浅层速度横向变化对深层速度分析的影响

通常进行速度分析时假设地层没有速度横向变化，但是实际情况并非如此。本文采用射线追踪方法计算了几种浅部地层速度横向变化模型的时距曲线。速度分析的结果表明，浅层速度横向变化会对深层的速度分析结果有不可忽视的影响，产生与横向均匀介质完全不同的现象。由此可见，在利用速度分析结果建立速度模型时，必须考虑这些效应。

The Influence of shallow lateral velocity variation upon deep velocity analysis

The assumption that there is no lateral velocity variation in a stratum is usually made in velocity analysis. However, this assumption does not coincide with real situations at all. The time-distance curves of several shallow lateral velocity variation models are estimated by using ray tracing method. Velocity analysis result shows that shallow lateral velocity variation causes noticeable influence upon deep velocity analysis result, which thus brings an effect being absolutely different from that in laterally uniform medium. It can be seen from this that the effect must be considered in velocity model construction using velocity analysis result.