非稳态相移法叠前深度偏移

介绍一种能够适应介质速度横向变化的非稳态相移算子及其叠前深度偏移方法．为了克服常规相移偏移算法中要求速度横向不变的缺点，出现了基于非稳态滤波器理论的非稳态相移算子，即PSPI算子、NSPS算子和SNPS算子，其中SNPS算子是将前二者结合起来的一种对称的非稳态相移算子，它比前二者具有更高的精度和稳定性．为了提高运算速度，基于非稳态相移算子的叠前深度偏移算法采取了分片均匀近似的策略，Marmousi模型的叠前深度偏移结果证明了该算法的可行性和有效性。

Prestack depth migration by nonstationary phase shift method

The paper introduces a prestack depth migration by nonstationary phase shift method suitable for laterally variable velocity. Conventional phase shift operator requires that the velocity be laterally constant, while nonstaionary phase shift operators such as PSPI, NSPS SNPS overcome the shortcoming. The symmetric SNPS operator, a combination of NSPS and PSPI, has better accuracy and stability than NSPS or PSPI. For the sake of computation cost, prestack depth migration by nonstationary phase shift is implemented using a piecewise constant approximation, the migrated Marmousi result shows that the nonstationary phase shift migration for heterogenous media is feasible.