【摘要】 复杂山地地表高程变化剧烈,影响速度分析和速度建模,造成偏移归位不准确。为消除山地地震资料偏移处理因高程变化大引起成像聚焦变差的问题,有效避开低信噪比下的深度域速度建模,提出了一套基于起伏地表叠前时间偏移的处理流程,主要处理步骤包括成像基准面构建、基于成像基准面的速度模型更新和起伏地表叠前时间偏移。构建成像基准面的目的是使获得的速度模型与实际速度模型最大程度相吻合;基于成像基准面的速度模型更新能使速度模型更有效地收敛;还原实际炮、检点关系的起伏地表叠前时间偏移提高了时间偏移的聚焦能力。西部某山区实际资料的处理结果表明,采用该处理流程得到的剖面品质高、分辨率显著提升、断点清晰、断面刻画明显,为后续解释工作提供了很好的资料。更多还原

【Abstract】 In complex mountainous areas,the large variation of elevation has a bad effect on velocity analysis and model building and results in inaccurate migration.In order to remove the effects of poor imaging focusing and avoid building depth-domain velocity model under the low signal-to-noise ratio,a pre-stack time migration scheme for rugged topography was proposed.The main procedures of this scheme include imaging datum construction,velocity model update based on imaging datum and prestack time migration for rugged topography.The purpose of building image surface is trying to make the obtained velocity model coinciding with the actual velocity model.The convergence of velocity model benefits from the velocity model update based on imaging surface.Meanwhile,by using this scheme,the actual shot-receiver relationship can be obtained to improve focusing ability of time migration.The real data examples at mountainous area in Western China illustrate that high-quality sections were achieved with obviously-improved resolution,clear breakpoints and break sections,which provides good basic data for subsequent interpretation.更多还原