南黄海中部浅水区多次波衰减技术及其效果分析

摘要

In the shallow area,the seabed related multiples can't be depressed effectively by use of conventional SRME method because of the shallow water depth and the lack of reflected signal from the seabed.Predictive deconvolution is often used for multiple wave sup⁃pressing,but deconvolution will destroy valid reflected signal whose wave cycle is similar to the seabed multiple;particularly in the hard seabed,the amplitude of the seabed multiple wave energy is stronger than the seabed reflection, and in this case,the method of predic⁃tive deconvolution cannot depress seabed related multiples entirely.In this paper,seabed related multiples depression by using the DWD+ SRME combination method and DWD method is adopted for attenuating short period seabed related multiples,and the SRME method is used for suppressing long period free surface related multiples.In addition,the method of radon transform is used for removing inter layer multiples.The results show that the seabed related multiples have been depressed effectively by the combination method of DWD+SRME,and the shallow effective reflection signals are not harmed,the deep reflection signals appear gradually because interlayer multi⁃ples are attenuated by using Radon transform method.It is therefore held that the adoption of the combination method of DWD + SRME and Radon transform technique is a feasible multiple depression technique for the low SNR seismic data in the shallow water.%在浅水区，由于水深较浅，缺少近偏移距的海底反射信号，采用常规SRME方法和预测反褶积不能有效地衰减海底相关多次波。笔者采用DWD＋SRME组合法来衰减海底相关多次波，其中DWD方法用来衰减与海底相关的短周期多次波，SRME方法压制自由表面相关的长周期多次波，另外运用Radon变换去除层间多次波。结果表明，运用DWD＋SRME组合法压制海底相关多次波效果较好，并且没有损害浅层的有效反射信号，采用Radon变换使层间多次波得到了良好的压制，深部有效反射信号逐步体现。因此，对于浅水区低信噪比地震资料，采用DWD＋SRME组合方法和Radon域去多次，是比较可行的去多次波方法。