高精度屏算子地震偏移成像方法研究

Seismic migration imaging method by using high-precision screen operators.

(1.中国石油化工股份有限公司石油物探技术研究院,江苏南京210014;2.中国石油天然气股份有限公司勘探开发研究院,北京100083;3.中国石油化工股份有限公司江苏油田分公司物探技术研究院,江苏南京210046)

Geophysical Research Institute,SINOPEC,Nanjing 210014,China

从波场延拓的非稳态相移公式出发,基于反问题求解中常用的摄动理论,利用单平方根算子的渐进展开,推导出了波动方程广义屏叠前深度偏移算子方程的高阶形式;针对散射波场计算项对于横向变速介质的不稳定性问题,通过数学近似提出了有效提高稳定性的策略并应用到波场递归外推过程中,从而得到一种稳定的高精度屏算子地震偏移成像方法。数值试验和实际资料处理表明,该方法具有更高的精度,对宽角度信息成像更好，是对传统广义屏算子的有效补充和发展。

Starting from unstable phase-shift formula of wavefield continuation and based on the perturbation theory which is usually used in the solving of inverse question,we derived a high-order form of wave equation generalized screen pre-stack depth migration operator equation by utilizing gradual spreading of single square root operators.Aiming at the instability for the calculation items of scattered wavefield in lateral variable-velocity media,we proposed an effective way to improve the stability by math approximation,and applied it to the wavefield recursion extrapolation.Then a stable seismic migration imaging method of high precision screen operators was obtained.The numerical testing and actual data processing results show that the method has higher precision,which is better for the imaging of wide-angle information,and is the effective supplement and development of traditional generalized screen operators.