剖面三维地质建模及高斯射线束正演

3-D geological modeling based on a section and Gaussian beam forward modeling

提出了一种利用二维地质剖面构建三维块状地质模型的方法。该方法以用户编辑的二维地质剖面为输入,寻找地质块体的拓扑关系,自动构建以地质块体为单元的块状三维地质模型。在三维块状模型的基础上,研究了三维高斯射线束正演方法。这是一种快速的地震记录合成方法,它将波动方程和射线理论紧密结合起来,通过运动学射线追踪获取射线轨迹,通过动力学追踪来获取中心射线附近的高频能量分布,因而既能反映波的运动学特征,又能表现波的动力学特点,并且具有运算速度快、精度高等优点。

The ray method plays a vital role in seismic exploration. The 3-D block geological model is the base of the ray numerical modeling. However the 3-D geological modeling, especially the complex model structure usually is quite difficult. This paper proposes an algorithm to use two-dimensional geological cross section to construct the three dimensional geological model. The algorithm has effectively solved the complex geological modeling problem. Based on the first hand information about 2-D geological cross section edited by users, the method researches the topology of geological blocks and automatically structures model on 3-D geological blocks. With the 3-D block geological model, the authors deeply research the numerical modeling method of Gaussian Beam. Gaussian beam method is a fast method of seismic wave field modeling. The seismic wave field obtained by this method has wave properties in both kinematics and high-frequency dynamic. By merging wave equation with the ray theory, the method obtains ray tracks by the kinematical ray tracing and distribution of high-frequency by the dynamic ray tracing. As a result, it has the dynamic and geometric characters and costs little calculation time, and shows good precision.