单船拖曳可控源电磁数据自适应分频匹配滤波消噪方法  

Denoising single-ship towed MCSEM data with adaptive frequency-division matching filter

作　　者：崔扬 刘洋[1] 殷长春[1] 王典[1] 惠哲剑 CUI Yang;LIU Yang;YIN ChangChun;WANG Dian;HUI ZheJian(College of Geo-exploration Science and Technology,Jilin University,Changchun 130026,China)

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026

出　　处：《地球物理学报》2023年第4期1732-1742,共11页Chinese Journal of Geophysics

基　　金：国家重点研发计划课题(2016YFC0303101);国家自然科学基金项目(41774127)资助

摘　　要：海洋可控源电磁法(MCSEM,Marine Controlled-Source Electromagnetic Method)是一种工业化的主动源海洋电磁勘探方法,近年来在海底油气资源探测中收效显著,通过测量海底地下介质的电阻率变化,能够有效降低地震勘探方法的多解性.MCSEM的工作方式主要有单船拖曳与双船拖曳两类.单船拖曳信号具有强时变特征,近、中、远收发距信号强度变化极大.由于海水环境较为复杂,数据受到洋流、背景场、仪器等多种因素干扰,使得小收发距数据信噪比较高,中、远收发距数据信噪比较低,因此MCSEM数据随机干扰压制方法的研究难点在于适应数据的强时变特征.本文利用发射机数据与接收机数据的时间(空间)和频率对应关系,提出基于正则化条件和衰减函数约束的自适应分频匹配滤波方法.该方法首先通过计算原始接收机数据基频的振幅随偏移距变化(MVO,Magnitude Versus Offset)曲线获取衰减函数,然后利用该衰减函数将发射机所有频点数据进行振幅衰减,减低MCSEM发射机与接收机数据对应振幅的强时变差异,最后利用基于整形正则化条件的自适应匹配滤波方法压制接收机数据中的强振幅随机噪声.模型数据与实际数据的处理结果表明,本文提出的方法能够有效压制MCSEM数据中不同收发距的随机噪声干扰,保护具有强时变特征的接收机数据,提升整体数据质量.The Marine Controlled-Source Electromagnetic Method(MCSEM)is an industrialized marine Electromagnetic(EM)exploration method that has achieved remarkable results in the exploration of offshore oil and gas resources in recent years,by measuring the resistivity variation of the seabed media,the multi-solution of seismic exploration methods can be effectively reduced.MCSEM mainly works in single ship towing and double ship towing manner.The single ship towing EM signal has a strong time-varying characteristic,and the amplitude of EM signal varies greatly with transmitter-receiver offsets.Due to the complicated environment in the ocean environment,the data are interfered by various factors such as ocean current,background field and instrumental noise,which makes the SNRs of the data for small transmitter-receiver offsets are very high,while the SNRs of the data for medium to large transmitter-receiver offsets are very low.Therefore,the difficulty of the research of suppressing random noise of MCSEM data lies in adaptation to the strong time-varying characteristics of data.In this paper,the time(space)and frequency correlation between transmitting and receiving data is used to deal with the strong time-varying characteristics of MCSEM signal by using adaptive frequency-divided matched filter based on regularization condition and attenuation function constraints.The attenuation function of receiving data is obtained by calculating the fundamental frequency Magnitude Versus Offset(MVO)curve of the original receiving data,and the attenuation function is used to attenuate the amplitude of all transmitting data at different frequencies to reduce the strong time-varying difference between the amplitude of the MCSEM transmitting and receiving data.Finally,the adaptive matched filtering method with regularization conditions is used to suppress the strong random noise of amplitude in the receiving data.The processing results of synthetic and field survey data show that the method presented in this paper can effectively suppress

关 键 词：海洋可控源电磁方法 单船拖曳 随机噪声压制 衰减函数 自适应分频匹配滤波 

分 类 号：P631[天文地球—地质矿产勘探] P738[天文地球—地质学]