基于波场延拓的变换坐标转换波静校正  

Transformation coordination converted wave static correction based on wave field continuation

作　　者：张正峰[1] 郭建[1,2] 韩立国[1] 徐善辉[2] 巩向博[1] 

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学报》2013年第5期1676-1685,共10页Chinese Journal of Geophysics

基　　金：国家“863”项目(2008AA062001)和(2012AA060102)联合资助

摘　　要：常规的转换波静校正的基本思想都是从地震波的运动学特征出发,基于地表一致性假设.在地表条件复杂和地表高程相差较大的地区,它不仅无法解决严重的静校正问题,反而会带来新的畸变.本文基于频率波数域波动方程偏移原理,采用波场延拓方法实现转换波静校正,其关键点在于时间空间域和频率波数域的相对应.文中通过坐标变换将起伏地表转化为新坐标系下的水平地表,把炮点和检波点映射到同一水平面上,然后在新坐标系下推导频率域波动方程延拓公式,接着对下行波P和上行转换波SV分别利用近地表速度向上延拓到基准面,恢复起伏地表到基准面之间的真实波场,最后转换到原始坐标系取出基准面数据完成转换波静校正.通过对模拟和实际数据处理,证明该方法是正确和有效的.The basic idea of the conventional converted wave static correction is from the kinematic characteristics of seismic waves,which is based on the surface consistency assumption.In areas of complex surface conditions and big surface elevation differences,it is not only unable to solve the serious problem of static correction,but also to bring a new distortion.The method presented in this paper uses wave field continuation to complete the converted wave static correction,which is based on the frequency-wave number wave equation migration principle.The key point is the relationship between the time-space domain and frequency-wave number.For this problem,firstly,we transform the undulating surface into a horizontal surface under the new coordinate system,which moves the shot and receiver to the same level.Next we derive the wave equation and formula for wave field continuation under the new coordinate system,then continue the down going wave P and the up going converted wave SV up to the datum plane using the near-surface velocity,which can restore the real wave field between the undulating surface and datum plane.At last,we convert it to the original coordinate system to get the P-SV static correction seismic data on the datum plane and complete the converted wave static correction.The results of the processed model and real seismic data prove that this method is correct and effective.

关 键 词：转换波 时间空间域 频率波数域 坐标变换 静校正 

分 类 号：P631[天文地球—地质矿产勘探]