叠前深度偏移技术在盐系地层中的应用

Application of pre-stack depth migration technique in salt bed

在地下构造较复杂时,叠后时间剖面叠加处理的效果不太理想。叠前深度偏移直接对叠前数据进行偏移处理,避免了时间叠加处理过程,能有效控制横向速度变化,利用射线追踪原理进行偏移,整个处理过程中利用层析成像等技术不断优化深度-速度模型,可得到比叠后时间偏移更好的效果。江汉盆地潜江凹陷部分盐构造区的叠前深度偏移处理取得了较好的效果,表明叠前深度偏移是复杂构造及速度横向变化大地区地震资料处理的理想技术。

The post-stack time section processing is not satisfactory when the subsurface structure is complex. The pre-stack depth migration avoids the process of superposition in time by directly processing the pre-stack data, which can efficiently control the lateral variation of velocity field. Based on the theory of ray tracing, the tomography image technology is used continuously to optimize the velocity-depth model during the whole processing, and the result indicates that the pre-stack depth migration is better than the post-stack time migration. The pre-stack depth migration has been successfully used in some parts of salt bed in Qianjiang Sag for the data processing and good effect is achieved, showing that the pre-stack depth migration technique is an ideal technique in complex areas and lateral variation of velocity zones.