Offset and angle-domain common image-point gathers for shot-profile migration
Offset and angle-domain common image-point gathers for shot-profile migration
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DOI：
10.1190/1.1484531
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发表时间：
2002-05
期刊：
影响因子：
3.3
通讯作者：
J. Rickett;P. Sava
中科院分区：
文献类型：
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作者：
J. Rickett;P. Sava
向下延拓炮点剖面叠前深度偏移是一种实用的成像算法，特别适用于稀疏炮点宽方位角观测系统。炮检距是下传波场和上传波场之间的位移，炮检距偏移可以提取炮检距域共像点道集。偏移域道集然后可以利用最初为炮检偏移引入的径向道映射变换到角度域。该过程的计算影响包括多偏移距成像的额外成本和从炮检检波器到中点偏移距坐标的隐式变换。虽然该算法提供了一种通过炮点剖面偏移成像角度相关反射率的机制，但对于稀疏炮点几何结构，炮点混叠的基本问题可能严重影响CIP道集的质量。
Prestack depth migration of shot profiles by downward continuation is a practical imaging algorithm that is especially cost-effective for sparse-shot wide-azimuth geometries. The interpretation of offset as the displacement between the downward-propagating (shot) wavefield and upward-propagating (receiver) wavefield enables us to extract offset-domain common image-point (CIP) gathers during shot-profile migration. The offset-domain gathers can then be transformed to the angle domain with a radial-trace mapping originally introduced for shot-geophone migration. The computational implications of this procedure include both the additional cost of multioffset imaging and an implicit transformation from shot-geophone to midpoint-offset coordinates. Although this algorithm provides a mechanism for imaging angle-dependent reflectivity via shot-profile migration, for sparse-shot geometries the fundamental problem of shot-aliasing may severely impact the quality of CIP gathers.