摘要
地震反射系数的幅值与相位是地震反射波的重要特征,对地震资料反演起着重要作用。利用自由界面上SV波入射的反射系数公式,通过建立9个不同泊松比的介质模型,绘制了反射SV波与转换P波反射系数的振幅、相位随入射角及泊松比的变化曲线,分析了不同泊松比介质的反射系数随入射角变化的规律,特别关注临界角附近的突变特征。通过对比分析发现:在临界角附近,对于P波反射系数的突变值,大泊松比(0.3~0.5)和小泊松比(0~0.3)介质存在较大差异。随着采样点数的增加,能更准确观测到SV波反射系数曲线在临界角前的极小点,进而充分认识SV波的全波型转换。研究结果对于深入认识地震波传播特征以及实施广角地震勘探或多波地震勘探具有较大实际意义。
The amplitude and phase of the seismic reflection coefficient are important characteristics of seismic reflection waves and play an important role in seismic data inversion.In this paper,by using the reflection coefficient formula of the incident SV wave on the free interface and establishing nine medium models with different Poisson′s ratios,the amplitude and phase of the reflection coefficient of the reflected SV wave and the converted P wave are plotted as a function of the incident angle and Poisson′s ratio.The reflection coefficient of different Poisson′s ratio media with the incident angle is analyzed,and the characteristics of sudden changes near the critical angle are paid special attention to.Through the comparative analysis,it can be seen that near the critical angle,for the sudden change of the P wave reflection coefficient,there is a big difference between the medium with a large Poisson′s ratio(0.3~0.5)and a medium with a small Poisson′s ratio(0~0.3).With the increase of the sampling points,the minimum point of the SV wave reflection coefficient curve before the critical angle can be observed more accurately,and then the full-wave mode conversion of the SV wave can be fully understand.It is of great practical significance to study the variation characteristics of the reflection coefficient near the critical angle for in-depth understanding of the characteristics of seismic wave propagation,as well as to implement wide-angle seismic exploration or multi-wave seismic exploration.
作者
程雯泽
尹成
王毓玮
CHENG Wenze;YIN Cheng;WANG Yuwei(School of Earth Science and Technology, Southwest Petroleum University, Chengdu,Sichuang 610500, China)
出处
《石油管材与仪器》
2022年第3期66-70,76,共6页
Petroleum Tubular Goods & Instruments
基金
2021年四川省大学生创新训练计划项目“自由界面上SV波入射的反射特征研究”(编号:S202110615176)。
关键词
自由界面
入射SV波
反射系数
入射角
泊松比
临界角
free interface
incident SV wave
reflection coefficient
incident angle
Poisson′s ratio
critical angle
