大地电磁测深与地震初至波走时交叉梯度反演

在地球物理勘探过程中,观测数据有限且存在误差,导致反演结果存在非唯一解。为了解决非唯一性问题,笔者研究了交叉梯度数学理论,实现了用交叉梯度约束2D 大地电磁和地震初至波走时的联合反演,并建立了2个模型。通过各自模型实验和不同模型间的对比,证明了交叉梯度联合反演比单独反演修复几何形态和物性参数的效果好,且交叉梯度与岩石物性无关;利用得到的交叉梯度图进一步证明了联合反演模型相似度高,也从交叉绘图中得到联合反演的物性关系更好的结论,反向证明了联合反演的正确性。

Joint Inversion of Magnetotelluric and First-Arrival Wave Seismic Traveltime with Cross-Gradient Constraints

In the process of geophysical exploration,observation data are limited and errors exist, leading to the presence of non-unique inversion results.In order to solve the problem of non-uniqueness, the authors study the mathematical theory of cross-gradient,and achieve the joint inversion of 2D magnetotelluric and first-arrival wave seismic traveltime with cross-gradient.At the same time,we establish two models.Through test of each model and comparison between the two models,it is proven not only that the result of the cross-gradient joint inversion is better than the single inversion in remediation on geometry and physical property parameters, but also that the cross-gradient is independent from the petro-physical properties.Further,the cross-gradient figure evidences the high similarity of the joint inversion models,and the cross-plot of joint inversion presents a better correlation with physical properties.These,in turn,prove the validity of the joint inversion.