三角网格剖分下速度与反射界面的同时反演

发布时间：2018-03-04 14:47

本文选题：三角网格单元参数化　切入点：多震相射线追踪　出处：《地球物理学进展》2017年03期 　论文类型：期刊论文

【摘要】：为了解决复杂速度模型中的走时正、反演问题,例如:含不规则起伏地表、不规则地下波阻抗界面、以及不规则速度异常体的复杂地学模型,本文采用三角网格单元模型参数化下的分区多步改进型最短路径算法,实现了多震相地震射线的追踪计算,结合共轭梯度法求解带约束的阻尼最小二乘反演问题,实现了多震相走时联合同时反演成像的方法技术.当界面起伏较大时出现散射,从而造成散射点所在区域射线密度过密,导致该区域内速度和界面的过度更新.为了克服上述问题,我们在同时反演中引入了射线密度的概念,从而有效地解决了上述过度更新问题.数值模拟实验表明:采用三角网格单元进行模型参数化,可保证在复杂模型中的正演计算具有较高的计算精度;同时反演中可以准确地刻画不规则异常体和不规则反射界面.因此,本文提出的走时成像方法技术具有较广的实用价值.
[Abstract]:In order to solve the traveling time positive problem in complex velocity model, inversion problems such as irregular undulating surface, irregular underground wave impedance interface, and complex geophysical model of irregular velocity anomaly, In this paper, the multi-step improved shortest path algorithm based on the parameterized triangular grid element model is used to realize the multi-phase seismic ray tracing calculation, and the conjugate gradient method is used to solve the constrained least square inversion problem. The technique of simultaneous inversion imaging of multi-phase walking time is realized. The scattering occurs when the interface fluctuates greatly, which results in the density of the scattering point being too dense in the region where the scattering point is located. In order to overcome the above problems, we introduced the concept of ray density in simultaneous inversion. The numerical simulation results show that the model parameterization with triangular mesh element can guarantee the accuracy of forward calculation in complex model. At the same time, the irregular bodies and the irregular reflection interfaces can be accurately described in the inversion. Therefore, the travel-time imaging method proposed in this paper has a wide range of practical value.
【作者单位】：长安大学地质工程与测绘学院地球物理系;新疆财经大学网络与实验教学中心;长安大学计算地球物理研究所;
【分类号】：P631.4

【相似文献】