三维平面波叠前时间偏移实用化研究

三维平面波叠前时间偏移技术实用性不强,浅层成像信噪比较低,在计算过程中内存开支大,并行节点有效利用率低,且不具有断点保护功能,无法适用于大规模叠前偏移成像处理。为了提高三维平面波叠前时间偏移的实用化水平,从平面波叠前时间偏移原理和实现方案出发,针对存在的问题,提出了相应的解决方案,包括通过倾角滤波方法压制浅层的偏移成像噪声,提高浅层成像信噪比;采用分层成像方案,减小计算过程中的内存开支,提高并行节点的有效利用率;开发断点保护功能,考虑了长时间偏移计算中的断点风险。在应用于某工区实例资料处理后表明,经优化后的平面波叠前时间偏移技术较原平面波偏移具有更好的成像精度,并且具备了大规模数据处理能力。

RESEARCH ON PRACTICALITY OF 3D PLANE-WAVE PRE-STACK TIME MIGRATION

The practicality of 3D plane-wave pre-stack time migration is poor due to several disadvantages,such as low S/N ratio on shallow part of imaging profile,huge memory requirement during calculation,inefficient use of parallel computing nodes,and lacking means for breakpoint protection,etc.,all of which make this technology unsuitable to large-scale seismic data.In order to obtain more practical 3D plane-wave pre-stack time migration,starting from its theory and implementation we propose some appropriate solutions against those previous issues,including suppressing the shallow image noise with dip filters,using a layer-by-layer imaging method to reduce the memory costs and increasing the effective utilization of parallel nodes and developing a breakpoint protection tool for preventing the risk of breakpoint in the long time process.Application to a seismic data shows that the optimized 3D plane-wave pre-stack time migration with a large-scale data processing capability has better imaging precision than the original technology.