摘要
提出一种三维叠后偏移的一步差分方法，称为因子分解法．差分格式是二阶精度的隐式格式，求解方法与通常一步差分偏移不同，不采用分步法交替求解。ｘ－ｙ方向的二维问题，而是采用因子分解法，将求解的差分方程分解为向前因子和向后因子，从而在一次扫描中同时完成ｘ－ｙ方向的正递归和反递归．为了抑制边界反射，采用了吸收边界条件，给出了理论合成记录和实际记录的偏移结果，数值试验表明该方法具有较好的精度和较高的计算效率．
A difference scheme and an algorithm for 3-D poststack migration are presented. The difference scheme proposed here is implicit and of second order.In order to restrain the reflection on the artificial boundaries, the absorbing boundary conditions are equiped. The algorithm of solving the linear algebraic equations obtained fromthe difference scheme of migration equation and boundary conditions is based on the factorization of the coefficient matrix. The first factor generated by the first order backward difference in both x and y directions is a lower triangular matrix consisting of four diagonal elements. The second generated by the forward difference is an upper triangular one consisting of also four diagonal elements. The algorithm consists in solving successively the linear systems with the lower and upper triangular matrices. In such way the forward and backward recurrences in both x and y directions are fulfilled simultaneously in one sweep. Numerical experiments with the synthetic and field data demonstrate the precision and efficiency of the proposed method.
出处
《地球物理学报》
SCIE
EI
CSCD
北大核心
1996年第3期382-391,共10页
Chinese Journal of Geophysics
基金
国家基础研究重大项目
关键词
三维叠后偏移
因子分解法
地球物理勘探
D poststack migration, One-pass finite-difference migration without fractional steps, Factorization method.
