波动方程法叠前深度偏移能够较为精确地对地质体成像, 然而波场外推的数据量过于巨大, 影响了计算的效率。面炮组合和控制照明结合的叠前深度偏移通过对震源波场的控制以及高效的面炮偏移能够得到高质量的成像结果。进行控制照明叠前深度偏移的关键是合成算子的选择, 笔者基于有限差分的走时计算方法合成了逆时聚焦算子, 基于该合成算子利用傅里叶有限差分法进行了聚焦点控制照明叠前深度偏移, 针对M armou si 模型的试算结果表明了该方法的有效性及其在提高计算效率方面的巨大优势。

Although prestack depth migration of shot records can make a high-quality image,it needs too much computation for wavefield extrapolation and lowers the efficiency of the computation.Prestack depth migration of areal shot records and controlled illumination can get high-quality images by source wavefield controlling and highly efficient areal shot records migration. How to calculate the synthesis operator is the key problem of controlled illumination prestack depth migration. In this paper the inverse time focusing operator is synthesized based on the travel time calculation method of finite difference approach, and with this synthesis operator the authors calculate the focusing point controlled llumination prestack depth migration using Fourier finite difference.The test results of Marmousi model show its effectiveness and the great advantage of improving computational efficiency.