弹性波逆时偏移子波拉伸校正Wavelet Stretch Correction in Elastic Wave Reverse Time Migration
杨绍伟,何兵寿,杨佳佳
摘要(Abstract)：
弹性波逆时偏移的子波拉伸效应是指偏移后纵横波在垂向(深度)上的子波延续长度和频率随地震波速度、地层倾角和反射角的变化而变化。通过研究弹性波逆时偏移中的纵、横波子波拉伸效应,提出了相应的校正方法:提取弹性波延拓过程中各成像点在成像时刻的震源波场和接收点波场的地震子波,以不改变成像结果的振幅与相位为前提,在波场延拓后,应用成像条件前对纵横波进行子波压缩处理,消除地震波速度、地层倾角和反射角等因素对纵横波延续长度和频率的影响。数值算例表明,该方法可提高逆时偏移后纵横波的垂向分辨率与振幅保真性,为后期进行AVO/AVA或其它叠前反演工作提供输入数据。
关键词(KeyWords)： 弹性波;逆时偏移;子波拉伸校正;分辨率;AVO分析
基金项目(Foundation): 国家自然科学基金资助项目(41174087,41204089);; 国家科技重大专项项目(2011ZX05005-005);; 863项目(2013AA064201)
作者(Author): 杨绍伟,何兵寿,杨佳佳
参考文献(References)：
- [1]Loewenthal,D.,Mulfti,I.R.,1983,Reverse time migration in spatial frequency domain,Geophysics,46(3):627-635.
- [2]Mc Mechan,G.A.,1983,Migration by extrapolation of time-dependent boundary values,Geophys Prosp,31(2):413-420.
- [3]王胜,何兵寿,陈婷.任意广角方程逆时偏移的脉冲响应及模型试算[J].中国煤炭地质,2014(2):49-54.
- [4]Zhu X F.Migration and inversion of long-offset,large-angle reflections.Ph.D.dissertation,The University of Texas at Dallas,2013.
- [5]Tygel M,Schleicher J and Hubral P.Pulse distortion in depth migration.Geophysics,1994,59:1561-1569.
- [6]Roy B,Anno P and Durrani J.Analytic correction for wavelet stretch due to imaging.75th Annual International Meeting,SEG,Expanded Ab?stracts,2005,234-237.
- [7]Perez G and Marfurt K.Correcting for wavelet stretch in common-an?gle migration improves vertical and lateral resolution.SEG Technical Program Expanded Abstracts,2006,254-258.
- [8]Canning A and Malkin A.Removing NMO/Migration stretch effects for improved AVO analysis.7th International Conference&Exposition on Petroleum Geophysics,2008,366-370.
- [9]Zhu X F and Mc Mechan G A.Stretch-free migration imaging condi?tion.Geophysics,2013,78(4):203-210..
- [10]Chen Ting and He Bingshou.A normalized wavefield separation cross-correlation imaging condition for reverse time migration based on Poynting vector.Applied geophysics,2014,11(2):158-166.
- [11]Jin,H.,Mc Mechan,G.A.,and Guan,H M.,Comparison of methods for extracting ADCIGs from RTM.Geophysics,2014,79(3):89-103.