浅水无定位拖缆观测系统定义及多次波压制效果分析  

Definition of seismic geometry for short non-position receivers and multiples attenuation in shallow water

作　　者：丁维凤 李家彪[2] 高金耀[2] 杨春国[2] 纪飞[2] 袁园[2] DING Wei-Feng LI Jia-Biao GAO Jin-Yao YANG Chun-Guo JI Fei YUAN Yuan(College of Marine Geosciences, Ocean University of China, Qingdao 266100, China Second Institute of Oceanography, SOA, Hangzhou 310012, China)

机构地区：[1]中国海洋大学海洋地球科学学院,青岛266100 [2]国家海洋局第二海洋研究所海底科学重点实验室,杭州310012

出　　处：《地球物理学报》2017年第9期3685-3692,共8页Chinese Journal of Geophysics

基　　金：东亚大陆边缘现代地质过程与致灾机理专项研究(GASI-GEOGE-05);国家自然科学基金(41576069)及2017年度南极周边海域海洋地球物理考察(CHINARE2017-01-03)联合资助

摘　　要：浅水无定位拖缆在近岸海洋工程及浅水多道地震勘探中应用广泛,但受无定位拖缆实际位置获取的限制,野外观测系统准确定义受影响.基于传统直线假设的观测系统定义简单易行,但计算的共反射点面元无法获得实际坐标,位置偏差较大,严重影响后续处理方法的有效应用.基于实际炮点轨迹坐标,本文提出了一种新的无定位拖缆实际坐标计算方法,新方法首先确定接收排列的相对空间位置,采用反距离比线性插值算法准确计算接收道实际坐标值,再根据实际坐标重新定义观测系统,获得了实际跑航弯曲测线观测系统图.文中对传统方法与新方法定义的不同观测系统数据,分别采用SRME(Surface-related Multiple Elimination)方法压制浅水海底鸣震类自由表面相关多次波,结果显示采用新方法定义的观测系统反射数据多次波衰减效果明显,有效反射连续,基底反射成像清晰,说明文中实际坐标计算方法符合海上弯曲测线观测系统的定义,提高了SRME方法压制多次波的效果.Defining the precise seismic geometry is very important for seismic data processing and interpretation. The short receiving cable with a non-position device is widely used in seismic exploration in shallow water, while its geometry definition meets some problems when processing the seismic data without the actual GPS position. Because it is difficult to acquire the true position information for the non-position cable in field prospecting, we usually rely on the assumption based on traditional linear geometry. The traditional method is simple to use, but it cannot get the actual X and Y coordinates and produces some errors in the CMP （Common Middle Point） location and the result of stacked folds, that seriously affects the subsequent modules＇ processing, such as the SRME method to attenuate surface-related multiples as reverberation, in which the energy is very strong in shallow water＇s seismic data, affecting the interpretation of actual reflector events. To avoid the error in the traditional method based on the linear geometry assumption, we propose a new algorithm to define the non-position short cable receivers＇ geometry. Based on the actual precise shots＇ track line position, this new method first determines the short cable receivers＇ relative space to the shots＇ track line. Then it uses the inverse distance ratio and linear interpolation algorithm to calculate the actual X and Y coordinates of each receiver in the short cable. Next we use these actual shots and receivers＇ X and Y coordinates to precisely define the crooked geometry, which is adapted to the actual crooked lines＇ situation. In order to check the reliability of such a definition for seismic geometry, we use the actual non-position short cable＇s seismic data from the Dongji Island in the offshore Zhoushan area to test the traditional method and the new algorithm. The results show that when using the new algorithm to define the actual seismic data geometry, SRME can effectively attenuates the surface-related multiples such a

关 键 词：无定位 观测系统 反距离比 多次波 SRME 

分 类 号：P631[天文地球—地质矿产勘探]