速度层析成像正反演技术研究

利用层析成像的基本原理对地质异常体进行速度层析成像正、反演研究，计算结果可以确定出地质模型中速度异常体的大小、位置和慢度值等物性参数。首先通过建立正演模型，将含有异常体的模型区域剖分成规则的矩形网格，在区域两边的钻孔中分别安置发射和接受装置，采用多点发射、多点接收的方法获得已知地质条件下的每条速度射线的走时值，而后根据线性回归的原则对所得的时间数据加入20%的噪声，采用医学中成熟的ART算法进行模型的反演计算，计算表明反演结果与正演模型十分地逼近，计算精度和速度都能达到满意的效果。

THE FORWARD AND INVERSION TECHNOLOGY FOR VELOCITY TOMOGRAPHY

Using the equations and principles of the velocity tomography technology, the authors studied the forward and inversion method for the geological model. The results show that such parameters of the model as its shape, location and slowness can be accurately obtained. First of all, the forward model was set up, the field was divided into regular rectangle grids, and the transmitting and receiving devices were installed respectively on the left and right edges of the section. Within the continuous transmission and reception, each velocity radial time can be obtained on the model. Then 20% noise was added to the travel time, the model was rebuilt with the mature ART method, and the inversion was employed to the model. It is shown that the inversion result approximates to the forward model, and the calculation precision and velocity are satisfactory.