扩展的局部Born近似的广义屏算子分析

三维叠前深度偏移广泛地应用于地下复杂地质体成像。当前工作量较大的三维成像问题一般采用基于射线追踪的克希霍夫积分方法,但该方法在处理复杂构造不足。虽然基于有限差分方法的全方程逆时偏移对存在剧烈横向速度变化的非均匀介质也具有非常好的成像精度,但是,把该方法应用于三维叠前深度偏移需要花费较多的机时和巨大的计算机内存容量;这些要求在目前是不现实的。为了寻求一种既方便快捷又准确可靠的叠前深度偏移方法,于是扩展的局部Born近似的广义屏算子在速度场中等程度横向变化情况下,能较准确地描述地震波场的传播过程,对较复杂的地质构造具有较好的成像效果。且该算子具有稳定、高效的优点。不过扩展的局部Born近似的广义屏算子是条件稳定的。但从稳定性和计算效率角度看,该偏移算子可用于目前复杂地质体叠前深度偏移初期处理。

Born approximation of the extended local generalized screen operator analysis

3-d prestack depth migration is widely used in underground complex geological imaging. The current larger workload of 3d isualization problems generally based on ray tracing grams and hoff integration method, but this method in dealing with complex structure inadequate. Although based on all the equation finite difference method to exist severe reverse-time migration of non-uniform horizontal speed change is also very good imaging medium, however, to the precision method is applied to 3-d prestack depth migration takes more machine and huge computer memory capacity, these requirements in the present is not realistic. In order to seek a convenient fast and accurate and reliable prestack depth migration method. So the Born approximation extended local generalized screen operator operator in velocity field moderate horizontal change circumstances, can accurately describe the spread of seismic wave field process, the more complex geological structure has better imaging effect, and this operator has a stable and efficient advantages, but Born approximation of the extended local generalized screen operator is conditions stable. But from the stability and calculation efficiency perspective, this shift operator can be used at present complex geological prestack depth migration initial treatment.