起伏地表波动方程波场延拓起始面研究

Study on starting datum of wave equation wave field continuation for rolling surfaces

（中国石油化工股份有限公司江汉油田分公司勘探开发研究院，湖北潜江433124）

Exploration and Development Institute of Jianghan Oilfield Company, SINOPEC, Qianjiang 433124, China

在起伏地表地区的资料处理中，无论是叠前正演模拟还是叠前深度偏移，常规单程波动方程波场延拓都是从整条测线的最高点开始的，而这种波场延拓大都以单炮形式进行。为此，提出了一种从单炮排列最高点开始的波场延拓方法,由于单炮排列只是整条测线的一小部分，因此单炮排列所在地表的最高点不一定是整条测线所在地表的最高点，故这两点之间的零振幅波场的延拓可以省略。理论模型和实际地震资料试处理表明：在相同精度情况下，与传统的总是从零深度开始的“逐步–累加”波动方程波场延拓方法比较，从单炮排列最高点开始的波场延拓方法计算量小，地表起伏高差越大，运算效率越高。

In data processing of rolling surface regions, whether the pre-stack forward modeling or the pre-stack depth migration is used, the conventional one-way wave equation wave field continuation starts from the peak of the whole seismic line, and most of the wave field continuation is in the form of single-shot. Therefore, a wave field continuation method starting from the peak of single-shot spread was proposed. Since single-shot spread is a part of the whole seismic line, the peak of the single-shot spread is not always the peak of the whole seismic line, the continuation of zero-amplitude wave field between the two points can be omitted. The testing results of theoretical model and actual seismic data shows that with the same precision, comparing with the “step by step summation” wave equation wave field continuation method (starting from zero depth), the wave continuation starting from the peak of single-shot spread has smaller calculated amount, the larger the difference of elevation is, the higher the computational efficiency is.