一种利用低频反鬼波滤波器提升深部地震信号能量的方法  

A method to enhance the energy of deep seismic signals by using low-frequency deghosting filter

作　　者：成谷 张宝金[3] 刘玉萍[3] CHENG Gu;ZHANG Baojin;LIU Yuping(School of Earth Science and Engineering,Sun Yat-sen University,Zhuhai 519082,China;Guangdong Provincial Key Laboratory of Mineral Resources&Geological Process,Zhuhai 519082,China;Guangzhou Marine Geological Survey,China Geological Survey,Guangzhou 511458,China)

机构地区：[1]中山大学地球科学与工程学院,广东珠海519082 [2]广东省地质过程与矿产资源探查重点实验室,广东珠海519082 [3]中国地质调查局广州海洋地质调查局,广东广州511458

出　　处：《中山大学学报（自然科学版）（中英文）》2024年第5期1-12,共12页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：广东省自然科学基金(2016A030313311)。

摘　　要：海洋地震勘探中鬼波的存在压制了信号中的低频能量,而地球深部结构主要对应低频信号成分,提升受到鬼波压制的低频成分对深部结构探测具有重要意义。鬼波压制过程的关键参数之一是鬼波与一次反射波的到时差,其精度直接影响鬼波压制的效果。受起伏海面、崎岖海底、反射层深度变化和不均匀体分布等因素的影响,鬼波与一次反射波的到时差常无法准确估计,导致鬼波压制无法取得较好的效果。本文在鬼波与一次反射波到时差估计不准的情况下,从反鬼波滤波器的特性出发,设计不扰动高频、仅提升低频的滤波器,绕开对鬼波的压制,仅致力于对低频信号的能量提升。模型测试结果表明:利用本文方法处理后的波形,在形态上接近于无鬼波干扰的一次反射波形,且地震信号主频越低、拖缆的沉放深度越小,本方法对低频信号的能量提升作用越强。在南海实测深反射地震剖面上的测试应用也取得了较好的效果。The presence of ghost waves suppresses the low-frequency energy of signal acquired in marine seismic exploration,while deep structures of the earth mainly correspond to the low-frequency signal components,thus,it is of great significance to improve the low-frequency components suppressed by ghost waves for the detection of deep structures.One of the key parameters of ghost wave suppression is the arrival time difference between the ghost wave and the primary reflected wave,and its accuracy directly affects the effect of ghost wave suppression.Due to the influence of factors such as undulating sea surface,rugged seabed,depth change of reflective layer,and distribution of inhomogeneous media,the arrival time difference between the ghost wave and the primary reflected wave can often not be accurately estimated,resulting in the failure to achieve good results in ghost wave suppression.In this paper,based on the characteristics of the deghosting filter,a filter that does not disturb the high frequency and only improves the low frequency is designed to bypass the suppression of the ghost wave and only focus on the energy improvement of the low-frequency signal.The results of model tests show that the waveform processed by the proposed method is morphologically close to the primary reflected waveform without ghost wave interference.Moreover,the lower the dominant frequency of the seismic signal and the smaller the sinking depth of the towing cable,the stronger the energy enhancement effect of this method on the low-frequency signal.A test applied in the deep reflection seismic profile of the South China Sea has also attained good performances.

关 键 词：低频提升 鬼波压制 深部结构探测 海洋地震勘探 

分 类 号：P631.4[天文地球—地质矿产勘探]