摘要
混合法偏移是一种将有限差分偏移和频率波数域偏移相结合进行偏移的方法，它兼有两者的优点，即既能适应较大横向变速情况，又节省内存和运算量。本文利用平方根算子的最佳逼近，导出了混合法偏移的一种新算法，其运算交替用ω－x域中的有限差分法和f-k是域中的相移法来完成。同时，还提出了一种新的吸收边界条件，它通过在边界外附加一个很薄的具有强吸收作用的边界层，并与衰减型吸收边界条件相结合，有效地消除了边界反射。该方法既适用于规则区域，又适用于不规则区域，其离散方程具有统一形式，易于编程。较多的模型计算和实际资料试算表明，该方法是一种计算量适中、处理精度高、稳定性好、吸收效果明显的偏移方法。
The hybrid migration is a metfor that combines the finite-difference migration with thefrequency-wavenumber migration. It has advantages of these two migration methed simultanansly, i.e., it can not ony handle large lateral velocity variations, but also save computer run time and memories. In the paper a new algorithm for the hybrid migration is derived, which is based on an optimizedapprpaching to the square-root opertor. The migration is completed alternatively with the phare-shiftmethod in f-k doman and the finite-difference mehed in ω-x domain. Also, a new absorbing boundarycondittion is proposed. After adding a thin layer with strong absorbing ability along the boundary, andcombining it with the attenuative absorbing boundary condition, we find that boundary reflections can beavoided effectively. The absorbing condition is suitable to both regular area and irregular area and its discrete equation has a united form and can be programmed easily. The comutations of theoretical modelsand field data show that the depth migration method is stable, accurate and efficient.
出处
《石油物探》
EI
CSCD
北大核心
1999年第3期1-7,13,共8页
Geophysical Prospecting For Petroleum
基金
中国博士后科学基金
关键词
混合法
深度偏移
吸收边界条件
地震勘探
hybrid method, depth migration, finite-difference method, phase-shift method, absorbing boundary condition
