二维单程波有限差分法叠前时间偏移技术应用  

Pre-stack time migration technology of 2-D one-way wave finite difference method and its application

作　　者：何鑫[1] HE Xin(Research Institute of Exploration Company,SINOPEC,Chengdu 610041,China)

机构地区：[1]中国石化勘探分公司勘探研究院,四川成都610041

出　　处：《复杂油气藏》2020年第3期22-26,共5页Complex Hydrocarbon Reservoirs

基　　金：“十三五”国家科技攻关重大专项(2016ZX05002-004-007、2017ZX05005-004)资助。

摘　　要：叠加、反褶积和偏移是地震数据处理的三大技术。偏移的目的是使倾斜地层成像归位到真实的位置,同时使得绕射波收敛,向斜蝴蝶结回转波打开并归位。偏移的数学本质是在一定边值、初值条件约束下求解波动方程。求解的方法有两大类:积分法和差分法。主流的克希霍夫积分法需要射线追踪,存在射线多值性的问题,而且是高频近似下的解,先天的缺陷使得积分法成像存在焦散、弱信号成像困难和浅层成像差等的缺点;差分法是通过差分逼近微分,用波场延拓的方式完成偏移,不存在射线追踪和高频近似,更接近地震波波动传播的特点。经过实际资料的验证,单程波有限差分法叠前时间偏移比克希霍夫叠前时间偏移成像效果更有优势。Superposition,deconvolution,and migration are three major techniques of seismic data processing.The purpose of the migration is to return the oblique formation imaging to the true position,and at the same time make the diffracted waves converge,and open and return the syncline bow-tie gyration wave.The mathematical essence of migration is to solve the wave equation under certain boundary value and initial value constraints.There are two types of solving methods:integral method and difference method.The mainstream Kirchhoff integration method requires ray tracing.There is a problem of ray variability,and it is a solution under high-frequency approximation.Inherent defects make the integration method imaging have the shortcomings of caustics,weak signal imaging difficulties,and poor shallow imaging.The difference method is to approach the differentiation through difference and complete the migration by wavefield extension.There is no ray tracing and high-frequency approximation,and it is closer to the characteristics of seismic wave propagation.Through the verification of actual data,the one-way wave finite-difference method pre-stack time migration has more advantages than the Kirchhoff pre-stack time migration imaging effect.

关 键 词：偏移 波动方程 克希霍夫 有限差分 

分 类 号：P631[天文地球—地质矿产勘探]