真地表速度建模技术在复杂山地地震资料成像中的应用

Application of True Surface Velocity Modeling Technology to Imaging of Seismic Data in Complex Mountainous Areas

传统的叠前深度偏移成像技术将偏移成像和静校正问题分开处理,在复杂山地资料处理中,由于地表条件复杂、近地表横向速度变化剧烈、高速层出露等问题,基于地表一致性假设的静校正处理会引起波场畸变,导致旅行时计算误差较大,影响深度偏移成像效果。因此,提出了一种基于真地表偏移面的全深度建模与成像技术方案,从地表高程面开始速度建模,计算旅行时,将静校正问题隐含在偏移成像过程中,在复杂山地资料处理中取得了较好的应用效果。

Conventional pre-stack depth migration imaging techniques separate the migration imaging and static correction processing.In the processing of seismic data from complex mountainous areas,due to the factors such as complex surface condition,drastic lateral veloci-ty variation near the surface,and exposure of high-velocity interval,the static correction based on the assumption of surface consistency may cause wave field distortion.This distortion leads to big errors in calculation of travel time,affecting the effects of depth migration imag-ing.To solve this problem,a full-depth modeling and imaging technique based on true surface migration was proposed.This technique starts with velocity modeling and travel time calculation from the surface elevation,and addresses static correction implicitly in the migra-tion imaging process.It has been satisfactorily applied in the processing of complex mountainous data.