摘要
李录明 ,罗省贤 .波场延拓表层模型校正 .石油地球物理勘探 ,2 0 0 1,36 (5 ) :5 72～ 5 83 为解决复杂表层速度变化对反射波的影响问题 ,在初至波表层模型层析反演的基础上 ,研究了波场延拓表层模型校正的理论方法 ,形成了一套有效的计算方法。其基本原理为 :用分裂法将频率—空间域的纵波位移方程转换为基本波场延拓方程 ,然后进行频散、吸收边界条件校正 ,采用高阶有限差分法求取波场延拓值 ;对于波场延拓横向不变速的情况 ,用相移法求解频率—波数域的单平方根方程进行波场延拓。具体作法为 :1将炮集内的各接收点延拓到高速层顶界 ;2将炮点延拓到高速层顶界 ;3用替换速度分别将接收点和炮点延拓到 CMP位置的基准面 ;4进行速度分析、动校正及叠加 (或直接进行叠前深度偏移 )。理论和实际资料处理结果表明 ,文中方法既可以实现双曲线的变时差校正 。
In order to solve the problem of influence of complicated surface velocity change on reflection wave,on the basis of tomographic inversion of first break surface model,the paper studied theory and method for surface model correction by wave field continuation,and formed a suit of effective calculation method.Its basic principles are:P wave displacement equation in frequency time domain is transformed a basic wave continuation equation by split method,then dispersion and absorption boundary condition is carried out and wave continuation value is obtained by using high order finite difference;in a condition of lateral constant velocity for wave continuation,it carried out by using phase shift method to solve single square root equation in a frequency wavenumber domain.The concrete practices are:①continuation of receiver point on the gather to top of high velocity bed;②continuation of shot point to top of high velocity bed;③separate continuation of receiver point and shot point to datum of CMP position by replaced velocity;④carrying out velocity analysis,NMO correction and stack(or carrying out prestack depth migration directly). Theory and real data processing results showed that the method in the paper both can realize hyperbolic correction for variated time difference and make wavefield after correction satisfy wave character in that position.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2001年第5期572-583,共12页
Oil Geophysical Prospecting
关键词
波场延拓
表层速度模型
层析反演
静校正
地震勘探
wave field continuation,surface velocity model,tomoraphyc inversion,static correction
