Abstract：Geophone array is used to suppress random noises and regular noises and improve signal to noise ratio,especially in those prospects with low signal to noise ratio.Array parameter design is commonly performed under the assumption that seismic waves are harmonic waves at a specific frequency.Element interval,number of arrays,weighing factor,and time delay have not been taken into overall consideration; this results in significant low-pass filtering and distorted AVO effects.We discuss the relations among above 4 parameters and orientation factor at complex frequencies.To calculate the theoretical signal to noise ratio,we formulate an equation and then take it as the objective function for array parameter design through global optimization.As per model and field data tests,linear noises and random noises could be greatly reduced using the time-delay weighted arrays with above 4 optimized parameters; the behavior of low-pass filtering and AVO distortion could also be remedied.
Klipsch P W.Some aspects of multiple recording in seismic prospecting[J].Geophysics,1936,1(3):365-377.
[2]
Johnson C H.Steady state polar sensitivity curves[J].Geophysics,1939,4(1):33-52.
[3]
Dean T,Dupuis J C and Hassan R.The coherency of ambient seismic noise recorded during land surveys and the resulting implications for the effectiveness of geophone arrays[J].Geophysics,2015,80(3):P1-P10.
Rietsch E.Geophone sensitivities for Chebyshev optimized arrays[J].Geophysics,1979,44(6):1142-1143.
[6]
Simaan M.Optimum array filters for array data signal processing[J].IEEE Transactions on Acoustics Speech & Signal Processing,1983,31(4):1006-1015.
[7]
Hanna M T.Multiple signal extraction by multiple interference attenuation in the presence of random noise in seismic array data[J].IEEE Transactions on Signal Processing,2003,51(7):1683-1694.
[8]
Johnson K R.Correlation function of teleseismic noise[J].Bulletin of the Seismological Society of America,1968,58(2):521-538.
[9]
King D W,Mereu R F and Muirhead K J.The mea-surement of apparent velocity and azimuth using adaptive processing techniques on data from the warramunga seismic array[J].Geophysical Journal of the Royal Astronomical Society,1973,35(1-3):137-167.
[10]
Mao W J and Gubbins D.Simultaneous determination of time delays and stacking weights in seismic array beamforming[J].Geophysics,1995,60(2):491-502.
[11]
Bagaini C.Performance of time-delay estimators[J]. Geophysics,2005,70(4):V109-V120.
张鹏,杨凯,李欣,等.海上空气枪点震源阵列的优化设计及应用[J].石油地球物理勘探,2015,50(4):588-599.ZHANG Peng,YANG Kai,LI Xin,et al.The optimal design of point source air-gun array in marine and its application[J].Oil Geophysical Prospecting,2015,50(4):588-599.
[14]
何宝庆,谢小碧.宽线地震数据采集和处理的数值模拟[J].石油地球物理勘探,2019,54(3):500-511.HE Baoqing,XIE Xiaobi.A numerical investigation on wide-line seismic data acquisition and processing[J].Oil Geophysical Prospecting,2019,54(3):500-511.
[15]
姜弢,林君,杨冬,等.相控震源定向地震波信号分析[J].地球物理学报,2008,51(5):1551-1556.JIANG Tao,LIN Jun,YANG Dong,et al.Analysis of directional seismic signal based on phased-array vibrator system[J].Chinese Journal of Geophysics,2008,51(5):1551-1556.
[16]
徐峰,刘福烈,梁向豪.基于相控理论的炮点组合设计技术[J].石油地球物理勘探,2011,46(2):170-175.XU Feng,LIU Fulie and LIANG Xianghao.A method for source array design based on the phased-array theory[J].Oil Geophysical Prospecting,2011,46(2):170-175.
