“绕射积分偏移”的成象原理及提高其偏移剖面质量的探讨

“绕射积分偏移”的过程一直都是用绕射波收敛理论来描述的.但是这个理论不能解释为什么经过“绕射积分偏移”的剖面会有信噪比降低和弧形干扰的现象.在这时,我们用一个简单的数学模型,并理想化了一些条件,弄清了“绕射积分偏移”成像的真正原理.我们发现在任一CDP点下面的反射界面点的位置应与某一双曲线的顶点时间相当,这个双曲线正好处在与相应的反射t_0剖面上各道波至所形成的直线相切的位置上.在此结果的基础上,本文提出了减少干扰和改善剖面质量的有效措施.我们希望它能尽早为实际工作所采用.另外,本文也对目前流行的几种类型的所谓“克希霍夫积分偏移”进行评述并指出它们的缺点.

A DISCUSSION ON THE IMAGINARY PRINCIPLE OF "DIFFRATED INTEGRATED MIGRATION" AND THE IMPROVEMENT OF THE MIGRATION SECTION

So far, the theory of "Convergence of the Defraction Wave" has been used to describe the process of "Defraction Integral Migration". Unfortunately such a theory has failed to explain how the ratio of signal to noise is reduced after migration and where the so-called "Arc-like" interference comes from on the seismic section migrated.In this paper, we have managed to clarify the actural imaging principle of "Defraction Integral Migration" by using a simple rnathematic model with some idealized, conditions As a result, it has been discovered that the position of a reflection horizon vertically beneath a CDP (i. e. the vertical depth of the reflection horizon) should correspond to the apex time of a hyperbola which is just of tangency with the line formed by the corresponding reflected arrivals on the t0 section.Based on such a result, an effective measure for minimizing the interferences and consequently improving the quality of the migrated section has been put forward in this paper. We are looking foard to having it come into use in the nearest future.In addition, some types of the so-called "Kercheholf Integral Migration method" currently utilized in seimic interpretation were appraised. Naturally, their defects were pointed out as well.