基于高阶有限差分的波动方程叠前逆时偏移方法

2009年 48卷 第No. 5期
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Wave equation pre-stack reverse-time migration method based on high-order finite-difference approach
(大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712)
Exploration and Development Research Institute,Daqing Oilfield Company Limited,Daqing 163712,China
高阶有限差分波动方程叠前逆时偏移方法的基本原理是,从二维1阶双曲型地震波波动方程出发,通过时间上的2阶差分和空间上的任意高阶交错网格差分对该方程进行离散,得到高阶有限差分逆时偏移算子。采用单频双程波动方程计算初至走时,并以此作为叠前逆时深度偏移的成像条件。设计了凹陷模型和断陷模型,对方法进行了验证。模拟结果表明,基于高阶有限差分的波动方程叠前逆时深度偏移方法可以对复杂地层进行准确成像,并能消除由逆时偏移引起的低频噪声。
The principles of wave equation pre-stack reverse-time migration method with high-order finitedifference approach are as follows:starting from 2D first-order hyperbolic seismic wave equation,the equation was discrete by a second-order finite-difference in time and an arbitrary high-order staggered-grid finite-difference scheme in space,the reverse extrapolation operator was obtained;the first-arrival travel time was computed by single-frequency full wave equation and was used as imaging condition for pre-stack reverse-time migration.Designed depression model and rift model verified the method.The numerical results indicate that the approach can image complex formation and remove low-frequency noises caused by reverse-time migration
高阶交错网格有限差分法; 地震波波动方程; 叠前逆时深度偏移; 初至走时; 成像条件;
high-order staggered-grid finite-ifference approach; seismic wave equation; pre-stack reverse-time depth migration; first-arrival travel time; imaging conditions;