振幅衰减及分辨率

The dominant frequency, amplitude-attenuation and resolution of excited signal and reflected signal.

从大庆长垣南地区层状地质模型入手,选择Ricker子波为激发信号,主频从50-300Hz系列变化,根据各层的v0和β值计算地层的均方根速度,由均方根速度换算层速度。在此基础上,理论计算了T06,T1,T2,T3和T4-5各层位地震反射信号的主频、振幅衰减及地震垂向分辨率。计算结果表明,24位遥测地震仪能够有效记录T1,T2,T3和T4-5地震反射信号时,激发信号的主频率不应超过270,165,117,102 Hz;激发信号主频在175 Hz以内,提高激发信号的主频能够有效提高反射信号的主频和分辨率;激发信号主频超过175 Hz,反射信号的主频和分辨率不再提高,并且趋于稳定,此时反射信号的主频分别为65,54,41,36,35 Hz,分辨率分别为8.69,10.91,17.98,29.51,37.46m。

Based on the layered geologic model of the area in south of Daqing and according to the values of v0 and β of every stratum, the rms velocity and interval velocity are calculated. Ricker wavelet whose dominant frequency varies from 50 Hz to 300 Hz is chosen as the excited signal. The dominant frequency, amplitude-attenuation of and resolution power of the signal reflected from T06 T1 , T2 , T3 and T4-5, stratum are calculated theoretically. The result shows that when the reflected signal can be recorded by 24-wit telemetric seismic instrument effectively the maximal dominant frequency of excited signal is 270Hz, 165 Hz, 117 Hz and 102Hz respectively (corresponding stratum is T1 , T2 , T3 and T4-5 ). If the excited signal is over 175Hz, the dominant frequency and resolution power won't increase any longer and become stable. At this moment the reflected signal's dominant frequency is 64 Hz, 54 Hz, 41 Hz, 36 Hz and 35 Hz and resolution power is 8. 69m, 10. 91m, 17. 98m, 29. 51m and 37. 46m respectively.