三维叠前偏移新技术

NEW TECHNIC FOR 3D PRESTACK MIGRATION

首次采用空间（ｘ，ｙ）坐标旋转的方法推导出了适应于任何炮检方向并与炮检方向相关的三维波动方程，理论上定量地说明了炮检方向及炮检距与偏移响应的关系，进而证明３Ｄ－ＤＭＯ（叠前部分偏移）只需在炮检方向上进行二维ＤＭＯ即可得以实现。理论模型试算结果表明，该方法正确描述了波的实际传播过程，实现了三维叠前全偏移及３Ｄ－ＤＭＯ处理。

Response of 3D prestack migration is varying with the offset direction, but no such a variance exists for 2D prestack migration.The relationship between varying offset direction and response of prestack migration has not been theoretically known and effectively resolved. This paper for the first time applies(x, y) spatial coordinates rotation to derive offset adaptive and dependent 3D wave equation and theoretically quantifies the relationship between offset direction and migration response.Further more,we demonstrate that 3D-DMO effect iS only relared to offset direction,in other words, 3D-DMO can be implemented by 2D-DMO in offset direction only.The computation result of simulated data shows that the procedure correctly describes the actual propagation of waves and realzies 3D prestack migration and 3D-DMO processing.