带正则化校正的TTI介质qP波方程及其逆时偏移方法和应用

发布时间：2018-05-05 15:15

  本文选题：TTI介质 + 各向异性　； 参考：《地球物理学报》2016年03期

【摘要】：各向异性研究对地下介质精确成像有着重要的意义,在当前计算机硬件迅速发展及宽方位地震数据采集日益普遍的情况下,成像必须考虑介质的各向异性.逆时偏移是基于双程波动方程的较为精确的数值解的成像方法,所以相对于其他地震成像方法,它具有很大的优势,譬如不受反射界面的倾角限制、偏移速度结构合适时能够使回转波及多次波正确成像.在各向同性介质中,可使用标量波方程来模拟波场.而在各向异性介质中,P波和SV波是相互耦合的,即不存在单纯的标量波传播,通常利用能代表耦合波场中P波分量运动学特征的拟声波(qP波)进行偏移成像.本文中,我们推导出了TTI介质下qP波控制方程.该方程可采用显式有限差分格式进行求解.通过声学近似,若沿对称轴方向的剪切波速度为零,对于对称轴方向不变且ε≥δ的模型来说,可得到稳定的数值解.但对于TTI介质来说,由于沿对称轴方向各向异性参数是变化的,声学近似会引起波场传播及数值计算的不稳定.因此,我们提出了正则化有限横波的方法,很好地解决了这一问题.最后,给出了Foothill模型的测试结果及某探区实际资料试算结果,展示了采用这个方程进行复杂TTI模型正演和高质量逆时偏移成像结果,证实了该方法的正确性和实际资料应用中的有效性.
[Abstract]:The study of anisotropy plays an important role in accurate imaging of underground media. With the rapid development of computer hardware and the increasing popularity of seismic data acquisition in wide azimuth, anisotropy of medium must be considered in imaging. Inverse time migration is an imaging method based on a more accurate numerical solution of two-way wave equation, so it has great advantages over other seismic imaging methods, for example, it is not restricted by the dip angle of the reflection interface. When the migration velocity structure is suitable, the rotation and multiple waves can be correctly imaged. Scalar wave equation can be used to simulate the wave field in isotropic media. However, in anisotropic media, the P wave and SV wave are coupled, that is, there is no simple scalar wave propagation, and usually the pseudo acoustic wave QP, which can represent the kinematic characteristics of the P wave component in the coupled wave field, is used for migration imaging. In this paper, we derive the QP wave control equation in TTI medium. The equation can be solved by explicit finite difference scheme. By acoustic approximation, if the velocity of shear wave along the symmetry axis is zero, the stable numerical solution can be obtained for the model with constant symmetry axis and 蔚 鈮，

本文编号：1848188