角度域叠前时间偏移:非均匀介质中的单程波方法

摘要

Based on the one-way wave equation, we develop the schemes to calculate the travel time, angle between incident and reflection waves, and amplitudes for prestack time migration in angle-domain. A prestack time migration method and the work-flow that can generate imaging gathers in angle-domain are proposed. We do a numerical analysis of the effects of velocity gradient on travel time, angles, and amplitudes, and then propose angle and amplitude calculation methods that can treat media heterogeneity better. Numerical tests of model and real data demonstrate the effectiveness of the scheme.%从单程波方程出发,推导出角度域叠前时间偏移的走时、入射波与反射波夹角、成像幅值计算方法；构建了可直接生成角度域成像道集的叠前时间偏移方法与偏移流程.文中定量分析了速度梯度对走时、角度、幅值的影响,给出了可更好考虑介质非均匀性的角度、幅值计算方法.理论模型以及实际数据验证了本文方法的有效性.