起伏地表条件下的相位编码叠前深度偏移

Phase encoding in prestack migration based on irregular surface

波动方程法叠前深度偏移成像精度高,但由于效率低而难以在实际生产中推广应用。以往的许多研究工作都是围绕提高单炮的偏移效率展开,相位编码则是从减少偏移炮数的角度入手来提高偏移效率。相位编码技术隐含着水平地表的假设,因此在起伏地表情况下,就不能按照常规的方式进行编码。通过波动方程的基准面重建,消除了起伏面的影响,在新基准面上按常规的方式进行相位编码,然后对编码后的炮记录进行延拓成像。起伏地表条件下的相位编码技术在一定程度上解决了起伏地表的静校正问题,提高了运算效率。试算表明,该技术成像效果良好,具有较好的应用前景。

Though wave equation prestack migration produces higher quality images,it has not been widely used in practice due to its low efficiency.Many attempts addressing this problem focused on increasing the speed of migration for each individual shot,whereas phase encoding method tries to reduce the number of shots in migration.Phase encoding method implies horizontal surface hypothesis.We firstly reconstructed the datum through wave equation extrapolation,and then implemented phase encoding in migration at the new datum.The feasibility of the proposed method was tested on theoretical models.