叠前深度成像技术分析及应用

本文从原理和技术两个方面论述了地震偏移技术的发展，分析了各种偏移技术的差异，以及成像条件的三种表述。在阐述叠前深度成像速度建模技术基础上，提出了速度建模应遵循的一些基本原则：①要选择连续性好的同相轴，层厚不能太薄，邻层的层速度变化应大于10％；②构造平缓的部位可适当减少目标线解释，构造复杂时可加密目标线解释；③应根据常规偏移剖面拾取的时间层位进行层速度修改，力求在纵、横两方向上保持层速度平滑，使CRP道集拉平。通过叠前深度成像技术在海拉尔应用的实例，表明叠前深度成像效果要明显优于常规叠后偏移效果。

Analysis and Application of Prestack Depth Imaging Technique

The paper expounded the development of seismic migration technique from two aspects : principle and technique,analyzed the differences of different migration techniques and presented three expres sions of imaging conditions. On the basis of expounding model-building technique of prestack depth imaging velocity,the paper presented follow ing basic principles that the velocity model building should follow :(1)it should choose the events having good continuity, the thickness of beds should not be too thin and differential interval velocities of ad jacent layers should greater than 10%; (2)it can ad-equately reduce the interpretation of target lines in gentle parts of structures and increase the interpretation of target lines when the structures are complex ;(3)it should make modification of interval velocities according to picked time horizons in ordinary migrated sections, making efforts to keep smooth variation of interval velocities both in vertical and in lateral directions and align the CRP gathers. It was showed by the applied cases of prestack depth imaging technique in Hailar area that the effects of prestack imaging technique are significantly superior to that of poststack migra- tion.