关键词: 共偏移距叠加, 近地表异常, 长波长静校正, 反射时间差

Abstract: Model method, reflection method and tomographic method are common datum static correction methods at the present time. Summarization and analysis of the fundamental principles of various static correction methods and applicable conditions indicate the precondition that all of them are based on the surface consistency and vertical penetration of near surface by seismic reflection. However, under the complicated geological conditions, particularly in the region where static correction of long wavelength exists, it is difficult to meet the assumption of surface consistency. In fact, when the abnormal zone of velocity exists, seismic waves seldom propagate vertically. The distance for the statics and rays to go through near surface is closely related to the velocity. In reflection seismic exploration, far and near offset reflection waves can generate different statics at the time of penetrating near surface. If this phenomenon is used as a principle for to judge the abnormality of target formation as the abnormality of near surface, the problem of long wavelength static correction in the abnormal zone of surface can be solved. This article elaborates on this method, which has desirably solved the static correction problem caused by the near surface abnormality since it was used for production.