频率波数域共偏移距叠前时间偏移方法

Frequency-wavenumber constant-offset prestack time migration

1. 同济大学海洋与地球科学学院,上海200092;2. 中国石化胜利石油管理局物探研究院,山东东营257022

School of Marine Geology and Geophysical Science, Tongji University, Shanghai 200032, China

叠前时间偏移 (PSTM)是一种改善速度分析及叠加效果, 提高剖面成像质量的十分有用的工具。AVO分析前进行叠前时间偏移, 能够有效地改善AVO的分析效果。提出了一种 2D频率波数域共偏移距叠前时间偏移方法, 阐述了其基本原理, 并用数值计算验证了方法的有效性和实用性。该方法不仅能够对大倾角地层进行成像, 较好地保持振幅, 而且运算速度快。偏移后的道集可以用于偏移速度分析。

Prestack time migration (PSTM) is useful in imaging and velocity analysis.Amplitude-preserving prestack migration before amplitude versus offset (AVO) can improve the AVO analysis effectively. We present a 2D frequency-wavenumber constant-offset prestack time migration algorithm, which can not only make better imaging of reflectors with steep dips and preserve amplitudes correctly, but also has high computation efficiency. Velocity analysis is performed on common image point (CIP) gathers after migration.