基于保角变换的连续介质偏移成像

Migration of continuum modeling based on conformal transformation

用偏移成像方法对速度各向异性介质进行成像时,存在水平同相轴及大倾角界面畸变的缺陷.本文采用基于保角变换的偏移成像方法对畸变缺陷进行校正.首先,利用保角变换法可将不规则边界的单连通区域转变成规则边界的原理,将规则边界的连续介质场转变成不规则边界的均匀介质场,使该均匀介质场更适应现有Stolt等偏移方法对速度场的要求;其次,对改变了区域的模型地震记录进行常规的偏移成像处理;再利用推导出的反变换公式对成像结果进行反变换,得出模型的真实偏移成像结果.文章对合成模型进行了试算,并将试算结果与模型进行了比较.

In this article we studied the forward modeling of the medium which was continuous complex. In the first step, through using the formula of the conformal transformation, a continuous medium with regulation boundary in original area could be transformed to a homogeneous medium with anomalous boundary in complex area, so the new constant velocity field could be more adapt to the current Stolt migration＇s conditions. In the second step, the new model would be migrated by normal migration method. In the last step, the migration result in original area could be obtained by using inverse transform formula. The performance of the method is demonstrated on simple synthetic model. The migration result using this method is then compared with the model.