地质构造约束高斯束层析反演方法与应用

A method of geological structure constrained tomographic inversion based on Gaussian beam and its application

高斯束层析介于射线类层析和波动方程类层析之间,兼具了计算效率高和过程稳定的优势,是速度建模的一种重要手段。但是,常规高斯束层析灵敏度矩阵建立在射线的基础上,不能遍历整个模型,求解过程不收敛。为此,建立了高斯束层析反演的完整流程,给出了高斯束层析灵敏核函数的构建方法,并且为了使层析反演过程趋于稳定且快速收敛,提出了将地质构造反射界面的倾角场和反射点的位置信息融入高斯光滑矩阵对高斯束层析矩阵进行正则化的方法。理论模型和实际地震资料测试结果验证了方法的可行性和有效性。

Gaussian beam tomography is a compromise method between ray-based tomography and wave equation tomography, which has advantages of high computational efficiency and robust processing ability. However, the sensitivity matrix of the conven- tional Gaussian beam tomography is built on ray theory.It still cannot illuminate the whole model and the solver of Gaussian beam tomography maybe non-convergent.We have established a complete process of tomographic inversion based on Gaussian beam and proposed a construction method for sensitivity kernel of the Gaussian beam tomography.In order to guarantee stability, and accel- erate the convergence of tomographic inversion process, we proposed to merge the dip field of the reflection interface and the posi- tion information of the reflection point into Gaussian smoothing matrix, which is used for the regularization of Gaussian beam to- mographic matrix.From the tests of theoretical model and seismic field data, the geological structure constraints can not only re- duce the uncertainty of the inversion and make the inversion process stable, but also recover more geological details, thus verifying its feasibility and effectiveness.