【摘要】 基于双程波动方程的逆时偏移被认为是目前最好的偏移成像技术,更适合于复杂构造成像.然而,大计算量和大存储量使得逆时偏移的计算成本很高而无法用于大数据量的地震成像.本文分析了目前常用的存储策略,并分别在空间和时间上对存储策略进行了研究:空间上,根据有限差分格式,在边界存储策略的基础上通过修改波场逆向传播的边界条件,提出了有效边界存储策略.该策略可在不增加任何计算量的情况下大幅降低逆时偏移对存储量的需求;在时间上,使用checkpointing技术对有效边界存储策略进行了改进,使叠前逆时偏移在增加少量计算量的情况下进一步降低存储量需求.Marmousi模型测试结果表明了有效边界存储策略的有效性和优越性.更多还原

【Abstract】 Reverse time migration(RTM),base on two-way wave equation,is regarded as the best migration method to image complex structures.Thus,because of large computation and memory,RTM cannot be used for large seismic data.This paper analyzes the commonly used storage strategies,and improves based on space and time: from the aspect of space,according to difference scheme,by modifying the boundary conditions of backward propagating,proposed efficient boundaries storage strategy based on boundary storage strategy,which can substantially reduce the storage needs of RTM without additional computation;from the aspect of time,improve the efficient boundaries storage strategy by using the checkpointing approach,by which the storage needs can be further reduced with only a few additional computation.Finally,a model test of 2D RTM is done to show the effectiveness and advantages of this new strategy.更多还原