基于双程波动方程的多次波照明分析方法研究

Study of multiples illumination analysis method based on two-way wave equation

地震照明分析是地震数据采集和实际资料处理解释中的一种辅助手段,指在给定地下地质构造时,采用数值模拟的方法模拟出地震波在地下介质中的能量分布形态.自由表面相关多次波是海上地震数据中重要的波场信息,传统地震数据处理方法一直都将其视为干扰信息而进行去除,错失了很多有意义的构造信息.本文采用基于时间域有限差分法的双程波动方程进行波场数值模拟,将多次波能量考虑到波场照明中,通过单一透镜盐体模型试算表明,与传统一次波照明相比,多次波照明方法的波场信息更丰富、盐下构造照明更清晰、照明阴影区域更小.将多次波照明分析应用到Pluto速度模型,对比分析可以看出多次波照明分析方法更能适应复杂地质构造目标.通过多次波照明分析方法,我们能够对复杂地质构造的采集系统进行评价和优化,并预测地震偏移成像的质量.

Seismic illumination analysis is an auxiliary means of seismic data acquisition and actual data processing. Given the underground geological structure,seismic illumination analysis can accurately simulate the energy distribution of seismic wave in underground medium by numerical simulation method. Surface related multiple is an important part of marine seismic data which has always been regarded as noise in traditional seismic exploration and thus be removed, resulting in lots of available structure information lost. In this paper,we conduct wave-field numerical simulation by two-way wave equation based on time-domain finite difference method to introduce multiples into wave-field illumination The test of single lens-shaped salt shows that multiples illumination has richer wave-field information, clearer subsalt structure illumination and smaller shadow area compared to traditional illumination method. The application of Pluto model shows that multiples illumination analysis can better adapt to complex geological structure. Multiples illumination analysis can evaluate and optimize the acquisition system of complex geological structure and predict the seismic imaging quality.