TTI介质快速扫描法计算qP走时及微震震源和各向异性参数联合反演

发布时间：2018-03-19 04:19

本文选题：TTI　切入点：反演　出处：《中国科学技术大学》2016年博士论文　论文类型：学位论文

【摘要】：各向异性速度模型在地球物理中得到越来越多的关注,尤其是具有代表性的垂向对称轴薄层各向同性的VTI模型和倾斜对称轴的TTI模型。在VTI和TTI模型中,相速度和群速度都随着角度而变化,对于准确快速计算走时有很大的挑战,本文主要从以下两个方面做出了努力:1.2D和3D的快速扫描法计算TTI介质中qP波的走时。传统计算各向同性介质中P波走时的方法在扩展到VTI和TTI时候,会面临很大的挑战:1)相速度和群速度的不一致性会导致传统方法破坏时间因果性条件;2)当介质变得复杂以后,如何保证得到的走时是时间最小的。我们提出的新型快速扫描法(FSM)通过解析的求解一元四次方程(程函方程),得到可能的走时信息,再通过验证因果性条件来判断走时是否满足因果关系。如此我们很好的解决了第一个问题,再配合Gauss-Seidel迭代来更新走时,如果迭代次数充足,走时就趋于稳定,这保证了走时是最小的。2.在层状VTI介质中,联合反演微震震源位置和各向异性参数。在微震监测中,得到可靠的速度模型和震源位置有利于扩大油气产量。本文提出一种联合微震震源位置和各向异性参数的反演方法。在计算走时方面,我们用了水平慢度打靶法,Snell公式隐式地包含在打靶过程中。同时走时对Thomsen参数的导数,也是基于慢度求的,这使得推导过程简单明了。本文通过模拟数据对联合反演的可靠性进行了研究,并将此方法应用到了实际的地震资料中。
[Abstract]:The anisotropic velocity model has gained more and more attention in geophysics, especially the representative VTI model vertical axis of symmetry thin isotropic and tilted symmetry TTI model. In the VTI and TTI model, phase velocity and group velocity changes with the angle, for rapid and accurate calculation time greatly the challenge, this paper mainly from the following two aspects: to make travel time calculation of qP wave in TTI media 1.2D fast scanning method and 3D method. The traditional calculation of travel time of P wave in isotropic media to VTI and TTI in the expansion, will face a lot of challenges: 1) the inconsistency of phase velocity and group velocity the traditional method will lead to the failure time causality condition; 2) when the medium becomes complicated, how to guarantee the travel time is the minimum time. We propose a new fast scanning method (FSM) by analyzing the solving equation of four degree ( Eikonal equation), obtain the possible traveltime information, then verify the causality condition to judge whether meet the causal relationship. So when we solve the first problem, coupled with the Gauss-Seidel iteration to update time, if the number of iterations is sufficient, as it tends to be stable, to ensure that the travel time is the smallest.2. in layer in VTI medium, the joint inversion of seismic source location and anisotropic parameters. In microseismic monitoring, velocity model and reliable source location is conducive to the expansion of oil and gas production. This paper proposes a joint inversion method of seismic source location and anisotropic parameters. In the calculation of travel time, we use the slowness shooting method. The Snell formula is implicitly included in the targeting process. At the same time as the parameters of Thomsen derivative, is also based on slowness request, which makes the derivation process is simple. This paper intends to through the data model The reliability of the joint inversion is studied, and this method is applied to the actual seismic data.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P631.4

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