全方位倾角道集反射波场分离及成像技术的应用

The application of reflection wave field separation and imaging techniques for full azimuth dip gathers

随着“两宽一高”采集、处理技术的普及,局部角度域叠前深度偏移产生的全方位倾角道集中保留了反射波、绕射波、回折波等波场的倾角和方位角信息,且在全方位倾角道集中不同地震波场更易于识别和区分,为叠前反射波场分离和成像提供了基础。根据理论模型正演的全方位倾角道集中反射波能量明显强于其他波场能量的特性,以及反射波与绕射波等其他波场走时上的特征差异,制定了从实际数据的叠前全方位倾角道集中分离反射波场的流程,将波场分离后的叠前全方位倾角道集叠加成像,提高了目标区的成像质量。将该技术应用于哈萨克斯坦M工区三维实际数据,结果表明,应用全方位倾角道集叠前反射波场分离和成像技术之后,探区西部破碎带的断层成像更清晰,明显提高了成像质量,为该区精细构造解释及地质研究奠定了基础。

With the popularization of“wide azimuth,wide frequency band and high density”seismic acquisition and processing technique,rich dip and azimuth information about wave fields such as reflection waves,diffraction waves,and diving waves is retained in full-azimuth dip gathers generated by pre-stack depth migration of local angle domain.The different seismic wave fields are easier to identify and distinguish in the full-azimuth dip gathers,laying a foundation for the pre-stack reflection wave field separation and imaging.In the full-azimuth dip gather modeled by the theoretical model,the reflection energy is significantly stronger than the energy of other wave fields,and there are kinematic differences between reflection waves and diffraction waves.Based on this,the processing workflow of reflection wave separation from actual full-azimuth dip gathers is formulated.Then,the pre-stack full-azimuth dip gather after wave field separation is superimposed to improve the imaging quality of the target area by reflection stacking and imaging.The method has been applied to 3D actual data in Kazakhstan,and the results show that the fault imaging of the western fractured zone in the exploration area is clearer to notably improve the imaging quality by the proposed technology,which lays a foundation for fine structure interpretation and geological research in this area.