波场延拓短算子构造方法

在频率-空间域显式叠前深度偏移中，波场深度延拓是通过显 式差分短算子与波场的空间褶积完成的. 基于对显式差分短算子的设计方法的研究，提出了 一种基于相移算子约束的离散光滑插值的构造一维显式短算子的方法. 通过离散光滑插值法 ，在频率-波数域中，以传播区内的相移算子为约束，在传播区外的算子两端处以零点为约 束，进行离散光滑插值，使得所得算子具有二阶光滑可导性，则其对应的频率-空间域中的 算子就可以取得很短. 该方法设计简单，精度高，能够满足波场深度延拓的需要.

METHOD OF CREATING SHORT OPERATOR OF WAVEFIELD EXTRAPOLATIN G

In explicit depth extrapolation method of frequency-space fields, wavefield depth extrapolation is completed with convolution of short explicit difference operators and the wavefield. Based on the study of the method of creating short explicit difference operators, a method for creating short explicit operators is presented, which is based on discrete smooth interpolation with control of phase-shift operator. In the wavefield-spread area, we uses the phase-shift operator as constraint in frequency-wavenumber field, while beyond the wavefield-spread data, we uses zero point at the ends of phase-shift operator as constraint to take discrete smooth interpolation so that the resulted operator satisfies two-order smooth and the length of this operator can be selected shorter in frequency-space field. This method has simple creating process and high precision, and can be used in wavefields depth extrapolation.