两种类型共炮点域相关型叠前深度偏移方法分析  

STUDY ON TWO TYPES OF CORRELATION PRE-STACK DEPTH MIGRATION METHODS IN COMMON SHOT DOMAIN

作　　者：陈可洋[1] 

机构地区：[1]中国石油大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《内陆地震》2012年第1期17-27,共11页Inland Earthquake

基　　金：国家重点基础研究发展计划(973)资助项目(2009CB219307)

摘　　要：研究不同偏移方法的成像机理是实现复杂构造高精度成像的前提,研究了两类共炮点域的相关型叠前深度偏移成像方法:基于单程波动方程的叠前深度成像方法和基于双程波动方程的叠前深度成像方法,同时对比了它们在计算效率、数据存储量、成像精度、成像机理、速度敏感性等方面的差异及其共性。以复杂构造模型为例,采用了傅里叶有限差分法(FFD)和逆时成像法(RTM),这两种方法实现了121个共炮点道集的叠前深度偏移成像处理。计算结果表明,当速度准确时,两种深度域波动方程成像方法均可以恢复出各个地质反射界面,其中逆时偏移对陡倾角成像效果显著,当速度存在百分比误差和随机扰动情况时,逆时成像结果要差于单程波方法,因此,逆时偏移方法对速度的敏感性较大,且低频噪声较为严重。Research on different migration methods of imaging mechanism is precondition of high accuracy complex structure imaging accomplishment.This paper studied two types of correlation pre-stack depth migration methods in common shot domain： pre-stack depth migration method based on one-way wave equation and two-way wave equation.The difference between these two methods was compared such as ：computational efficient、 storage amount、imaging precision and imaging mechanism.Taking complex structure model as an example,this paper carried out the pre-stack depth migration with Fourier finite difference method（FFD） and reverse-time migration method（RTM） on 121 common shots gathers simulated from the complex velocity model.The numerical results showed that： two methods can effectively imaging complex medium structure with correct migration velocity,in which RTM method achieved better results within large dip area.However,two-way wave imaging method got worse results than FFD method when migration velocity has percentage error or random disturbance and RTM method is more sensitive with serious low-frequency noise.

关 键 词：共炮点域 单程波成像方法 双程波成像方法 相关型成像条件 叠前逆时偏移 

分 类 号：P315.259[天文地球—地震学]