地震波场正演模拟中的有限单元方法

本文介绍了地震波场正演模拟中的有限单元方法。首先从粘弹性波动理论出发,推导了满足粘弹性介质的有限元方程,其次用不含阻尼矩阵的有限元方程模拟了地震记录。地表实例是自由界面的瑞雷面波。VSP记录有水平层、倾斜层;有零井源距和非零井源距;有线状和对称震源。 在程序中采用了超压缩存贮和分块计算措施,对降低有限元法要求计算机内存和运算速度的苛刻条件上做了有益的尝试。

THE FINITEELEMENT METHOD IN FORWARD PROBLEM OF VSP

This paper mainly introdes the finite element method in forward problem of VSP.It can be divided into two parts.First, from the theory of viscoelastic wave using the principle of calculus of variations, a new method for constructing the damping matrix is presented. The useful inquiry and study of forward problem in viscoelatic medium are by means of finite element method.In the second part, using the finite element method without the damping matrix, the model seismic records and VSP records in well are calculated. The typical modeling case is REYLEIGH surface wave on the earth surface.The VSP result is the same as the theoretical analysis.The VSP recirds of the constructure of horizontal layer, slope layer and ect are made. The zero-offset and nonzero-offset experiment, shallow shot point shotand nonsymmetrica shot are used in calcula-ting the VSP records.The super-compress storage, seperata block some messure are used in computing.The useful attepts are made for reducing the harsh conditions of storage and speed for computer of the finite element method.