网格层析速度反演技术在齐古背斜叠前深度偏移中的应用

Mesh tomographic velocity inversion for the prestack depth migration of the Qigu anticline

针对准噶尔盆地南缘齐古背斜主体构造复杂、地层倾角较大、基于层位的速度建模方法在该区精度较低的难点,采用网格层析速度反演方法,建立工区准确的速度模型。该方法通过共成像点道集上的残余深度差全局更新速度模型,更适应于山前带深度域模型的迭代更新。应用结果表明,该技术可以提高速度模型精度,改善复杂构造区地震成像效果,验证了网格层析速度反演在复杂构造区叠前深度偏移中的有效性和实用性。

In the southern margin of the Junggar Basin,the main structure of Qigu anticline is complex with large dip.The velocity modeling method based on the horizon suffers low accuracy in the area.To solve the problem,we use the mesh tomographic velocity inversion provided by GeoEast.This approach can update velocity model with residual moveout of common imaging point gathers on the global.And the more important,it can iteratively update the depth domain model for the pediment.The application example shows that the approach can improve both the velocity model accuracy and the seismic imaging accuracy in complex structure areas.Our application proves the effectiveness and practicability of the mesh tomographic velocity inversion in complex structure area.