速度闭合差校正方法

A new method for velocity mis-tie correction.

由于我国西部特殊的地表条件 ,使相交测线处常出现速度不闭合现象 ,明显地降低了速度场的精度。本文在分析相交测线速度不闭合原因的基础上 ,考虑速度在纵向上可分为数段 ,而每一段内速度变化规律在测线交点处应是相同的 ,对于平均速度近似呈线性关系 ,故提出采用多段折线最优逼近平均速度的方法 ,每段对应一套地层 ,在每段内求出相应的时间闭合差 ,采用科学的方法进行校正 ,解决相交测线处速度闭合问题。实际应用结果表明 ,方法是有效的。

surface condition in West China causes excessive velocity mis-tie at intersecting point of seismic lines to greatly reduce the accuracy of velocity field. Authors analyse the reasons why there occurs velocity mis-tie at each intersecting point of seismic lines. In velocity analysis, a seismic velocity curve may be divided into several segments, and velocity variations of corresponding segments are same at intersecting point of lines. Average velocity is nearly linear, and it may be approximated to a broken line. Each segment of the broken line corresponds to a formation. The time mis-tie corresponding to each segment is estimated and used in correction to achieve the velocity closure. Real application proves the method effective.