三维叠前深度偏移技术在千米桥潜山勘探中的应用与效果

Application of 3-D pre-stack depth migration in prospecting for Qianmiqiao buried hill and its effect.

三维叠前深度偏移技术是解决地下构造复杂和速度横向变化大的地震资料成像问题的理想技术 ,叠前深度偏移技术的关键在于深度域层速度模型的正确建立以及偏移成像效果的客观检验。本文应用 Geo Depth三维叠前深度偏移处理软件 ,对大港油田千米桥潜山的地震资料进行了三维叠前深度偏移处理 ,取得了良好的处理效果。其处理方法可归纳为以下几点 :1在时间偏移剖面上拾取速度层位 ,建立时间域地质模型 ;2用相干反演法与速度转换法相结合 ,逐层求取层速度 ,建立深度域层速度模型 ;3用剩余速度分析与层析成像法迭代修改、优化深度域层速度模型 ;4选用克希霍夫积分求和法来实现三维叠前深度偏移。

D pre stack depth migration is a ideal technique for solving the seismic data imaging problem in condition of complex subsurface structure and high lateral varying velocity.The key of the technique is correctly building velocity model in depth domain and objective judgingly migration imaging effect.Using 3 D pre stack depth migration processing software—GeoDepth,the paper conducts 3 D pre stack depth migration processing for seismic data in Qianmiqiao buried hill of Dagang Oilfield and adopted a good processing results. The processing method can be summed up as follows:①picking up velocity layer in time migrated section and building up geological model in time domain;②evaluating interval velocity layer by layer and building up interval velocity model in depth domain combining coherent inversion with velocity transformation;③interactively modifying and optimizing the velocity model in depth domain using residual velocity analysis and tomographic imag ing;④realizing 3 D prestack depth migration by selecting Kirchhoff integrating summation.