平面波射线追踪与面炮波场滞后时间成像

Plane wave ray tracing and areal shot wavelength delay time imaging

面炮(Arealshot)偏移技术是对实际炮集数据按照不同方向传播的平面波进行时间延迟并形成组合炮记录,然后分别作组合震源下行波的向下波场外推和组合记录上行波的向下波场延拓,在相遇深度得到该方向平面波成像的技术。本文基于面炮深度偏移技术,充分利用射线追踪计算量小和波动方程波场延拓具有良好振幅的特性,提出了用平面波射线追踪计算平面波组合震源下行波前走时和面炮波场滞后时间成像的深度偏移方法,着重讨论了有限差分程函方程(Eikonalequation)计算平面波传播时间和组合记录上行波场的滞后时间成像。

Areal shot migration is a plane wave extrapolation technology by which the downgoing wavefield of combined sources and the upgoing wavefield of combined records are downward continued and imaged at meeting depth, these combined sources and combined records are synthesized from all individual shots according to time delays of plane wave with different propagating direction. Based on areal shot migration, a depth migration method with plane wave ray tracing to compute downgoing wavefront of synthesized source and delayed time imaging of downward continued wavefield is proposed, the approach with advantages of cost-effictive of ray tracing and good imaging quality of wave equation is presented, And the discussions on plane wave ray tracing by finite differencing Eikonal equation and delayed time imaging ofupgoing wave field are emphasized here.