【作者】 郝奇；

【导师】 滕吉文； 何樵登；

【作者基本信息】 吉林大学 ， 地球探测与信息技术， 2010， 博士

【摘要】 结合最新的时距曲线公式和最新的参数化方法,给出了一种自动非双曲线速度分析方案,并将其分别应用到理论合成数据和野外实际数据中,并对处理结果进行了定性分析。推导了基于非双曲线旅行时公式做动校正的微分相似性层速度和层非椭圆率反演公式,并在反演方案中使用了三次样条插值预条件算子,给出了约束最优化反演的具体流程,并对理论合成数据进行处理及定性分析。提出了成层VTI介质的梯形块状建模思想,介绍了建模的具体实现过程,推导了倾斜界面情况下VTI介质中用慢度表示的Snell定律公式,给出反射波射线追踪的具体实现过程,并通过具体的模拟实验,分析了算法的精度和计算效率。推导了解结合正则化和预条件的混合l~1 /l~2范数反问题的反演公式,给出了解这种反问题的共轭梯度算法。推导了适合成层VTI介质中梯形块模型的反射波旅行时反演公式,以及射线旅行时关于模型参数参数的Frechet导数。结合射线追踪技术和正则化的混合l~1 /l~2范数反演方案,给出了一种反射波层析成像反演算法,对合成数据进行反演并对结果进行定性分析,取得较满意的结果。更多还原

【Abstract】 Firstly, we improved the approximate formula of the phase velocity for qP wave in VTI media proposed by Berryman(2009). By tracking in the current international advances about inhomogeneous viscoelastic waves in anisotropic media, we propose a new perturbation formulas for the phase velocity and the poloarization of inhomogeneous plane wave in dissipative anisotropic media, which are more accurate than that proposed by Cerveny. By numerical analysis and comparison with exact solutions and approximation solution, we found that the accuracy of the new formulas are much higher than that of the original one.Seismic velocity analysis in seismic data processing is a popular technology. We summarizes the approximate formula proposed by predecessors and compares their accuracy by numerical mdeling. We also find that the q1-q2 parameterizaton proposed by Abadd(2009) is the best one. In recent years with the development of an automatic non-hyperbolic velocity analysis techniques, Siliqi(2000) and Abadd introduce the idear of automatic nonhyperoblic velocity analysis. Their method can estimate the moveout velocity and the anellipticity accurately. We combine the latest formulas derived by Alexiso(2009) and the model parameterization of time-distance curves proposed by Abadd(2009), while using the latest technology and the popular Curvelet denoising techniques instead of the Kriging filtering mentioned in Alexiso(2009) and Siliqi(2001). In order to test the performance of this scheme, we applied it to the synthetic data and the field data with large offset, respectively. The final results shows it is satisfactory.Differential semblance velocity inversion is a technology to estimate the velocity from the the objective function of the differential semblance. In the chapter 4 of this thesis, according to the scheme given by Li, and Symes in 2007 for interval velocity inversion based on NMO correction using hyperbolic traveltime formula, we propose the idear of inversion of interval velocity and anellipticity based on NMO correction using the nonhyperbolic one. Through a series of complex mathematical derivation, we show the optimization problem for non-hyperbolic differential semblance inversion, and the derivative of the objective function function with respect to interval velocity and anellipticity. By combining the nonlinear conjugate gradient algorithm with the constrained optimaization frame, we prove the validity of the algorithm using the synthetic data.Seismic tomography based on ray is still an important research topic. In order to realize it for layered VTI media, we firstly need to achieve the parameterization of the underground model and ray tracing in this parameterized model. Many Geophysicsts have proposed so much parameterization methods for ray tracing, in which the simplest one is to sample the underground model by discrete rectangular blocks. The layered underground medium can also be divided into a series of small trapezoidal block. For more complex models, we can discretize it into a series of irregular blocks. In chapter 5 of this thesis, according to the trapezoidal block modeling for isotropic medium by Zelt in 1988, we proposed a new schemes for trapezoidal block modeling.for VTI medium The layered VTI media is divided into a series of trapezoidal blocks, in which each node owns a group of Thomsen parameters. In addition, we also derive the Snell’s law for the VTI medium with a tilted interface, which can be used to estimate the phase slowness for reflected or transmitted ray tracing from that of the incident ray. The single-layer model , multi-layered model , and topology multi-layered model is investigated by the proposed scheme, which prove the algorithm’s practicality.In addition to computing traveltime by ray tracing in seismic tomography, it is also necessary to calculate Frechet derivative of the raveltime of rays with respect to the model parameters and resolve the inverse problem. In the chapter 6 of this thesis, we discusses the mathematical theory of tomography inverse problem. Moreover, according to the travel perturbation formula proposed by Cerveny, we present the Frechet derivative of the ray traveltime with respect to the model parameters in the trapezoidal blocks. In solving the inverse problem of tomography, according to Bube’s mixed l~1/l~2norm inversion theory, we derived a series of regularized and preconditioned mixed l~1/l~2norm inversion method and gives the corresponding algorithm process. Finally, we show a numerical experiment of reflective tomography and compare the results for reflected qP-wave, reflected qPqSV-wave as well as the joint of reflected qP- and reflected qPqSV- wave.更多还原