多波波场数值模拟与叠后逆时偏移分析研究

发布时间：2018-01-15 02:23

本文关键词：多波波场数值模拟与叠后逆时偏移分析研究　出处：《成都理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：多波波场数值模拟和偏移成像一直是地球物理学领域中一个重要的研究方向,两者都是建立在弹性波波动方程的基础之上。弹性波波动方程可以很好地保留弹性波在介质中传播时的运动学、几何学和动力学特征,波场信息十分丰富有利于提高我们对地震勘探中地震波的分析和认识。同时也是因为波场信息丰富而复杂,所以在对多波多分量勘探中的多波信息进行有效识别时存在困难。文章中针对性地研究了波动方程数值模拟以及叠后逆时偏移成像的相关方法原理后,由浅入深地从本构方程、几何方程以及运动微分方程入手推导了不同介质中一阶应力---速度方程,并且给出了它们在时间上2阶空间上2N阶的交错网格差分格式。然后运用交错网格有限差分算法对其进行数值模拟,分析研究不同介质中地震波的多波信息。对于有限差分算法中引入的数值频散,文中在常规的通量校正(FCT)方法基础上加以改进,提出了改进后的通量校正(FCT)方法。在随后的模拟实例中证明改进后的FCT方法要比常规FCT方法在消除频散方面更加有效,能有效地改善数值模拟精度,同时也能更好地保持真实波场特性,将改进后的FCT方法运用到多波波场数值模拟和叠后逆时偏移中。叠后逆时偏移的基础是波动方程,文中首先介绍了叠后逆时偏移的方法原理,然后推导了双程波时间上4阶空间上2N阶的高阶有限差分格式,运用该差分格式实现叠后逆时偏移。最后,建立不同的速度模型加以验证该算法的正确性、成像精度以及分析速度误差对偏移成像效果的影响。
[Abstract]:Multi wave field numerical simulation and imaging has been an important research direction in the field of Geophysics, both of which are based on the elastic wave equation of elastic wave equation can well retain kinematic elastic wave propagation in the medium, geometry and dynamics characteristics of the wave field information is very rich to improve our knowledge of the seismic exploration seismic wave analysis and understanding. It is also because the wave field information rich and complex, so difficult to identify in the multi-component multi wave information in exploration. The article focuses on the numerical simulation of wave equation and related method of post stack reverse time migration imaging principle after the constitutive equation from the ground from the shallower to the deeper, geometric equation and differential equation deduced force - velocity equation of first order should be in different media, and give them At the time of the 2 order staggered grid space order 2N difference scheme. Then using staggered grid finite difference numerical simulation of the algorithm, analysis of multi wave information of seismic wave in different media. The finite difference frequency algorithm introduced in the conventional flux scattered, correction (FCT) method in this paper based on improved, improved flux correction (FCT) method. In the simulation example later in the proof of FCT improved method than the conventional FCT method to eliminate dispersion is more effective, it can effectively improve the accuracy of numerical simulation, but also can better maintain the characteristics of the real wave field, the use of FCT the improved method to multi wave field numerical simulation and post stack reverse time migration. Post stack reverse time migration is based on the wave equation, this paper firstly introduces the principle of the method of inverse migration after stack, then the time on the 4 order space is two-way wave The higher order finite difference scheme on 2N order is used to realize post stack reverse time migration. Finally, different velocity models are established to verify the correctness of the algorithm, the accuracy of imaging and the effect of velocity error on the migration effect.

【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P631.4

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