一种有效的三维PS波保幅叠前时间偏移方法

基于加权绕射叠加的偏移和反演方法都是以Born近似或者Kirchhoff近似理论为基础,在绕射叠加算法中引入振幅信息,通过振幅加权函数实现地震数据的Kirchhoff积分法保幅叠前偏移。采用不同的近似理论可以推导出不同形式的振幅加权函数,用于时间域和深度域纵波(PP)和转换波(PS)资料的处理。通过以Bleistein和Schleicher为代表的两种类型振幅加权函数系数分布规律的研究，以及保幅偏移成像道集(CIP)和保幅叠前时间偏移(PSTM)剖面的对比分析,确定了一种相对有效的适合三维PS波各向异性PSTM的振幅加权函数,将其应用于西部A,B区块三维PS波保幅各向异性PSTM处理，取得了一定效果。

All kinds of weighted diffraction stack of migration/inversion methods are based on Born approximation or Kirchhoff approximation theory.The amplitude information is brought in the diffraction stack algorithm,the true-amplitude prestack migration for Kirchhoff integral algorithm is implemented with the amplitude weighted function.By different approximation theories,the different forms of the amplitude weighted function can be deduced for processing pressure wave(PP) and converted wave(PS) data in the time domain and depth domain.Through the research of the coefficient distributions from two types of amplitude weighted

functions proposed by Bleistein and Schleicher respectively,and comparison of the imaging gathers(CIP) after true-amplitude migration and imaging sections after true-amplitude prestack time migration(PSTM),an amplitude weighted function that is relatively effective for 3D PS-wave anisotropic PSTM is determined,of which the application proves the effectiveness for actual 3D3C data processing.