起伏地表下合成震源记录剩余偏移速度分析
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摘要
提出一种起伏地表下新的剩余偏移速度分析方法.应用控制照明技术,克服了由于在起伏地表上合成的震源波场不是平面波震源波场而不能应用剩余速度校正公式的障碍,使得射线参数在偏移和速度分析过程中保持一致,且避免了因横向变速而导致的平面波震源波场在传播过程中的畸变.利用改进的合成震源记录叠前深度偏移,直接从起伏地表延拓波场和成像,偏移前无需对地震数据做静校正或重定基准面.合成数据试算表明该方法是有效和实用的.
A new residual migration velocity analysis(RMVA) method with irregular surface is proposed.Using the controlled illumination technique,the difficulty that the velocity correction formulae can not be used because the source wave field synthesized at the irregular surface is not the plane wave source wave field,is overcome which keeps the consistent ray parameters in both migration and velocity analysis,and the severe distortion of the plane wave source wave field caused by the lateral velocity variation during extrapolation is avoided.The improved synthetic source record prestack depth migration(PSDM) method is used to extrapolate wave field and image the data directly from the irregular surface without any datuming or elevation static corrections before applying the migration.The results of synthetic data test demonstrate that the method is valid and practical.
A new residual migration velocity analysis(RMVA) method with irregular surface is proposed.Using the controlled illumination technique,the difficulty that the velocity correction formulae can not be used because the source wave field synthesized at the irregular surface is not the plane wave source wave field,is overcome which keeps the consistent ray parameters in both migration and velocity analysis,and the severe distortion of the plane wave source wave field caused by the lateral velocity variation during extrapolation is avoided.The improved synthetic source record prestack depth migration(PSDM) method is used to extrapolate wave field and image the data directly from the irregular surface without any datuming or elevation static corrections before applying the migration.The results of synthetic data test demonstrate that the method is valid and practical.
引文
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[5]RIETVELD W E A,BERKHOUT A J.Prestackdepth migration by means of controlled illumination[J].Geophysics,1994,59(5):801-809
[2]YAHYA K A.Velocity analysis by iterative profilemigration[J].Geophysics,1989,54(6):718-729
[3]JIAO J,STOFFA P L,SEN M K,et al.Residualmigration-velocity analysis in the plane-wave domain[J].Geophysics,2002,67(4):1258-1269
[4]RESHEF M.Depth migration from irregular surfaceswith depth extrapolation methods[J].Geophysics,1991,56(1):119-122
[5]RIETVELD W E A,BERKHOUT A J.Prestackdepth migration by means of controlled illumination[J].Geophysics,1994,59(5):801-809
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