复杂构造中的逆时偏移技术应用分析

基于射线理论积分法的叠前深度偏移技术，在复杂地质结构（如盐丘、逆掩带等）及速度横向剧烈变化的地区，由于成像条件受到限制，影响了对地下地质体的正确认识。理论分析波动理论的逆时偏移的成像原理及优缺点，并经过实际资料的试验，取得了较好的成像效果。为进一步提高该技术的适应性，选择了不同的地震资料进行试验，结果表明，逆时偏移是改善盐丘或逆掩推覆体下复杂构造成像的有效方法，在速度变化不大、波场不复杂的地区，虽然逆时偏移成像的质量改善不大，但可以有效地保持地震信号的振幅。

Analysis on Application of Reverse Time Migration to Complex Geologic Structures

Using the prestack depth migration technology based on integral method of ray theory to areas with complex geologic structures (e.g. salt dome, overthrust nappe, etc.) and severe lateral velocity variation tends to influencing exact recognition of underground geologic bodies due to seismic imaging condition restrictions. This paper analyzes the imaging theory and its merits of reverse time migration (RTM) based on theory of wave, and gets better imaging effects in practice. In order to increase the RTM adaptability, a variety of seismic data are selected to test. The result shows that RTM is an effective technology for improving the imaging of salt dome and structures under overthrust nappe. In areas with little change of velocity and uncomplicated wave field, using RTM can effectively maintain the amplitude of seismic reflection signals, although the imaging improvement obtained by RTM is not obvious